Dissertations / Theses: 'Fruit juices'

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Gomez, Stéphanie Madeleine. "Fruit juices market in France." CSUSB ScholarWorks, 2001. https://scholarworks.lib.csusb.edu/etd-project/2004.

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The purpose of this project is to offer a market study of the fruit juices market in France. The aim is to propose not only a comprehensive analysis of the fruit juices market in France, but also a set of recommendations that could be used by managers of fruit juices companies in sustaining a mature market.

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Burch, Rachel S. B. "Analysis of phenolic compounds in tropical fruit juices." Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265174.

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Kamau, Caroline M. "Fruit Juices: Ellagic Acid Concentration and Sensory Appeal." Bowling Green State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1182707084.

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Garcia-Wass, Febe. "Orange juice authenticity using pyrolysis mass spectrometry." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312084.

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Bodley, Mark David. "Application of bacteriocins in the preservation of fruit juice." Thesis, Nelson Mandela Metropolitan University, 2015. http://hdl.handle.net/10948/d1020188.

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Bacteriocins (BCNs) are ribosomally synthesized polypeptides or proteins with antimicrobial activity, produced by different groups of bacteria. Many lactic acid bacteria (LAB) produce BCNs with broad spectra of inhibition. The antimicrobial activity of BCNs against spoilage organisms (SPOs) has raised considerable interest in their application in juice preservation. The objectives of the study were to: (i) isolate, identify and screen BCN producing bacteria for antimicrobial activity against spoilage bacteria and fungi, (ii) optimize production of BCN from selected producers and (iii) investigate the industrial application of the BCN as a preservative in fruit juice. Eleven LAB strains of BCN producers were screened for antimicrobial activity. BCNs from Lactobacillus plantarum and Pediococcus pentosaceus 34 were the most effective against juice spoilage bacteria and fungi. The effect of medium components on bacteriocin production in L. plantarum and P. pentosaceus 34 was also determined. Clementine:Valencia (1:1) juice was used for the first time as the growth medium for L. plantarum and P. pentosaceus 34. The BCN from L. plantarum showed the highest activity and was, therefore, chosen for juice fermentation studies. The identification of L. plantarum was confirmed by biochemical tests, polymerase chain reaction (PCR) and sequencing of the recA gene. The highest BCN activity was observed for L. plantarum grown in De Man-Rogosa-Sharpe (MRS) and a combination of all supplements (i.e. peptone, MnSO4.H2O, Tween 80, glucose and whey), followed by MRS and Tween 80, peptone, MnSO4.H2O and MRS alone. MRS was a better medium for BCN production than juice [Clementine:Valencia (1:1)]. Size exclusion chromatography (SEC) was used to isolate the active L. plantarum BCN fraction which corresponded to an approximate molecular weight of 3.2 kDa and was proteinaceous in nature. Plantaricin structural genes (plnEF, plnJ, plnK, plnN) were detected in the L. plantarum strain by PCR and sequenced, and were chromosomally encoded as no plasmids could be detected. This implies that the BCN from L. plantarum is most likely a type of class IIa plantaricin which is responsible for the broad inhibitory activity observed. For the industrial application studies, L. plantarum BCN-containing cell free supernatant (BCNsup) added to “Ready to Drink” (RTD) Clementine:Valencia (1:1) juice at concentrations of 3 600 - 500 000 ppm decreased growth of SPOs, Lactobacillus acidophilus and Streptococcus thermophilus. At 250 000 ppm, the L. plantarum BCNsup achieved 5.3 and 6.8 log reductions of the L. acidophilus, after 24 and 48 h, respectively, which is larger than the USFDA (2001) requirement of a 5 log reduction in SPO activity, for preservation of fruit juices. However, there was a decrease in the activity when the BCNsup was applied to industrial (Valor) RTD juice (mango-orange) at decreasing concentrations of 100 000, 50 000 and 25 000 ppm. Organoleptic tests showed that the BCN did not alter flavor or taste of the juice and did not cause toxicity or allergic reactions. A food safety risk assessment was conducted in order to determine the Critical Control Point(s) [CCP(s)] at which the BCN could be applied to control identified microbiological hazards, and a Hazard Analysis and Critical Control Point (HACCP) plan was developed. This is the first report on the optimisation of L. plantarum BCN production in juice [Clementine:Valencia (1:1)], followed by inoculation into RTD juice (mango-orange), including a HACCP plan for the application of the BCN as a preservative in juice.

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Duvenage, Wineen. "Detection and isolation of thermophilic acidophilic bacteria from fuit juices." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/3016.

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Thesis (Msc Food Sc (Food Science))--University of Stellenbosch, 2006. Fruit juices were until recently considered to only be susceptible to spoilage by yeasts, mycelial fungi and lactic acid bacteria. Spoilage by these organisms was prevented by the acidic pH of fruit juices and the heat-treatment applied during the hot-fill-hold process. Despite these control measures, an increasing number of spoilage cases of fruit juices, fruit juice products and acidic vegetables due to contamination by thermophilic acidophilic bacteria (TAB) have been reported. The genus Alicyclobacillus, containing TAB were first classified as Bacillus, but were reclassified in 1992. Species of Alicyclobacillus are Gram-positive, rod-shaped, endospore-forming bacteria. The unique characteristic of these organisms is the presence of ω-alicyclic fatty acids, such as ω-cyclohexane and ω-cycloheptane, as the major components of the cellular membrane. This organism has been shown to survive pasteurisation conditions of 95°C for 2 min and grows within a pH range of 2.5 to 6.0 and temperatures between 25° and 60°C. The genus currently consists of 11 species, with A. acidoterrestris, A. acidocaldarius and A. pomorum being the only species associated with the spoilage of fruit juices and fruit juice products. The aim of this study was to evaluate culture-dependent and culture-independent approaches for the detection and isolation of Alicyclobacillus spp. from pasteurised South African fruit juices and concentrates. The culture-dependent approach was evaluated by comparing five different growth media, for growth and recovery of A. acidoterrestris, A. acidocaldarius and A. pomorum at different incubation temperatures, from sterile saline solution (SSS) (0.85% (m/v) NaCl), diluted and undiluted fruit juice concentrates. The five media evaluated included potato dextrose agar (PDA), orange serum agar (OSA), K-agar, yeast extract (YSG)-agar and Bacillus acidocaldarius medium (BAM). The culture-independent approach was used to identify the micro-organisms present in fruit juices and concentrates from different South African manufacturers before and after pasteurisation, using polymerase chain reaction (PCR)-based denaturing gradient gel electrophoresis (DGGE) and DNA sequencing. Spread plates of PDA at pH 3.7 and incubation temperature of 50°C for 3 days was found to be the best isolation media for species of Alicyclobacillus from fruit juice and fruit juice concentrate. With the inclusion of a heat shock treatment at 80°C for 10 min the growth media of preference for spores of Alicyclobacillus from fruit juice concentrates was OSA at pH 5.5 and an incubation temperature of 50°C for 3 days. The culture-dependent approach could detect cells or endospores at a minimum concentration of 104 cfu.ml-1 in SSS and diluted fruit juices. PCR-based DGGE analysis was more sensitive and detected cells of Alicyclobacillus spp. from fruit juices and concentrates at a minimum concentration of 103 cfu.ml-1. Alicyclobacillus acidoterrestris was found to be present in South African apple juice, pear juice, white grape juice and aloe vera juice. White grape juice was also found to contain A. pomorum. Other organisms present in the orange, apple, mango and pear juices were two uncultured bacteria that were identified as members of the genus Bacillus, and one uncultured bacterium closely related to Alcaligenus faecalis. This study confirmed the presence of TAB in pasteurised South African fruit juices and concentrates and emphasises the need for the rapid and accurate detection of TAB in food products.

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Khumalo, Wilson Mdala. "The value of measuring brand equity: the Ceres Fruit Juices case." Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/995.

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Measuring brand equity is an important brand management function but, the appropriateness of brand equity measurement methods remain a concern. This study applied levels three of brand equity measurement approach to have an understanding of consumers’ brand perception. It is hoped that this understanding could give brand managers the necessary tool to develop and deploy effective and efficient brand management strategies and tactics. At Ceres Fruit Juices (CFJ), brand equity is used to improve competitive marketing actions, gain larger margins, intermediary co-operation and management support for brand extension. This study measures CFJ Brand equity to understand consumers’ perception so that this understanding can be used to develop responsive brand management strategies and tactics. Brand equity measurement methods and model found in the literature shows that measurement success depends on the suitability of the method used. However, customers’ perception is at the centre of brand equity measurement approach – level three used in this study. With merger and acquisition taking place at Ceres Fruit Juices, brand equity measurement emerged as an important brand management function to leverage real brand value. This would inevitably lead to an improvement in customer service through adequate understanding of customers brand perception. Understanding gives brand managers the necessary tool to deploy responsive and efficient brand management strategies and tactics to lessen the severity of the negative impact merger and acquisition may have on brand equity. Thus, this study found measurement model and method to be an essential element of brand equity measurement.

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Tajchakavit, Sasithorn. "Microwave heating of fruit juices : kinetics of enzyme inactivationmicrobial destruction and evaluation of enhanced thermal effects." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35414.

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Conventional thermal kinetics of enzyme inactivation and microbial destruction in fruit juices were studied in the pasteurization temperature range (50 to 90°C). Pectin methylesterase (PME), as the most heat resistant enzyme, in orange juice and Saccharomyces cerevisiae and Lactobacillus plantarum, as the most common spoilage yeast and bacteria, respectively, in apple juice used as indicators were subjected to heat treatment in a well-agitated water bath. Based on gathered time-temperature profiles, effective portions of the come-up (CUT) and come-down (CDT) times (lags) were determined for inclusion in kinetic data handling. The inactivation/destruction kinetics followed typical first-order rate of reactions. A continuous-flow microwave heating system was set up and evaluated for obtaining kinetic parameters under microwave heating conditions. The outlet temperature was characterized as a function of fluid flow rate, heating volume and initial temperature. Kinetics of enzyme inactivation and microbial destruction at various temperatures under continuous-flow microwave heating conditions were then evaluated using the technique established above. The rates of inactivation/destruction varied depending on temperature. Taking into consideration the effectiveness of the CUT and contributory thermal inactivation during the CDT, the D-values were found to vary from 38.5 s at 55°C to 1.32 s at 70°C (pH 3.7) for PME, 4.75 s at 52.5°C to 0.378 s at 60°C (pH 3.4) for S. cerevisiae (ATCC 16664) and 14.1 s at 57.5°C to 0.327 s at 65°C (pH 3.4) for L. plantarum (ATCC 14917). Some non-thermal microwave effects were hypothesized to exist and responsible for such differences between the two heating modes. Enzyme inactivation and microbial destruction were then studied further to evaluate the non-thermal effects. A continuous-flow microwave heating system was developed operating at full power while maintaining sample temperatures below 40°C by circulating a microwave-transparent liquid (kerosene) for immediate removal of heat produced in the juice during microwave exposure. In order to explain and better characterize the faster rate of inactivation/destruction associated with microwave heating conditions observed in kinetic studies, additional tests were carried out using the second set-up described above, but without the cooling heat exchanger. The temperature of samples of different sizes were allowed to progressively increase under carefully controlled conditions. Inactivation of PME in orange juice (pH 3.7) and destruction of S. cerevisiae in apple juice (pH 3.4) were again used as parameters. The results once again clearly demonstrated superior inactivation/destruction effects under microwave heating which increased with temperature and decreased with sample size. (Abstract shortened by UMI.)

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Aguilar, Lara Karla. "Effect of ultraviolet/visible radiation processing on the quality of fruit juices." Doctoral thesis, Universitat de Lleida, 2017. http://hdl.handle.net/10803/405804.

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Aquest treball va estudiar la irradiació ultraviolada-visible (UV-Vis) com una alternativa per a la pasteurització de sucs. Els resultats van mostrar que la irradiació ultraviolada no produeix hidroximetilfurfural i es capaç de degradar-lo. Es va proposar un mecanisme de foto-degradació i es van usar diferents models cinètics per descriure la reacció. La foto-degradació de la vitamina C va ser insignificant usant una làmpada d’emissió múltiple. A més, el processament d’UV-Vis va ser efectiu inactivant els enzims polifenoloxidasa i peroxidasa; a major temperatura major inactivació. Mentrestant, la majoria dels paràmetres fisicoquímics van ser pràcticament inalterats i la quantitat inicial de pigments es va reduir. Per tant, el processament d’UV-Vis combinat amb lleu escalfament és una alternativa viable per a la pasteurització de sucs. Este trabajo estudió la irradiación ultravioleta-visible (UV-Vis) como una alternativa para la pasteurización de zumos. Los resultados demostraron que la irradiación ultravioleta no produce hidroximetilfurfural y es capaz de degradarlo. Se propuso un mecanismo de foto-degradación y se usaron diferentes modelos cinéticos para describir la reacción. Por el contrario, la foto-degradación de la vitamina C fue insignificante usando una lámpara de emisión múltiple. Además, el procesamiento UV-Vis fue efectivo inactivando las enzimas polifenoloxidasa y peroxidasa en zumos; a mayor temperatura, mayor inactivación. Mientras tanto, la mayoría de los parámetros fisicoquímicos fueron prácticamente inalterados y la cantidad inicial de pigmentos fue reducida. Por lo tanto, el procesamiento UV-Vis combinado con un calentamiento suave representa una alternativa viable para la pasteurización de zumos. This work studied the ultraviolet-visible (UV-Vis) irradiation as an alternative for fruit juice pasteurisation. The results showed that ultraviolet irradiation does not produce hydroxymethylfurfural and is capable of degrade it. A mechanism of photo-degradation was proposed and different kinetic models were used to describe the reaction. On the contrary, the photo-degradation of vitamin C was insignificant using a multi-wavelength emitting lamp. Moreover, the UV-Vis processing was effective inactivating the enzymes polyphenoloxidase and peroxidase in fruit juices. The higher the temperature the higher the inactivation. Meanwhile, most physicochemical parameters were practically unaltered and the initial quantity of pigments was reduced. Therefore, the UV-Vis processing combined with a mild-heating represents a viable alternative for fruit juice pasteurisation.

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Silva, Djany Souza. "Evaluation of mathematical models to prediction the dynamic viscosity of fruit juices." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14440.

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CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior O consumo de sucos de frutas tem crescido, devido a comodidade e praticidade gerada pelos produtos prontos. Segundo a AssociaÃÃo Brasileira das IndÃstrias de Refrigerantes, em 2012, a produÃÃo anual foi de 987 milhÃes de litros de sucos de frutas no Brasil. No entanto, para alcanÃar maior eficiÃncia e rendimento, torna-se necessÃrio o conhecimento do comportamento reolÃgico das matÃrias-primas. A viscosidade Ã uma das propriedades reolÃgicas usada em diversas aplicaÃÃes, tais como: parÃmetro para o cÃlculo de coeficientes de transferÃncia de calor e massa; dimensionamento de equipamentos; avaliaÃÃo de custos; projetos de processos; controle de qualidade do produto; alÃm de possibilitar a compreensÃo da estrutura quÃmica das matÃrias-primas. Durante o processamento industrial dos sucos de frutas, a matÃria-prima Ã submetida Ã variaÃÃes de temperaturas e concentraÃÃes de sÃlidos que alteram sua viscosidade. Por esse motivo, o conhecimento dos efeitos combinados desses dois parÃmetros na viscosidade Ã essencial para a indÃstria de sucos. Nesse trabalho, dados experimentais da literatura para onze sucos clarificados de frutas (manga, cereja, maÃÃ, pÃssego, groselha, romÃ, pÃra, limÃo, tangerina, limÃo-galego e uva) em concentraÃÃes e temperaturas de 15,0 a 74,0 ÂBrix, e 278,15 a 393,15 K, respectivamente, foram modelados utilizando correlaÃÃes empÃricas e semi-empÃricas oriundas da literatura. ParÃmetros globais e especÃficos, respectivamente, em funÃÃo da temperatura e concentraÃÃo de sÃlidos solÃveis totais (SST), foram mantidos nos modelos. Quatro equaÃÃes foram avaliadas no cÃlculo da energia de ativaÃÃo (equaÃÃo da reta, exponencial, polinomial de 2Â e 3Â ordem) nos modelos. E trÃs estratÃgias de modelagem foram realizadas: ajuste para todas as concentraÃÃes de SST e temperaturas; em diferentes faixas de concentraÃÃes de SST; e, diferentes faixas de temperaturas. A estratÃgia de otimizaÃÃo por faixas de concentraÃÃes de SST mostrou-se a mais adequada. Duas relaÃÃes matemÃticas exponenciais, baseadas na correlaÃÃo de Arrhenius, obtiveram bons resultados na prediÃÃo da viscosidade dinÃmica de sucos de frutas clarificados entre as concentraÃÃes de 17,0 a 50,1 ÂBrix para todas as temperaturas de estudo. Enquanto que o uso da equaÃÃo de Vogel obteve bons resultados para concentraÃÃes de 51,0 a 66,0 ÂBrix na prediÃÃo da viscosidade dinÃmica dos sucos de frutas. Os modelos foram validados com dados experimentais para suco clarificado de laranja em baixas (30,7 a 50,5 ÂBrix) e altas concentraÃÃes (54,1 a 63,5 ÂBrix) de SST, com excelente prediÃÃo da viscosidade dinÃmica. The comsumption of fruit juices has grown due to co nvenience and practicality generated by the finished products. According to the AssociaÃÃo Brasileira das IndÃstrias de Refrigerantes, in 2012 the annual production was 987 million liter s of fruit juices in Brazil. However, to achieve greater efficiency and performance, it is n ecessary to know the rheological behavior of the raw materials. Among rheological properties, viscosity is widely used in industrial and academic applications such as: a parameter for the calculation of heat and mass transfer coefficients; equipment design; cost assessment; de sign processes; quality control of the product; and enable an understanding of the chemica l structure of raw materials. During industrial processing of fruit juices, the raw mate rials are submitted to temperatures and concentrations of solids variations that altering i ts viscosity. Therefore, the knowledge of the combined effect of temperature and concentration of solids on viscosity are essential for the juice processing. In this work, literature data fro m eleven clarified juices of fruit (mango, cherry, apple, peach, blackcurrant, pomegranate, pe ar, lemon, tangerine, lime and grape) at concentrations and temperatures from 15.0 to 74.0 Â Brix and from 278.15 to 393.15 K, respectively, were modeled using empirical and semi -empirical correlations derived from the literature. Global and specific parameters for all studied models been obtained in function of temperature and total soluble solids (TSS) concentr ation. Four equations were evaluated to calculate the activation energy in each model (line ar equation, exponential, polynomial of 2nd and 3rd order) using activation energy as specific parameter, and three different modeling strategies were conducted: for all TSS concentratio ns and temperatures; two ranges concentrations of TSS; and, two ranges of temperatu res. The optimization strategy for the concentrations TSS range proved the most suitable. Two exponential mathematical relations based on correlation of Arrhenius have been success ful in predicting the dynamic viscosity of clarified fruit juices at concentrations from 17.0 to 50.1 ÂBrix for all temperatures studied. While Vogel's equation obtained good results for co ncentrations of 51.0 to 66.0 ÂBrix in predicting the dynamic viscosity of fruit juices. T he models were validated using experimental data to clarified orange juices at low (30.7 to 50.5 ÂBrix) and high concentrations (54.1 to 63.5 ÂBrix) of TSS, with ex cellent prediction of dynamic viscosity

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Kaneiwa, Kubo Mirian Tiaki. "Thermal process of fruit juices using microwaves : multiphysics modeling and enzyme inactivation." Thesis, Nantes, Ecole nationale vétérinaire, 2018. http://www.theses.fr/2018ONIR116F/document.

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Ce travail vise à étudier l'intérêt duchauffage micro-ondes pour l'inactivation desenzymes dans les jus de fruit, à travers desapproches numériques et aussi expérimentales.En premier lieu, une étude sur les propriétésdiélectriques des jus de fruits modèles est menée,démontrant leur forte sensibilité à la température,à la fréquence et à la composition du produit. Dansune seconde partie, l'inactivation de la peroxydaseest étudiée par chauffage conventionnel et lesdonnées sont ajustées par un modèle cinétique dupremier ordre. Dans la troisième et principalepartie de ce travail, un modèle tridimensionnel,résolu par éléments finis, est proposé pour simulerle chauffage par micro-ondes du jus, en couplantélectromagnétisme, transfert de chaleur etécoulement, avec la cinétique d'inactivation de laperoxydase précédemment déterminée.Cette simulation permet de prédire la distributionspatiale de la température, le profil d’écoulementet l'inactivation de la peroxydase. L’accord entre lemodèle et les expériences est très satisfaisant, cequi confirme la pertinence de l’approche. Dans ladernière partie, les réactivations de la peroxydaseaprès chauffage conventionnel et micro-ondessont évaluées et comparées. Enfin, l’éventuelleexistence d’effets non thermiques des microondesest discutée via des expériencesadditionnelles. En conclusion, ces travauxmontrent tout l’intérêt de la simulation numériquecomme outil de compréhension du processusmultiphysique du chauffage par micro-ondes pourl’inactivation des enzymes, ce qui peut êtreparticulièrement intéressant pour la conception etl’optimisation de traitements micro-ondes This work aims at studying the use ofmicrowave heating for enzyme inactivation in fruitjuices by means of numerical and experimentalapproaches. In the first part, a study on thedielectric properties of model fruit juices isconducted, evidencing their high dependence onthe temperature, frequency and composition of theproduct. Then in the second part, the inactivation ofperoxidase is studied using conventional heatingand the data are fitted by a first order kinetic model.In the third and main part of this work, a threedimensionalfinite element model is developed tosimulate the microwave heating of juices, couplingelectromagnetics, heat transfer and fluid flow aswell as the peroxidase inactivation kineticspreviously determined.As a result, spatial temperature distribution, flowpattern and peroxidase inactivation are obtained.The model is experimentally validated and goodagreement is observed, confirming the relevanceof the approach. Finally, in the last part, thepotential peroxidase reactivations afterconventional and microwave heating areassessed and compared. Also, the possibleexistence of non-thermal effects of microwaves isdiscussed thanks to additional experimentations.In conclusion, this work shows the large interest ofcomputer simulation as a tool for understandingthe multiphysics process of microwave heating forenzyme inactivation, which can be particularlyinteresting for further design of optimizedmicrowave processing

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Kaneiwa, Kubo Mirian Tiaki. "Thermal process of fruit juices using microwaves : multiphysics modeling and enzyme inactivation." Electronic Thesis or Diss., Nantes, Ecole nationale vétérinaire, 2018. http://www.theses.fr/2018ONIR116F.

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Ce travail vise à étudier l'intérêt duchauffage micro-ondes pour l'inactivation desenzymes dans les jus de fruit, à travers desapproches numériques et aussi expérimentales.En premier lieu, une étude sur les propriétésdiélectriques des jus de fruits modèles est menée,démontrant leur forte sensibilité à la température,à la fréquence et à la composition du produit. Dansune seconde partie, l'inactivation de la peroxydaseest étudiée par chauffage conventionnel et lesdonnées sont ajustées par un modèle cinétique dupremier ordre. Dans la troisième et principalepartie de ce travail, un modèle tridimensionnel,résolu par éléments finis, est proposé pour simulerle chauffage par micro-ondes du jus, en couplantélectromagnétisme, transfert de chaleur etécoulement, avec la cinétique d'inactivation de laperoxydase précédemment déterminée.Cette simulation permet de prédire la distributionspatiale de la température, le profil d’écoulementet l'inactivation de la peroxydase. L’accord entre lemodèle et les expériences est très satisfaisant, cequi confirme la pertinence de l’approche. Dans ladernière partie, les réactivations de la peroxydaseaprès chauffage conventionnel et micro-ondessont évaluées et comparées. Enfin, l’éventuelleexistence d’effets non thermiques des microondesest discutée via des expériencesadditionnelles. En conclusion, ces travauxmontrent tout l’intérêt de la simulation numériquecomme outil de compréhension du processusmultiphysique du chauffage par micro-ondes pourl’inactivation des enzymes, ce qui peut êtreparticulièrement intéressant pour la conception etl’optimisation de traitements micro-ondes This work aims at studying the use ofmicrowave heating for enzyme inactivation in fruitjuices by means of numerical and experimentalapproaches. In the first part, a study on thedielectric properties of model fruit juices isconducted, evidencing their high dependence onthe temperature, frequency and composition of theproduct. Then in the second part, the inactivation ofperoxidase is studied using conventional heatingand the data are fitted by a first order kinetic model.In the third and main part of this work, a threedimensionalfinite element model is developed tosimulate the microwave heating of juices, couplingelectromagnetics, heat transfer and fluid flow aswell as the peroxidase inactivation kineticspreviously determined.As a result, spatial temperature distribution, flowpattern and peroxidase inactivation are obtained.The model is experimentally validated and goodagreement is observed, confirming the relevanceof the approach. Finally, in the last part, thepotential peroxidase reactivations afterconventional and microwave heating areassessed and compared. Also, the possibleexistence of non-thermal effects of microwaves isdiscussed thanks to additional experimentations.In conclusion, this work shows the large interest ofcomputer simulation as a tool for understandingthe multiphysics process of microwave heating forenzyme inactivation, which can be particularlyinteresting for further design of optimizedmicrowave processing

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Hussain, Sadul Fath. "Application of pyrolysis-mass spectrometry as a rapid analytical method in food science." Thesis, University of Reading, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335921.

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Hartman, Angela Danielle. "The Efficacy of Antimicrobials for the Control of Alicyclobacillus acidoterrestris in Fruit and Vegetable Juices." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/33739.

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The efficacy of antimicrobials for control of A. acidoterrestris spoilage in juices was analyzed. Apple and tomato juices were inoculated with 4 log spores/ml. Antimicrobials were added at: 1000, 500 and 250 ppm (sodium benzoate, potassium sorbate, and sodium metabisulfite); 500, 250, and 125 ppm (cinnamic acid, dimethyl dicarbonate, and ascorbic acid); 125, 75 and 25 ppm (lysozyme); and 5, 3, and 1 IU/ml (nisin). In apple juice, A. acidoterrestris population reductions were caused by the following antimicrobials (reduction in log CFU/ml): lysozyme - all levels and nisin - 5 IU/ml (5.1), nisin - 3 IU/ml (4.2), cinnamic acid - 125 ppm (3.1), cinnamic acid - 250 ppm (2.6), potassium sorbate - 250ppm (2.5), nisin - 1 IU/ml (2.4), potassium sorbate - 500 and 1,000 ppm (2.3), dimethyl dicarbonate - 500 ppm (1.9), cinnamic acid - 500 ppm (1.4). In tomato juice, A. acidoterrestris population reductions were caused by the following antimicrobials (reduction log CFU/ml): nisin - all levels and lysozyme - 125 ppm and 75 ppm (4.4), lysozyme - 25 ppm (3.8), potassium sorbate - 500 ppm (2.6), cinnamic acid - 500 ppm (2.5), cinnamic acid - 250 ppm (2.4), cinnamic acid - 125 ppm (2.1), potassium sorbate - 1,000 ppm (1.9), and potassium sorbate - 250 ppm (1.6). Antimicrobial treatments: nisin - Â¡Ã 1 IU/ml, lysozyme - Â¡Ã 25 ppm, cinnamic acid - Â¡Ã 125 ppm, and potassium sorbate - Â¡Ã 250 ppm may be appropriate controls to prevent A. acidoterrestris spoilage in juices or juice containing beverages. Master of Science

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Walker, Michelle. "The prevention of spoilage in fruit juices by alicyclobacillus acidoterrestris and propionibacterium cyclohexanicum." Thesis, University of Northampton, 2006. http://nectar.northampton.ac.uk/2664/.

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During the past two decades several novel spoilage micro-organisms have emerged. Raw materials and products have been contaminated in increasing numbers of spoilage incidents causing widespread problems within the juice and beverage industry. This study investigates two such spoilage micro-organisms, A licyclobacillus acidoterrestris and Propionibacterium cyclohexanicum, both isolated from pasteurised contaminated fruit juice. A variety of media were tested to determine which supported optimal growth of A. acidoterrestris with Orange Serum Agar providing consistently high plate counts. The presence of A. acidoterrestris in raw materials and shelf stable products was monitored and the effects on its growth and survival of temperature, headspace and movement of containers during storage were investigated. The survival of P. cyclohexanicum after pasteurisation was assessed and growth determined at a variety of temperatures. The survival of each bacterium was investigated in different fruit juices, when challenged by the preservatives sodium benzoate and potassium sorbate and the bacteriocin nisin and when grown in the same juice container and co-cultured on the same solid medium. 17% of samples tested were contaminated by A. acidoterrestris; however P. cyclohexanicum was not isolated from any sample. P. cyclohexanicum survived 10 minutes at temperatures of 4°C to 95°C and grew in orange, tomato and pineapple juice while A. acidoterrestris grew in all juices tested. A. acidoterrestris was inhibited by sodium benzoate (500ppm), potassium sorbate (500ppm) and nisin (51U/ml). P. cyclohexanicum, although not inhibited by nisin (1000IU/ml), was susceptible to sodium benzoate (500ppm) and potassium sorbate (l000ppm). I-Ieadspace, movement of containers and storage temperatures affected detection rates of A. acjdoterrestrjs. Co-cultures demonstrated that if found within the same enviromnent, both bacilli can survive and cause spoilage. A. acidoterrestris is a world wide contaminant within the soft drinks industry and, considering the results of these studies P. cyclohexanicum with its heat resistance and tolerance to nisin may also emerge as a major spoilage microorganism

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Piotrowski, Christine Lelia. "Survival of Listeria monocytogenes in Fruit Juices During Refrigerated and Temperature-Abusive Storage." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/9619.

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Survival of Listeria monocytogenes in apple, orange, red grape, and white grape juice was evaluated. A six-strain cocktail of L. monocytogenes was used to inoculate (approx. 7 log cfu/ml) fruit juices, which were stored at 4, 10 and 24°C for up to 61 days. Inoculated red grape juice was stored for up to 5 hours only. Samples were withdrawn at appropriate intervals, neutralized with 1.0 N NaOH, serially diluted in 0.1% peptone water, and surface plated onto Tryptic Soy Agar + 0.6% Yeast Extract (TSAYE) and Modified Oxford Agar (MOX), followed by incubation at 32°C for 48 hours. When L. monocytogenes was no longer detected by direct plating, samples were enriched for L. monocytogenes using Listeria Enrichment Broth (LEB), followed by isolation on MOX. L. monocytogenes remained viable in white grape, apple, and orange juices for up to 12, 24 and 61 days, respectively. Over time, recovery of Listeria on TSAYE versus MOX was not significantly different (P>0.05), indicating that limited acid-injury developed during storage. The results of this study demonstrate the ability of L. monocytogenes to survive in apple, orange, and white grape juices during refrigerated and abusive storage conditions. Therefore, measures to prevent or eliminate L. monocytogenes in the fruit juice-processing environment are necessary to ensure the safety of juice products for public consumption. Master of Science

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Musella, Michele Ann. "Food marketing distribution : a pilot study of Ardmore Farms /." Online version of thesis, 1991. http://hdl.handle.net/1850/11788.

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Campbell, Ian Gavin A. "An overview of emerging trends in pathogen reduction in the processing of fruit juices." Kansas State University, 2014. http://hdl.handle.net/2097/18643.

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Master of Science Department of Animal Sciences and Industry Food Science Elizabeth Boyle Unpasteurized fruit juices have been implicated as the source of foodborne outbreaks due to pathogens such as Salmonella, Escherichia coli O157: H7 and Cryptosporidium parvum. The growth of pathogens can usually be slowed through freezing or largely eliminated through pasteurization. Although pasteurization is often effective in eliminating pathogens, it often yields undesirable flavors that are unlike those of fresh juice. Growing consumer trends towards “healthy” unpasteurized alternatives are fueling the development of alternative processing techniques. Several promising techniques for pathogen reduction in the processing of fruit juices are currently being developed. A new technique that is already being marketed worldwide is hyperbaric processing (HPP) which subjects the fruit juice to a high pressure of up to 1000 MPa. The high-pressure treatment results in up to a 7 log reduction kill in pathogens while preserving the naturally occurring flavor profile, sensory attributes and nutritional benefits. Pulsed electric fields (PEF) and ionizing radiation are also being widely explored as viable techniques to process unpasteurized fruit juices. PEF promises to be a commercially viable energy efficient alternative to pasteurization, adding only $0.03 – $0.05 per liter to final food costs. Although irradiation enjoys support for use in the processing of fruit juice by regulatory agencies, support in public opinion is lacking and hinders its growth as an alternative to pasteurization. Other experimental techniques are also present in the development pipeline. Ultrasonic radiation and high intensity pulsed light radiation are both experimental techniques that are being researched. A particularly exciting alternative is the use of plant-based antimicrobials. Several fruits and spices are known to be natural antimicrobials and are therefore being researched as alternatives to the traditional chemical preservatives.

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Groenewald, Willem Hermanus. "Taxonomy of species of Alicyclobacillus from South African orchards and fruit concentrate manufacturing environments and the prevention of fruit juice contamination." Thesis, Stellenbosch: University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1253.

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Thesis (PhD (Food Science))--University of Stellenbosch, 2009. ENGLISH ABSTRACT: Species of Alicyclobacillus are acid-tolerant and heat-resistant bacteria that cause spoilage of heat-treated fruit juices stored at room temperature. During the past decade, Alicyclobacillus spp. have become a major cause of spoilage in pasteurised fruit juices leading to significant economic losses world-wide. Spoilage has been reported in apple, pear, orange, peach, mango and white grape juice, as well as in fruit juice blends, fruit juice containing drinks and tomato products, such as tomato juice and canned tomatoes. Spoilage is characterised by a medicinal smell and guaiacol production. These endospore-formers have been shown to survive pasteurisation conditions of 95 °C for 2 min, grow at temperatures between 25° and 60 °C and a pH range of 2.5 to 6.0. Knowledge of this organism is limited, both locally and internationally and the route of contamination to the final product is not well established. In this study the fruit concentrate processing environment was investigated as a potential source and route of contamination for the final product. Species of Alicyclobacillus were isolated from orchard soil, various stages during processing and from fruit juice and concentrates. The isolates were identified based on morpholological, biochemical and physiological properties. Identification to species level was done by 16S ribosomal RNA gene sequencing and strain differentiation by RAPD-PCR. Results indicate that species of A. acidoterrestris and Alicyclobacillus acidocaldarius were found in orchard soil and throughout the processing environment. This is the first report on the isolation of these species from orchard soil, vinegar flies and the fruit processing environment. The 16 isolates identified as A. acidoterrestris grouped into four clusters based on RAPD-PCR banding patterns, suggesting that they belong to at least four genotypic groups. Isolates from the fruit concentrate, wash water and soil located outside of the fruit processing plant grouped into one cluster. Concluded from these results, A. acidoterrestris found in the wash water and soil outside of the factory could act as a potential reservoir of organisms for the contamination of the final fruit concentrate. Thus good manufacturing practices play an essential role in controlling incidence of spoilage caused by these bacteria. Fruit juices can be treated using ultraviolet (UV-C) light with a wavelength of 254 nm, which has a germicidal effect against micro-organisms. Alicyclobacillus acidoterrestris spores were inoculated into tap water, used wash water from a fruit processing plant and grape juice concentrate. Ultraviolet dosage levels (J L−1) of 0, 61, 122, 183, 244, 305 and 367 were applied using a novel UV-C turbulent flow system. The UV treatment method was shown to reliably achieve in excess of a 4 log10 reduction (99.99%) per 0.5 kJ L-1 of UV-C dosage in all the liquids inoculated with A. acidoterrestris. The applied novel UV technology could serve as an alternative to thermal treatments of fruit juices for the inactivation of Alicyclobacillus spores or in the treatment of contaminated processing wash water. Finally, the thermal inactivation at 95 °C for two strains of A. acidoterrestris isolated from contaminated fruit juice concentrates were investigated in a 0.1% (m/v) peptone buffer solution (pH 7.04) and grape juice (pH 4.02, 15.5 °Brix). The thermal inactivation of A. acidoterrestris spores followed first-order kinetics, suggesting that as the microbial population is exposed to a specific high temperature, the spores inactivated at a constant rate. D-values determined in the buffer solution were calculated to be 1.92 min and 2.29 min, while in grape juice D-values were found to be 2.25 min and 2.58 min for the two strains tested. From this study it is clear that the D-value is dependant on the strain tested, but also on the soluble solids of the solution the cells are suspended in. The results indicated that the spores of A. acidoterrestris isolated from South African fruit juice concentrate may survive after the pasteurisation treatment commonly applied during manufacturing. AFRIKAANSE OPSOMMING: Spesies van Alicyclobacillus is suur-tolerante en hittebestande bakterieë wat bederf veroorsaak in hitte-behandelde vrugtesappe wat teen kamertemperatuur gestoor word. Gedurende die afgelope dekade het Alicyclobacillus spp. ‘n belangrike oorsaak van bederf in gepasteuriseerde vrugtesappe geword en beduidende ekonomiese verliese wêreldwyd veroorsaak. Bederf is aangeteken in appel-, peer-, lemoen-, perske-, mango- en witdruiwesap, sowel as in vrugtesapversnitte, vrugtesapbevattende drankies en in tamatieprodukte soos tamatiesap en ingemaakte tamaties. Bederf word gekenmerk deur ’n medisinale reuk en guaiacol produksie. Daar is gevind dat hierdie endospoorvormers pasteurisasie teen 95 °C vir 2 min kan oorleef en kan groei by temperature tussen 25° en 60 °C en ‘n pH van 2.5 to 6.0. Plaaslik sowel as internasionaal is kennis van hierdie organisme beperk en die roete van kontaminasie van produkte is nog nie goed vasgestel nie. In hierdie studie is die vrugtekonsentraat-verwerkingsmilieu ondersoek as ‘n moontlike bron en roete van kontaminasie van die finale produk. Spesies van Alicyclobacillus is vanuit vrugteboordgrond, verskeie verwerkingstadia en van vrugtesap en vrugtesapkonsentraat geïsoleer. Die isolate is op grond van morfologiese, biochemiese en fisiologiese eienskappe geïdentifiseer. Identifikasie tot spesiesvlak is deur 16S rDNS sekwensering gedoen en stam differensiasie deur RAPD-PKR. Resultate het aangetoon dat A. acidoterrestris en A. acidocaldarius in vrugteboordgrond sowel as in alle stadia van die verwerkingsmilieu voorkom. Dit is die eerste verslag van die isolering van hierdie spesies uit die Suid-Afrikaanse vrugteverwerkingsmilieu, vrugteboordgrond en asynvlieë. Die 16 isolate, geïdentifiseer as A. acidoterrestris en in vier groepe geplaas op grond van hul RAPD-PKR bandpatrone, dui aan dat hulle aan minstens vier genotipiese groepe behoort. Isolate afkomstig van die vrugtekonsentraat, waswater en die grond buitekant die vrugteverwerkingsaanleg het een groep gevorm. Uit hierdie resultate kan afgelei word dat A. acidoterrestris, wat in die waswater en grond buite die aanleg voorkom, as ‘n moontlike bron van organismes vir die kontaminering van die finale vrugtekonsentraat kan dien. Goeie vervaardigingspraktyke speel dus ‘n noodsaaklike rol in die beheer van bederf veroorsaak deur hierdie bakterieë. Vrugtesappe kan behandel word met ultravioletlig (UV-C) met ‘n golflengte van 254 nm wat ‘n dodende effek op mikro-organismes het. Kraanwater, gebruikte waswater van ‘n vrugtesapvervaardigingsaanleg en druiwesapkonsentraat is met A. acidoterrestris spore geïnokuleer. Ultraviolet toedieningsvlakke (J L−1) van 0, 61, 122, 183, 244, 305 en 367 is aangewend met behulp van ‘n nuwe UV-C drukvloei stelsel. Daar is aangetoon dat die UV-behandelingsmetode ‘n betroubare vermindering (99.99%) van meer as 4 log10 per 0.5 kJ L-1 van ‘n UV-C dosis gee in al die vloeistowwe wat geïnokuleer is met A. acidoterrestris. Die toegepaste nuwe UV-tegnologie kan gebruik word as ‘n alternatief tot die hittebehandeling van vrugtesap vir die deaktivering van Alicyclobacillus spore of in die behandeling van gekontamineerde waswater. Ten slotte is hitte-deaktivering teen 95 °C van twee stamme van A. acidoterrestris, geïsoleer uit gekontamineerde vrugtesapkonsentraat, in ‘n 0.1% (m/v) peptoonbufferoplossing (pH 7.04) en druiwesap (pH 4.02, 15.5 °Brix), ondersoek. Die hitte-deaktivering van A. acidoterrestris spore het eerste-orde kinetika gevolg, wat aandui dat die mikrobe-populasie teen ‘n konstante tempo afsterf, wanneer blootgestel aan ‘n spesifieke hoë temperatuur. Die D-waardes in die bufferoplossing is bereken as 1.92 min en 2.29 min, terwyl daar gevind is dat die D-waardes in druiwesap 2.25 min en 2.58 min is vir die twee betrokke stamme. Vanuit hierdie studie is dit duidelik dat die D-waardes afhang van die betrokke stam, maar ook van die oplosbare vaste stowwe van die oplossing waarin die selle opgelos is. Die resultate dui daarop dat die spore van A. acidoterrestris, wat geïsoleer is uit Suid-Afrikaanse vrugtesapkonsentraat, die pasteurisasiebehandeling wat algemeen tydens vervaardiging toegepas word, kan oorleef. Aangesien die toepassing van strenger hittebehandeling om spore van A. acidoterrestris te deaktiveer onaanvaarbare organoleptiese veranderinge in die produk tot gevolg het, word dit aanbeveel dat die risiko van bederf verminder behoort te word deur die gebruik van goeie vervaardigingspraktyke gedurende vrugteverwerking.

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Karacabey, Erkan. "Grape Juice Filtration, Thermopyhsical Properties Of Clear Fruit Juices And Pressurized Low Polarity Water (plpw) Extraction Of Polyphenolic Compounds From Grape Canes." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610989/index.pdf.

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Filtration of grape juice was investigated. Effects of process parameters of filtration were examined. The usage of precoating material and filter aid were found to be necessary to prolong the filter life. Filter cake was found to be incompressible with the effect of increasing pressure. Increase in temperature caused increase in flow rate due to the reduction in viscosity. The influences of depectinization and clarification on filtration process were also examined. Depectinization and clarification decreased the resistance and increased the flow rate. Improvement in the quality of the grape juice was observed when these pretreatments were employed. The effects of temperature and soluble solid concentration on physical properties of clarified fruit juices were investigated. High temperature and soluble solid content dependencies of density, viscosity and heat capacity were detected. Experimental data were fitted as a function of temperature and soluble solid content. Models being valid for studied clarified fruit juices were achieved for density and viscosity with the regression coefficients (R2) higher than 0.90. Optimization of the solid-liquid extraction conditions for trans-resveratrol, trans-&amp #949 -viniferin, ferulic acid, and total phenolics from milled grape canes has been investigated. Temperature and ethanol concentration were found to be major process variables for all responses. Maximum yields of trans-resveratrol, trans-&amp #949 -viniferin, ferulic acid, and total phenolics were predicted as 4.25 mg/g dw, 2.03 mg/g dw, 1.05 mg/g dw, and 9.28 mg/g dw, respectively. Optimization of extraction conditions for antioxidant activity of grape cane extracts measured by the Trolox equivalent antioxidant capacity (TEAC) and the oxygen radical absorbance capacity (ORACFL) assays was carried out using solid-liquid extraction and response surface methodology. Ethanol concentration and temperature employed for the extraction of antioxidant agents from grape cane samples were found to be statistically significant process variables affecting antioxidant activity measured by the TEAC and ORAC methods. trans-Resveratrol and trans-&amp #949 -viniferin were extracted from milled grape canes using pressurized low polarity water (PLPW). The extraction temperature was significant for both compounds: extraction at 160oC resulted in a 40% loss of trans-resveratrol compared to 95oC while reduction of trans-&amp #949 -viniferin at both temperatures remained at 30%. Increasing ethanol concentration from 0 to 25% increased the extraction of total phenolics and trans-&amp #949 -viniferin by 44% and 489%, respectively. Solvent flow rate also influenced trans-&amp #949 -viniferin extraction. Effective diffusivities of trans-resveratrol increased by three times with increasing temperature. The modified Gompertz equation satisfactorily explained the extraction of the stilbenes investigated.

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Srisukchayakul, Pornpoj. "Effects of acid adaptation on the survival of Lactobacillus plantarum NCMIB 8826 in fruit juices." Thesis, University of Reading, 2017. http://centaur.reading.ac.uk/76117/.

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The aims of this work were to study the effect of acid adaptation on the survival of the stationary phase Lactobacillus plantarum NCMIB 8826 cells, a model potential probiotic strain, in several highly acidic fruit juices namely cranberry (pH 2.7), pomegranate (pH 3.5), and lemon & lime juices (pH 2.8) and to investigate the mechanisms involved in cellular response. The results indicated that exposure of the cells in both acidified solutions (buffers and de Man, Rogosa and Sharpe medium; MRS) adjusted to pH 6 to 3 by hydrochloric acid and citric acid for a short period of time significantly improved cell survival in the fruit juices, although the impact on cell viability was less than 107 CFU/ml for 6 weeks which was required for probiotic drinks. Furthermore, the prolonged exposure time (1 to 5 h) and low temperature (10 and 4 ο C) were used to enhance the cell viability of Lactobacillus plantarum NCMIB 8826 but the improvements by these techniques could not make it as a promising strain for probiotic drinks. Analysis of citric and lactic acids as well as γ-aminobutyric acid (GABA) indicated that the citrate fermentation pathway and the glutamate decarboxylase system, which have been implicated in acid response in several lactobacilli, were not involved in this case while the analysis of the cellular fatty acid content showed that the cyclopropane fatty acid, cis-11,12-methylene octadecanoic acid (C19cyclow7c), significantly increased (by ∼1.7 fold) during acid adaptation, which was accompanied by a significant upregulation of the cyclopropane synthase (cfa) gene (by ∼12 fold), as demonstrated by reverse transcription polymerase chain reaction. It was likely that these changes led to a decrease in membrane fluidity and to lower membrane permeability, which prevent the cells from proton influx during storage in fruit juices. Examination of the cell morphology by cryo-scanning electron microscopy revealed that the cell surface of acid adapted cells was rougher and thicker compared to control cells, suggesting that the composition and structure of the peptidoglycan was possibly modified during acid exposure. A significant finding of this study was the observation that alanine, which represented the most abundant intracellular amino acid (> 45%), was significantly reduced in the case of acid adapted cells (∼20%) compared to control cells, which coincided with a significant decrease in the extracellular alanine (~10%). It seems, therefore, likely that upon acid adaptation the cells utilized the available alanine to increase in the D-alanylation of wall teichoic acid, resulting in a positive cell wall with enhanced ability to reduce the influx of protons during storage in fruit juices. Moreover, proteomic analysis was also performed using 2D-gel electrophoresis, which led to the identification of eight proteins exhibiting a difference in % volume of at least 1.4 in expression levels between acid adapted and control cells. Among these, five proteins, molecular chaperone GroEL, aminopeptidase C, 30S ribosomal protein S1, D-alanine-Dligase, and UPF0356 protein Ip_2157 were upregulated, whereas three proteins, 30S ribosomal protein S2, aspartate semialdehyde dehydrogenase, and the hypothetical protein HMPREF0531_11643 were downregulated in acid adapted cells compared to control cells.

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Fajtl, Zdeněk. "Study of qualitative parameters of fruit juices and possibilities of their modification via technological modifications." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2015. http://www.nusl.cz/ntk/nusl-217155.

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Ovocné šťávy jsou celosvětově nejoblíbenějšími nealkoholickými nápoji. Kromě vitamínů a minerálů jsou také bohatým zdrojem polyfenolů, které jsou považovány za látky přispívající k celkové antioxidační aktivitě. Zvyšující se požadavky konzumentů na kvalitu a bezpečnost potravin nutí výrobce k zvyšování výrobních a kvalitativních standardů potravin. Nedávné inovace ve výrobě ovocných šťáv vedly k modifikacím výrobních podmínek, které zahrnují změny ve složení šťávy (např. přídavek ovocné dužiny nebo malých ovocných kousků), vylepšování vlastností obalových materiálů a modifikace produkční atmosféry. Cílem diplomové práce bylo pomocí metod EPR a UV-VIS spektroskopie posoudit vliv různých výrobních postupů na vybrané kvalitativní znaky (antioxidační aktivita, změna barvy a koncentrace vybraných fytochemikálií) pomerančových šťáv s dužinou a ananasových šťáv, a charakterizovat jejich změny v průběhu dlouhodobého skladování. Získané výsledky byly zpracovány metodami multivariační statistické analýzy s cílem posoudit vliv původu suroviny, roku produkce a použitých výrobních podmínek na sledované parametry a celkovou kvalitu ovocných džusů. Výsledky jasně prokázaly, že pasterizace ovlivňuje kvalitu výrobku; ačkoli byla použita „šetrná“ pasterizace, byl u těchto vzorků pozorován mírný pokles prakticky všech monitorovaných parametrů v porovnání s čerstvými – nepasterizovanými šťávami. Avšak pokud jde o po-pasterizační změny, byl prokázán významný vliv produkční atmosféry na monitorované kvalitativní parametry šťáv, prokazující, že náhrada kyslíku inertními plyny může výrazně prodloužit trvanlivost šťáv. Kinetické studie změn sledovaných parametrů na době skladování ukazují, že ve většině případů dochází k postupnému zhoršování všech monitorovaných parametrů, a to bez ohledu na technologii zpracování šťávy. Ve vzorcích vyrobených použitím modifikované atmosféry bylo, v závislosti na typu inertního plynu, pozorováno zpomalení poklesu jednotlivých kvalitativních parametrů šťáv jako výsledek aplikace inertní atmosféry. Tento trend byl zřejmý především pro delší skladovací období, zatímco na začátku skladování (6 - 7 týdnů po výrobě dané šťávy) byly pozorované trendy nejednoznačné. Lze proto předpokládat že tento „ochranný“ efekt inertní atmosféry je ovlivňován fyzikálně-chemickými vlastnostmi jednotlivých plynů, zejména jejich rozpustností v kapalném médiu. Výsledky také prokázaly že vlastnosti šťáv jsou ,bez ohledu na druh ovoce, výrazně ovlivňovány také sezónními vlivy a původem surové šťávy. Z výsledků statistické analýzy vyplývá, že rok výroby je silným diskriminačním faktorem. Na základě všech monitorovaných charakteristik, bylo dosaženo absolutní diskriminace vzorků pomocí kanonické diskriminační analýzy. Pokud jde o původ surovin, byla dosažena pouze částečná diferenciace, i když s poměrně vysokým klasifikačním skóre. Pokud jde o technologii výroby, byla dosažena pouze částečná diferenciace vzorků podle typu použitého inertního plynu. Získané poznatky pomohou výrobcům ovocných šťáv s optimalizací výrobních podmínek s cílem získat výrobek s maximem prospěšných vlastností, které by si udržel po celou dobu expirace, jejíž délka může být také optimalizovány na základě prezentovaných výsledků.

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Moe, Sandar Tun Pornrat Sinchapanit. "Stability of vitamin C content in guava juices during pasteurization and storage at different conditions /." Abstract, 2007. http://mulinet3.li.mahidol.ac.th/thesis/2550/cd406/4838011.pdf.

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Duro, Debora. "The effect of a history of colic on carbohydrate absorption in infants consuming different fruit juices." FIU Digital Commons, 2000. http://digitalcommons.fiu.edu/etd/3109.

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The purpose of the research was to determine if a history of colic plays a role in carbohydrate absorption in infants consuming either apple or white grape juice. In this double-blind study, 31 infants (5.0 ± 0.4 months, 7.5 ± 0.9 Kg, 64.1 ± 3.8 cm, 29.2 ±3.4 % fat and 5.1 ± 0.6 Kg fat-free mass) were divided into four groups and were fed 120 ml of either white grape (sorbitol free;1:1 fructose to glucose ratio) or apple (sorbitol 0.5 g/dl; 2.3:1 fructose to glucose ratio) juice. Sixteen of the infants had a history of colic. During the study continuous physical activity (PA) and metabolic rate (MR) were measured for 0.5 hours before and 3.0 hours after juice load using an infant respiratory chamber. Carbohydrate absorption was determined every 30 minutes after juice feeding by breath hydrogen (BH2) gas analysis. Statistical differences between groups were determined by one way ANOVA and by independent t-test. Infants with history of colic and fed apple juice showed increased PA (p

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Kniel, Kalmia Elisabeth. "Evaluation of chemical treatments and ozone on the viability of Cryptosporidium parvum oocysts in fruit juices." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/27243.

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Cryptosporidium parvum is a protozoan parasite historically associated with waterborne and more recently foodborne outbreaks of diarrheal illness. Contamination of certain foods, such as unpasteurized apple cider, with infective oocysts may occur as oocysts are shed in the feces of common ruminants like cattle and deer that graze in and around orchards. Cryptosporidiosis can result in a severe illness for previously healthy individuals and a life-threatening illness in immunocompromised individuals. Disease occurs after the ingestion of small infective oocysts (4 to 5 mm in size). The relatively thick membrane of the oocysts allows them to be resistant to chlorine and many other environmental pressures, making oocysts difficult to inactivate. In this study, alternative treatments to pasteurization were evaluated for their ability to inhibit C. parvum oocyst viability in fruit juices. Oocyst viability was analyzed with a cell culture infectivity assay, using a human illeocecal cell line (HCT-8) that is most similar to human infection. The percent inhibition of infection by each treatment was determined along with the corresponding log reduction for the treatments found to be most effective. Infection by treated oocysts was compared to that of control untreated oocysts. Cell monolayers were infected with 10⁶ treated oocysts or a series of 10-fold dilutions. Parasitic life stages were visualized using an immunohistochemistry system and 100 microscope fields counted per monolayer. Organic acids and H₂O₂ were added on a wt/vol basis to apple cider, orange juice, and grape juices. Malic, citric, and tartaric acids at concentrations from 1%-5% inhibited C. parvum infectivity of HCT-8 cells by up to 88%. Concentrations ranging from 0.025%-3% H₂O₂ were evaluated where addition of 0.025% H₂O₂ to each juice resulted in a >5 log reduction of C. parvum infectivity as determined with an MPN-based cell culture infectivity assay. Treating apple cider, orange juice, and grape juice with ozone for a time period of 30 seconds up to 15 minutes at 6Â° and 22Â°C (0.9 g/L flow rate) inhibited C. parvum viability to > 90% as monitored in the cell culture assay. It is hypothesized that oocyst wall proteins that are necessary for infection are oxidized by the reactive oxygen species generated from the decomposition of the ozone and hydrogen peroxide treatments. These treatments or combinations thereof may offer potential alternatives to traditional pasteurization for fruit juices to successfully inhibit C. parvum viability. Ph. D.

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Hiremath, Nikhil Davangere. "Studies on high pressure processing and preservation of mango juice : pressure destruction kinetics, process verification and quality changes during storage." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82251.

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Thermal processing is the primary mode of preservation of mango products, which can be considerably damaging to the delicate quality of mango. HP processing could thus be a potential alternative for extending the shelf-life of mango products. Establishing HP processing technology need data on microbial inactivation kinetics and shelf-life study of the product. The objective of this research was therefore to evaluate the application of HP treatment for inactivation of microorganisms (pathogenic and spoilage type) and to evaluate the shelf-life of HP treated mango juice. HP destruction kinetics of three common spoilage microorganisms, Leuconostoc mesenteroides, Zygosaccharomyces bailii and Pichia membranaefaciens and two pathogenic microorganisms, Escherichia coli O157:H7 and Listeria monocytogenes Scott A, were evaluated at 250-550 MPa with 0-60 min holding time at room temperature with species specific initial counts between 10 6 to 108 CFU/mL.

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Dias, Rita Alvarenga Vieira. "Sumos de fruta naturais: características físico-químicas e sensoriais." Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/4202.

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Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia Considering the market’s potential growth of the natural fruit juices, this paper focuses on the study of four of these products. Since the microbiological quality of these juices is guaranteed, this work concentrates on the study of the physical, chemical and sensory characteristics of the juices. It was intended to assess the impact of the thermal shock and the cooling time of storage on the quality of the juice. For this study we analyzed four C-Optima juices (Mild Orange, Tropical Orange, Strawberry Banana and Red Berries). The samples were analyzed before and after the pasteurization and after 7, 14, 21, 28 and 35 days of refrigerated storage for the following parameters: pH, acidity, soluble solids, CIELab color and viscosity. The analysis of the results shows that the most significant change concerning physical and chemical characteristics of the analyzed juices is due to thermal shock. The pasteurization treatment causes some changes in the CIELab color parameters. There are no significant change color in general samples of Mild Tropical Orange and Orange; however the samples of Red Berries Strawberry Banana become discolored. In general, the physical and chemical changes occurring during storage are not perceived sensorily, which reinforces the idea that the shelf life proposed by the industry is designed with a large margin of time.

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Kumbet, Yesim. "Investigation Of Antioxidant Activities Of Fruit Juices And Herbal Teas And Their Antimicrobial Effects On Proteus Mirabilis." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612442/index.pdf.

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Herbal teas and fruit juices used in our regular diet may have importance in the protective treatment of some infectious diseases. In this study, selected dietary beverages were investigated for their antioxidant capacities and antimicrobial activities against Proteus mirabilis, a well known bacteria in urinary tract infections. Herbal teas sage (Salvia fruticosa Mill), anise (Pimpinella anisum L.), rosehip (Rosa canina L.), camomile (Anthemis arvensis L.) and fruit juices grape (Vitis vinifera L.), orange (Citrus sinensis L.), peach (Prunus persica L.), and pomegranate (Punica granatum L.) were chosen as samples of regular diets. Selected fruit juices and aqueous infusion tea extracts, lyophilised to dryness, were used throughout this study. Antioxidant capacities of the extracts were carried out by using 2,2&rsquo -azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging (ABTS) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH) methods along with the determination of total phenolic compounds in the extracts. Antimicrobial activities of extracts were determined by disc diffusion test, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. Among the herbal teas, sage infusion extract has displayed the highest radical scavenging capacity with ABTS EC50 value of 5.152 mg/mL, DPPH EC50 value of 0.072 mg/mL and with its high phenolic content of 0.411 mg/mg gallic acid equivalence. Among the fruit juices pomegranate has revealed significantly high DPPH EC50 and TEAC values 0.924 mg/mL and 0.552 mmol/g, respectively. Peach juice has been found with the highest total phenolic amount of 0.067 mg/mg gallic acid equivalent. Antimicrobial activities of herbal teas were correlating with antioxidant capacity studies, whereas sage infusion tea extract exhibited 3 mg/mL of minimum inhibitory concentration (MIC) and 6 mg/mL of minimum bactericidal concentration (MBC). Rosehip was also found as an effective antimicrobial agent with a minimum inhibitory concentration value of 3 mg/mL. In the meantime, there was no significant difference in the zone inhibition of herbal tea infusion extracts. In case of fruit juices grape and pomegranate may be effective antimicrobials in P. mirabilis infections with 0.75 mg/mL MIC and 6 mg/mL MBC, respectively at the same time both juices revealed significantly high inhibition zones with 11 mm.

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Tajchakavit, Sasithorn. "Microwave heating of fruit juices, kinetics of enzyme inactivation/microbial destruction and evaluation of enhanced thermal effects." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0019/NQ44605.pdf.

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Louw, Cornelius Jacobus. "The application of a strategic repositioning model to ensure successful change at Ceres Fruit Juices (Pty) Ltd." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51939.

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Thesis (MBA)--Stellenbosch University, 2000. ENGLISH ABSTRACT: Change is inevitable in today's demanding and changing business world. For an organisation to strategise effectively, it needs a process that is systematic and planned to ensure that the company can compete successfully, please customers and achieve good business and financial performance. The first section of the study focuses on a literature overview with regards to strategic repositioning. A model will be developed that highlight the importance of certain key issues that must be present to ensure an effective and workable strategy. The overview will show that the common mistake that organisations make, is to look only at the external environment, without giving much attention to key internal issues. From the model it will become evident that issues such as the organisational statements, the culture of the organisation, the way change efforts are handlep and what a company does to become world-class, are critical to ensure successful strategic repositioning. The second half of the study focuses on the application of the strategic repositioning model that was developed, to Ceres Fruit Juices (Pty) Ltd. A complete analysis will be done on the organisation statements, as well as an assessment on the culture and how far Ceres Fruit Juices is towards becoming a world-class organisation. From the results it was evident that Ceres Fruit Juices (Pty) Ltd needs to map out all their change activities to ensure the reaching of its strategic objectives. AFRIKAANSE OPSOMMING: Verandering is onvermydelik in vandag se veeleisende en veranderende besigheidswêreld. Vir 'n organisasie om 'n effektiewe strategie daar te stel, is dit noodsaaklik dat 'n sistematiese en beplande proses gevolg word om te verseker dat 'n maatskappy suksesvol kan meeding, kliënte tevrede kan stel en goeie besigheids- en finansiële resultate kan behaal. Die eerste gedeelte van die studie fokus op 'n literatuur-oorsig rondom strategiese herposisionering. 'n Model sal ontwikkel word wat teenwoordig moet wees om 'n effektiewe en werkbare strategie daar te stel. Die oorsig sal verder uitwys dat die algemene fout wat maatskappye maak, is om slegs na die eksterne omgewing te kyk, sonder om aandag aan kritiese interne aspekte te gee. Vanuit die model sal afgelei word dat aspekte soos organisasie doelstellings, die kultuur van die organisasie, die manier hoe verandering hanteer word en eienskappe wat aanwesig moet wees om op wêreldstandaard te wees, krities is om suksesvolle strategiese herposisionering te verseker. Die tweede helfte van die studie fokus op die toepassing van die strategiese herposisioneringsmodel wat ontwikkel is, op Ceres Fruit Juices (Pty) Ltd. 'n Volledig ontleding sal gedoen word op die organisasie doelstellings, sowel as 'n beoordeling van die kultuur en hoe ver Ceres Fruit Juices Ipty) Ltd op die pad is om 'n wêreldklas onderneming te word. Afleidings wat gemaak is vanuit die resultate, toon duidelik dat die maatskappy 'n volledige plan moet opstel vir hulle verandering aktiwiteite om te verseker dat daar by die strategiese doelwitte uitgekom word.

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Conti, Maria Josiane. "Crescimento de Alicyclobacillus acidoterrestris em seis tipos de Sucos de frutas tropicais em diferentes temperaturas." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256578.

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Orientador: Fumio Yokoya Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos Made available in DSpace on 2018-08-22T20:33:42Z (GMT). No. of bitstreams: 1 Conti_MariaJosiane_M.pdf: 10300128 bytes, checksum: c571b2db431105550b581c8203ff0630 (MD5) Previous issue date: 2013 Resumo: O Alicyclobacillus acidoterrestris, é uma bactéria acidotermofílica, não patogênica, de origem ambiental. Este organismo é um potencial agente deteriorante em polpas e sucos de frutas ácidos. Devido à presença de endosporos de elevada resistência térmica, torna-se difícil sua inativação pelos tratamentos térmicos convencionais de pasteutização. Esta pesquisa visou extrair e processar termicamente o suco de seis tipos de frutas tropicais, de caráter ácido (abacaxi, acerola, caju, goiaba, manga e maracujá), e avaliar se estes apresentam condições para que o A. acidoterrestris se desenvolva em sua temperatura ótima (45°C) e também em temperatura de abuso de processamento (35°C), temperatura que favorece o crescimento de microrganismos mesófilos. Além disso, foi analisada a concentração mínima inicial, do microrganismo em estudo, capaz de sobreviver e se desenvolver no suco de manga, aquele que apresentou melhores condições de desenvolvimento na primeira fase do estudo. Neste estudo foi também incluída a análise qualitativa de guaiacol como indicador de deterioração. Foi preparada uma suspensão com a mistura de esporos de quatro cepas de A. acidoterrestris em mesma concentração, padronizada e inoculada nos sucos, previamente extraídos e tratados termicamente, apresentando carga inicial no suco de 102 UFC/mL. O desenvolvimento do microrganismo foi acompanhado através de plaqueamentos em meio de cultura próprio, por até 30 dias, ou até que atingissem uma contagem constante. Ao final, foram avaliados o desenvolvimento máximo da bactéria, em cada suco, na respectiva condição de cultivo, e o período que levou para atingir estes determinados valores. Apenas no suco de caju o pool de bactérias não apresentou desenvolvimento, no prazo máximo estipulado do ensaio (30 dias). O microrganismo apresentou desenvolvimento em todos os demais sucos, alcançando índices de produção de guaiacol e outros subprodutos Abstract: Alicyclobacillus acidoterrestris is an acidophilic bacterium, nonpathogenic, of environmental origin. This organism is a potential spoiler acid frutits, pulps and juices. Due to the presence of endospores of high heat resistance, it becomes difficult to inactivate it by pasteurization conventional thermal treatment. This research aimed to extract and process thermally the juice of six kinds of tropical fruit, acid character (pineapple, acerola, cashew, guava, mango and passion fruit) and to evaluate if these have conditions for Alicyclobacillus acidoterrestris to develop in optimum temperature (45°C) and also in processing abuse temperature (35°C). Besides, it was analyzed the minimum initial concentration of the microorganism under study, which is able to survive and develop in the mango juice, which presented better conditions of development, according to the first phase of the study. A suspension was prepared with the spores mixture of four strains of A. acidoterrestris in the same concentration, because in preliminary studies it was possible to verify that some strains did not develop in all types of juice. The suspension was standardized and inoculated into the previously extracted and heart treated juices, showing initial concentration of 102 CFU/mL in the juice. The development of the microorganism was accompanied through plating in specific culture medium, for around 30 days or until it reached a constant counting. In the end, bacterium maximum growth was evaluated in each juice, in its respective growing condition and the time it took to achieve these values. The pool of bacteria didn't grow only in the cashew juice. All other juices showed development of the microorganism, reaching production rates of guaiacol and other byproducts, in accordaner with to previous studies Mestrado Ciência de Alimentos Mestra em Ciência de Alimentos

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Vyčítalová, Lucie. "Izotopové složení některých ovocných džusů - autenticita z hlediska zastoupení deuteria pomocí SNIF-NMR." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2009. http://www.nusl.cz/ntk/nusl-216544.

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The deuterium content of sugar in fruits is influenced mainly by two factors – the botanical and also the geographical origin of the fruit. The information of the fruit origin is kept even after fermentation of the sugar, in the molecules of ethanol. The deuterium content on the methyl group of ethanol then varies depending upon the botanical origin of the fruit. SNIF-NMR (Site-specific Natural Isotope Fractionation – Nuclear Magnetic Resonance) is a specific method for determination of the deuterium isotopic ratio (D/H) in small molecules, e.g. ethanol. This isotopic technique is widely used for determination of sugar adulteration of fruit-based beverages (wines, fruit juices..). In this thesis, the authentic samples of five different fruits (apples, oranges, grapefruits, pineapples and grapes) available in the Czech market have been collected and analyzed by SNIF-NMR. The results are presented as well as the comparison to some commercially available fruit juices and nectars.

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Kuldiloke, Jarupan. "Effect of ultrasound, temperature and pressure treatments on enzyme activity and quality indicators of fruit and vegetable juices." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=96506722X.

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Dede, Saner. "Effect Of High Hydrostatic Pressure (hhp) On Some Quality Paraeters And Shelf-life Of Fruit And Vegetable Juices." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606513/index.pdf.

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The quality and shelf-life of pressure processed (150, 200 and 250 MPa at 25 and 35&deg C for 5, 10 and 15 minutes) orange, tomato and carrot juices were compared to fresh and thermally pasteurised (60&deg C for 5, 10 and 15 minutes and 80&deg C for 1 minute) juices. Treatments were capable of microbial inhibition of juices to non-detectable levels. The change in ascorbic acid content of HHP treated juices was not statistically significant (p&gt 0.05). Both heat treatments at 60 and 80&deg C, displayed a significant loss and induced a decrease in the free radical scavenging activity but was not affected by HHP treatments. Pressurization at 250 MPa at 35&deg C for 15 minutes and thermal pasteurization at 80&deg C for 1 minute and stored at 4 and 25&deg C for shelf-life analysis. HHP treated juices showed a small loss of antioxidants (below 10%) at both storage temperatures whereas the loss is higher (about 30%) in the heat treated juices through shelf life (30 days). The pressurized juices, stored at 25&deg C, contained ascorbic acid better than heat treated ones after 30 days. The total color changes were minor (&amp #8710 E=10) for all pressurized juices but for heat pasteurized samples, higher as a result of insufficient antioxidant activity. The pH of juices was not affected by treatment, storage temperature or time. HHP yielded a better product, regarding the studied parameters of the juices compared to the conventional pasteurization. Therefore, HHP treatment (250 MPa, 35&deg C for 15 minutes) can be recommended for industrial production of fresh fruit and vegetables.

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Abountiolas, Marvin. "In Vitro and In Vivo Antioxidant Capacity of Synthetic and Natural Polyphenolic Compounds Identified from Strawberry and Fruit Juices." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6057.

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Strawberries can be considered a functional food because their consumption has been associated with several health benefits. They are important sources of bioactive compounds, such as vitamins and polyphenolic compounds, with recognized antioxidant capacity (AOC). However, strawberry overall quality and bioactive content are greatly affected by environmental conditions during pre- and post-harvest and, little is known about the stability of its bioactive compounds, specifically ascorbic acid (AA) and polyphenolics compounds. Furthermore, additional research that addresses the impact of polyphenolic compounds on in vitro and in vivo models is needed to understand the mechanisms behind their potential health benefits. Therefore, the objectives of the work presented in this thesis were to: 1) evaluate the impact of different disease control treatments on strawberry bioactive compounds and AOC; 2) understand the relationship between bioactive compounds and AOC in strawberries and fruit juices; 3) investigate the origin of AOC in strawberries by identifying their major polyphenolic compounds and, 4) explore the effects of polyphenol-rich fruits and fruit juices on the proliferation of cancer cells and lifespan of Caenorhabditis elegans. Conscientious consumers are aware of the health benefits of substantial fruit and vegetable consumption but are also concerned about the amount of pesticide residues that can be found in conventionally grown produce, with pesticide-free produce (i.e., organic) becoming more popular. However, the market price for organic strawberries can be more than twice that of conventionally grown fruit which discourages the average American from purchasing this fruit on a regular basis. Therefore, in the first study presented in this thesis, we hypothesized that reducing pesticide usage would provide the consumer with a “sustainable strawberry” that would have better or similar quality at a lower cost than organic fruit while it would also reduce environmental impact and risk to pesticide applicators. Results from this study showed that strawberries from a reduced fungicide treatment, had better or similar bioactive content and AOC than fruit from the conventional disease control treatment. After cold storage, strawberries from the reduced or conventional disease control treatments showed comparable amounts of bioactive compounds and AOC. These results indicate that growing strawberries with a reduced number of fungicide applications can be an alternative to the conventional disease control or organic practices as it may reduce residual fungicides in the fruit, decrease production costs while still retaining important bioactive compounds. In order to understand the relationship between bioactive compounds and AOC in strawberries and fruit juices, 56 different types of commercial beverages were chosen for the second study presented in this thesis. Overall, results showed that the higher the total phenolic contents (TPC) in the beverage the higher their AOC. Amongst all beverages studied, aronia, blackcurrant, and pomegranate juices contained the highest amount of TPC and AOC. Furthermore, after opening the bottles, these juices were maintained for 14 days at 4 °C, to test the stability of their TPC which was in general relatively stable throughout storage. Further investigation on individual polyphenolic compounds and their possible contribution to the overall AOC of fruits and fruit juices, led to a third study. Overall, results showed that the AOC of major individual polyphenolic compounds found in strawberries (i.e., pelargonidin, cyanidin, ellagic acid, quercetin, kaempferol, catechin, epicatechin, caffeic acid, p-coumaric acid, ferulic acid) was significantly higher than that of mixtures of the same compounds. In addition, the AOC of strawberries correlated with its major bioactive compounds (i.e., polyphenolic compounds and ascorbic acid) in a form of a synthetic bioactive strawberry model (“Powerberry”) composed of major strawberry polyphenolic compounds, vitamin C, fructose and glucose in the same ratios found in a real strawberry. These results suggest that even though strawberries contain many different polyphenolic compounds and vitamins, their AOC might only depend on few compounds that are found in significant quantities in the fruit. Finally, using cell and worm models we were able to demonstrate that conventional and organic strawberry, raspberry and blueberry fruits, and aronia, blackcurrant and pomegranate juices successfully inhibited the proliferation of HeLa cervical cancer cell lines. In addition, when introduced in low doses (0.75 mg ml-1 or lower) to the C. elegans diet, aronia, blackcurrant and pomegranate juices promoted longevity. Overall, results suggest that using whole fruit or fruit juices might constitute an alternative of treating cancer cells in vivo and that polyphenolic compounds contained in fruits and fruit juices displayed significant bioactivity in a worm model.

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Byarugaba-Bazirake, George William. "The effect of enzymatic processing on banana juice and wine." Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/1633.

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Truong, Vy Thuy. "Effect of cinnamic acid-cyclodextrin inclusion complexes on populations of Escherichia coli O157:H7 and Salmonella enterica in fruit juices." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/35622.

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Cinnamic acid (CA) is a naturally occurring organic acid that is found in some fruits and a number of spices. CA has antimicrobial activity against certain spoilage microorganisms and pathogenic bacteria. However, the acid is poorly soluble in water. Cyclodextrin molecules have a hydrophobic cavity that allows them to serve as a host for insoluble molecules in aqueous matrices. This study was conducted to determine if the aqueous solubility of cinnamic acid could be improved via complexation with Î±- or Î²-cyclodextrins, and if these complexes could be used to control bacterial pathogens in juices. Based upon phase solubility analysis, Î±-cyclodextrin was chosen as the host molecule for the remainder of this study. In complex with Î±-cyclodextrin, the solubility of cinnamic acid increased from approximately 400 mg/L to 3800 mg/L. Prepared cinnamic acid complexed with Î±-cyclodextrin was aseptically added (400 mg/L and 1000 mg/L) to orange juice inoculated with a Salmonella enterica (7 log CFU/mL) and apple cider inoculated with Escherichia coli O157:H7 (7 log CFU/mL). Cider and orange juice samples were extracted on day 0 and at 24 h intervals for seven days and spread plated onto Tryptic Soy Agar. Cinnamic acid was effective for reducing populations of both bacterial pathogens in juice. Populations of E. coli O157:H7 in the apple cider were significantly reduced after 7 days at 25.6 Â± 0.42Â° C at concentrations of 400 mg/L (5-log CFU/mL reduction) and 1000 mg/L (6-log CFU/mL reduction) cyclodextrin-cinnamic acid. S. enterica counts were also reduced in orange juice at 4Â° C treated with 400 mg/L (2.7-log CFU/mL reduction) and 1000 mg/L (3.2-log CFU/mL reduction) complexed cinnamic acid. The much improved solubility of this compound provides food processors with greater flexibility in using cinnamic acid in their product formulations. Master of Science

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Aykas, Didem P. "Verification of Ingredient Labels in High-Risk Oils and Fruit Juices by Using Vibrational Spectroscopy Combined with Pattern Recognition Analysis." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555644726731438.

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Visser, Cecilia Elaine. "Acceptability, choice and preference of brands and flavours of dairy fruit beverages by black female consumers." Diss., Pretoria ; [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-07032007-122455.

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Rouquié, Camille. "Microfiltration de jus de fruits et suspensions à base de fruits : faisabilité et performances d'une filtration par membranes immergées." Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTG041/document.

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La microfiltration est largement utilisée pour la clarification, la stabilisation et la concentration de nombreuses suspensions à base de fruits (jus de fruits, agro-déchets, vin, etc.). Malgré ses divers avantages, la microfiltration présente néanmoins un inconvénient majeur qui est le phénomène de colmatage qui s’installe pendant l’opération de filtration et entraîne une diminution de la perméabilité membranaire. Si de nombreux mécanismes de colmatage (adsorption, blocage de pores, etc.) sont observés pendant la filtration de suspensions polydisperses comme les jus de fruits ou certains coproduits liquides, le dépôt de particules sur la membrane est souvent supposé être le mécanisme limitant. La formation de ce dépôt est fortement dépendante de l’équilibre entre forces convectives (imposées par le flux de perméat), qui attirent les particules de la suspension à proximité de la membrane, et forces de rétrotransport, qui éloignent les particules de la surface membranaire. La stratégie la plus employée pour maitriser le colmatage membranaire par dépôt est la filtration tangentielle qui permet d’imposer de forts cisaillements à la surface membranaire qui favorisent les mécanismes de rétrotransport des particules. Si cette stratégie de maîtrise du colmatage est amplement utilisée à l’échelle industrielle pour la microfiltration des suspensions à base de fruits, elle nécessite des coûts d’investissement et de fonctionnement non négligeables qui limitent son implantation aux industries présentant de fortes capacités de production et d’investissement. Au regard de cela, l’utilisation d’une configuration de filtration à membranes immergées pour la microfiltration de suspensions à base de fruits pourrait être une alternative intéressante. Cette configuration repose sur l’immersion de la membrane (modules plans ou fibres creuses) dans la suspension à filtrer, et est associée à un mode de filtration externe-interne, frontal ou quasi-frontale. Si l’absence de conditions hydrodynamiques intenses au voisinage de la membrane est associée à des flux relativement bas, les nombreux avantages de ce mode opératoire (coûts de fonctionnement réduits, simplicité opérationnelle, forte compacité, etc.) pourraient favoriser son emploi par les petits producteurs de jus de fruits et/ou les industries de valorisation des coproduits présentant des capacités limitées d’investissement et enclins à minimiser leurs couts opérationnels. Ce travail a ainsi étudié pour la première fois la possibilité d’utiliser un tel système pour la microfiltration de suspensions à base de fruits variées (jus de fruits et coproduits vinicoles). Ce travail de thèse a ciblé ainsi plusieurs objectifs : (i) caractériser le potentiel et le comportement colmatant de suspensions à base de fruits, en lien avec les caractéristiques physicochimiques propres à chaque suspension et au regard de leur filtration par membranes immergées, (ii) étudier des performances d’un système de microfiltration de suspensions à base de fruits par membranes immergées, performances en termes de productivité et de sélectivité et enfin (iii) dégager des pistes de réflexion qui conduiraient à une choix pertinent de conditions de filtration (mode immergé ou tangentiel) pour un type de suspension ciblé. Ce travail fournit ainsi des résultats d’identification de paramètres physico-chimiques clefs qui pourraient constituer un premier guide pour le choix de la configuration membranaire la plus adaptée au produit, permettant d’assurer une productivité acceptable lors de la microfiltration de suspensions à base de fruits Microfiltration is widely used to ensure clarification, stabilization, and concentration of various fruit-based suspensions (e.g. fruit juices, food by-products, wine). However, the performances of membrane filtration remain highly challenged by membrane fouling. During microfiltration of polydisperse suspensions, such as fruit-based suspensions, membrane fouling is generally associated to the deposition of particles on the membrane layer. This type of fouling is mainly governed by the equilibrium between convective forces (permeate flow), leading particles to flow towards the membrane, and back-transport forces, removing particles away from the membrane surface. The filtration performances depend strongly on this equilibrium, which is mostly governed by the hydrodynamic conditions of the filtration process and the particles size distribution of the suspension. In food industries, cross-flow microfiltration is generally used to limit membrane fouling. In this configuration, high cross-flow velocities are applied in order to enhance the back-transport forces limiting the deposition of foulant materials on the membrane surface. However, this working mode is well known to be highly energy consuming and might not always be relevant depending on the suspension characteristics. In the light of this, using immersed membranes configuration for the microfiltration of fruit-based suspensions might be an interesting alternative, especially for small producers with limiting investment capacity. In this configuration, widely used in other fields, the membranes are immersed in the suspension and filtration is performed in operating conditions close to that of dead-end filtration with limited back-transport forces and low operating costs. However, the performances of this filtration configuration remain little studied for the microfiltration of fruit-based suspensions. In this respect, this work investigated for the first time the possibility of using immersed membranes configuration for the microfiltration of various fruit-based suspensions (fruit juices and winery byproducts). Firstly, a characterization of the fouling potential of various suspensions during their microfiltration using immersed membranes filtration was performed in relation with their physicochemical properties (particle size distribution). Then, this work allowed highlighting the promising performances of immersed membranes configuration when used for the microfiltration of fruit-based suspensions, in terms of productivity and in terms of selectivity (clarification, concentration of bioactive compounds). Finally, it allowed drawing preliminary results about the relation between the physicochemical characteristics of a suspension and its fouling behavior while using (i) immersed membranes filtration or (ii) conventional cross-flow filtration. These results might be of great interest for the identification of relevant physicochemical parameters to predict the usefulness of using high cross-flow velocity to prevent membrane fouling during the microfiltration of fruit-based suspensions

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Freitas, Vitória Matos de. "Estudos das alterações do suco de maracujá integral em embalagem do tipo pet e vidro." reponame:Repositório Institucional da UFC, 2007. http://www.repositorio.ufc.br/handle/riufc/18638.

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FREITAS, Vitória Matos de. Estudos das alterações do suco de maracujá integral em embalagem do tipo pet e vidro. 2007. 75 f. Dissertação (Mestrado em tecnologia de alimentos)- Universidade Federal do Ceará, Fortaleza-CE, 2007. Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-07-01T18:33:06Z No. of bitstreams: 1 2007_dis_vmfreitas.pdf: 314304 bytes, checksum: 83dd72dcc6903444ed58740bed70c6ca (MD5) Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-07-21T20:24:38Z (GMT) No. of bitstreams: 1 2007_dis_vmfreitas.pdf: 314304 bytes, checksum: 83dd72dcc6903444ed58740bed70c6ca (MD5) Made available in DSpace on 2016-07-21T20:24:38Z (GMT). No. of bitstreams: 1 2007_dis_vmfreitas.pdf: 314304 bytes, checksum: 83dd72dcc6903444ed58740bed70c6ca (MD5) Previous issue date: 2007 In Brazil, is traditional the consumption of plain tropical fruit juices bottled in glass or PET materials. The packaging materials are essential to protect the food product and to preserve its inherent quality during the storage. However sorption phenomena from food to packaging materials and the migration phenomena from packaging to the food may alter the product’s sensory quality. The objective of the present work was to evaluate the stability of passion fruit juices bottled in glass (used as reference) and PET materials during 120 days storage, regarding to the volatile compounds profile, physicalchemical and sensory properties (aroma and flavor). Bottles from the same production batch were purchased in local supermarkets (Fortaleza-CE, Brazil) and submitted to chemical, sensory and chromatographic analyses. Juices were characterized by determination of pH, soluble solids, total titrable acidity, ascorbic acid, color, total and reducing sugars. The characteristic passion fruit aroma and flavor were evaluated by a trained panel with a nine-cm nonstructured scale. The volatile compounds were isolated using a dynamic headspace technique by suction, in Porapak Q, analyzed by high resolution gas chromatography (FID) and identified by GC-MS. Five odoriferous compounds, according to the literature, were monitored: E-3-hexenol (passion fruit, fruity), Z- 3-hexenol (passion fruit, green), ethyl butanoate (fruity, sweet), ethyl hexanoate (fruity, sweet) and benzaldehyde (green). Both juices showed good chemical stability during the storage period, with the exception of ascorbic acid which reduced 58,20% and 39,12% in the glass and PET samples, respectively. The volatile compounds did not suffer consistent changes during storage, keeping its original passion fruit aroma and flavor intensities. In the PET stored samples, the compound ethyl butanoate showed a substantial reduction, which, nevertheless, was not enough to provoke significant changes in the product’s aroma and flavor within 120 days. No Brasil, é tradicional o consume de sucos integrais de frutas tropicais envasados em garrafas de vidro ou, mais recentemente, em embalagens de polietileno tereftalato (PET). Os materiais de embalagem são essenciais para proteger o produto alimentício e preservar sua qualidade durante a estocagem. No entanto, a sorção dos voláteis do alimento para a embalagem ou a migração de compostos da embalagem para o alimento podem alterar a qualidade sensorial do produto. Este trabalho teve como objetivo avaliar a estabilidade de sucos de maracujá envasados em garrafas de vidro (como referência) e PET durante 120 dias de armazenamento, em relação ao seu perfil de compostos voláteis, características físico-químicas e sensoriais (aroma e sabor). Garrafas de um mesmo lote de fabricação foram compradas em supermercados locais (Fortaleza-CE) e submetidos a análises químicas, sensoriais e cromatográficas. Os sucos foram caracterizados pela determinação do pH, sólidos solúveis, acidez total titulável, ácido ascórbico, cor, açúcares totais e redutores. O aroma e sabor característicos de maracujá foram avaliados por uma equipe treinada com uma escala não-estruturada de 9 cm. Os compostos voláteis foram isolados pela técnica de headspace dinâmico, por sucção, em Porapak Q, analisados por cromatografia gasosa de alta resolução e identificados por CG-espectrometria de massas. Cinco compostos odoríferos, segundo a literatura, foram monitorados: E-3-hexenol (maracujá, frutal), Z-3-hexenol (maracujá, verde), butanoato de etila (frutal, doce), hexanoato de etila (frutal, doce) e benzaldeído (verde). Ambos os sucos apresentaram boa estabilidade físico-química durante o período estudado, com exceção do ácido ascórbico que apresentou uma redução de 58,2% e 39,1% nas amostras da embalagem de vidro e de PET, respectivamente. Os compostos voláteis das amostras em vidro não variaram ao longo do período de estocagem, mantendo as intensidades originais de aroma e sabor do suco. No lote envasado em PET o composto butanoato de etila diminuiu ao longo do armazenamento, sem, no entanto, provocar alterações significativas na intensidade do aroma e sabor do produto, ao final de 120 dias.

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Astolfi, Filho Zailer. "Encapsulação de sucos de frutas por co-cristalização com sacarose /." São José do Rio Preto : [s.n.], 2003. http://hdl.handle.net/11449/90769.

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Orientador: Vânia Regina Nicoletti Telis Banca: Luis Alexandre Pedro de Freitas Banca: Célia Maria Landi Franco Resumo: A encapsulação de sucos concentrados de limão e maracujá pelo processo de co-cristalização com sacarose foi avaliada pela determinação de propriedades físicas e fisico-químicas dos produtos obtidos. O processo de co-cristalização foi conduzido a partir da concentração de um xarope de sacarose até a supersaturação, quando então era adicionado o material a ser encapsulado. A partir daí, a mistura era submetida a uma intensa agitação que induzia à nucleação e à aglomeração do produto. O objetivo principal do trabalho foi avaliar o efeito da produção de suco adicionada e do pH do suco sobre a umidade, solubilidade, densidade aparente e ângulo de repouso dos produtos obtidos. Também foram estudados o comportamento higroscópico e a cinética de degradação de vitamina C do material encapsulado, em função das variáveis citadas acima. Finalmente, pelo uso da calorimetria diferencial de varredura, foram obtidas informações a respeito da influência da proporção de suco e do pH sobre as transições de fase observadas e sobre a microestrutura dos produtos co-cristalizados. Os produtos obtidos apresentaram menores umidades em menores proporções de sucos e pHs e as densidades resultaram na faixa em que se encontram a maioria dos pós alimentícios. O tempo de solubilização foi menor em maiores proporções de suco e baixos pHs. Os ângulos de repouso dos produtos foram satisfatórios se comparados com a faixa em que se encontram os pós da matriz encapsulante. Os materiais menos hidroscópicos foram os preparados com menor quantidade de suco e em menores pHs. A degradação de vitamina C durante a armazenagem foi menos acentuada em baixas proporções de suco e em menores pHs, tendo o suco de maracujá... (Resumo completo, clicar acesso eletrônico abaixo) Abstract: Encapsulation of concentrated lemon and passion fruit juices by co-crystallization with sucrose was studied by determining physical and physicochemical properties of the obtained products. The co-crystallization was carried out by concentrating a sucrose syrup until supersaturation and, then, adding the core material. The mixture was submitted to an intensive mixing, which induced nucleation and product agglomeration. The main objective of this work was to evaluate the effects of the added proportion of juice and juice pH on moisture, solubility, apparent density, and repose angle of co-crystallized products. The hygroscopic behavior and ascorbic acid degradation of the encapsulated material as affected by the above variables were also studied. The product microstructure was investigated by differential scanning calorimetry and polarized light microscopy. Lower moisture was obtained with lower juice proportions and lower pHþs, and apparent densities resulted in the range of the majority of food powders. Solubility increased with higher juice proportion and lower pHþs, whereas repose angles were similar to those of the encapsulating matrix. Less hygroscopic materials were obtained with lower juice proportion and lower pHþs. The passion fruit product presented lower rates of vitamin C degradation and degradation rates decreased with decreasing juice proportions and pHþs. The DSC thermograms and polarized light micrographs showed that the encapsulating matrix and the co-crystallized products were in the crystalline state. Mestre

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43

Stojanovic, Jelena. "Determination of polyphenol oxidase (PPO) activity, anthocyanin contents and the phytonutrient changes in blueberry juice as influenced by different processing methods." Diss., Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-05292008-172900.

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Schurman, John Jackson. "Antibacterial Activity of Hydrogen Peroxide Against Escherichia Coli O157:H7 and Salmonella Spp. in Fruit Juices, Both Alone and in Combination With Organic Acids." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34302.

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The antibacterial efficacy of hydrogen peroxide treatments in four fruit juices was determined. Preservative free apple cider, white grape, and purple grape juice were inoculated with ~ 6.4 log CFU/ml of a five strain, acid adapted, nalidixic acid resistant E. coli O157:H7 cocktail. Orange juice was inoculated with a comparable Salmonella spp. cocktail. In the first study, 0.017% and 0.012% H2O2 was added in combination with 0.1% and 0.3% of the dominant organic acid (OA) to 4oC and 25oC juices, with samples taken each day for 21 days. H2O2 was a significant factor in all juices (p < 0.05) except white grape (lack of data), and both 0.017% H2O2 treatments reduced counts in apple cider, orange juice, and white grape to undetectable numbers within 48 hrs as cultured on tryptone soy agar + 0.05% nalidixic acid (TSAN). Treatments in purple grape juice were less effective overall, and more dependent on OA concentration (p < 0.001) than H2O2. There were instances where bacterial survival in apple cider, purple grape, and orange juice continued for 21 days after treatment, and sometimes outlasted the control. These occurrences were dependent on temperature (25oC) and H2O2 (0.012%), but not on OA. However, OA concentration was a significant factor (p < 0.05) overall in apple cider and purple grape juice, but not in orange juice. In the second study, 0.015% and 0.03% H2O2 was added to 10, 25, and 40oC apple cider and orange juice inoculated with 6.4 log CFU/ml E. coli O157:H7 and Salmonella spp. respectively. Only 0.03% H2O2 was effective in reducing counts to undetectable numbers in both juices. However, both temperature and H2O2 were significant factors (p < 0.0001) in bacterial destruction, with 0.03% H2O2 at 40oC giving undetectable numbers at < 3 and < 6 hours in orange juice and apple cider respectively. It has been demonstrated that at ~ > 0.017%, H2O2 can provide a 5 log reduction of these pathogens in fruit juice. Increasing temperature and organic acid concentration can improve its rate of effectiveness in certain juices. However, sensory concerns may negate its use in some products. Master of Science

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Freitas, VitÃria Matos de. "Estudos das alteraÃÃes do suco de maracujÃ integral em embalagem do tipo pet e vidro." Universidade Federal do CearÃ, 2007. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=1504.

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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico No Brasil, Ã tradicional o consume de sucos integrais de frutas tropicais envasados em garrafas de vidro ou, mais recentemente, em embalagens de polietileno tereftalato (PET). Os materiais de embalagem sÃo essenciais para proteger o produto alimentÃcio e preservar sua qualidade durante a estocagem. No entanto, a sorÃÃo dos volÃteis do alimento para a embalagem ou a migraÃÃo de compostos da embalagem para o alimento podem alterar a qualidade sensorial do produto. Este trabalho teve como objetivo avaliar a estabilidade de sucos de maracujÃ envasados em garrafas de vidro (como referÃncia) e PET durante 120 dias de armazenamento, em relaÃÃo ao seu perfil de compostos volÃteis, caracterÃsticas fÃsico-quÃmicas e sensoriais (aroma e sabor). Garrafas de um mesmo lote de fabricaÃÃo foram compradas em supermercados locais (Fortaleza-CE) e submetidos a anÃlises quÃmicas, sensoriais e cromatogrÃficas. Os sucos foram caracterizados pela determinaÃÃo do pH, sÃlidos solÃveis, acidez total titulÃvel, Ãcido ascÃrbico, cor, aÃÃcares totais e redutores. O aroma e sabor caracterÃsticos de maracujÃ foram avaliados por uma equipe treinada com uma escala nÃo-estruturada de 9 cm. Os compostos volÃteis foram isolados pela tÃcnica de headspace dinÃmico, por sucÃÃo, em Porapak Q, analisados por cromatografia gasosa de alta resoluÃÃo e identificados por CG-espectrometria de massas. Cinco compostos odorÃferos, segundo a literatura, foram monitorados: E-3-hexenol (maracujÃ, frutal), Z-3-hexenol (maracujÃ, verde), butanoato de etila (frutal, doce), hexanoato de etila (frutal, doce) e benzaldeÃdo (verde). Ambos os sucos apresentaram boa estabilidade fÃsico-quÃmica durante o perÃodo estudado, com exceÃÃo do Ãcido ascÃrbico que apresentou uma reduÃÃo de 58,2% e 39,1% nas amostras da embalagem de vidro e de PET, respectivamente. Os compostos volÃteis das amostras em vidro nÃo variaram ao longo do perÃodo de estocagem, mantendo as intensidades originais de aroma e sabor do suco. No lote envasado em PET o composto butanoato de etila diminuiu ao longo do armazenamento, sem, no entanto, provocar alteraÃÃes significativas na intensidade do aroma e sabor do produto, ao final de 120 dias. In Brazil, is traditional the consumption of plain tropical fruit juices bottled in glass or PET materials. The packaging materials are essential to protect the food product and to preserve its inherent quality during the storage. However sorption phenomena from food to packaging materials and the migration phenomena from packaging to the food may alter the productâs sensory quality. The objective of the present work was to evaluate the stability of passion fruit juices bottled in glass (used as reference) and PET materials during 120 days storage, regarding to the volatile compounds profile, physicalchemical and sensory properties (aroma and flavor). Bottles from the same production batch were purchased in local supermarkets (Fortaleza-CE, Brazil) and submitted to chemical, sensory and chromatographic analyses. Juices were characterized by determination of pH, soluble solids, total titrable acidity, ascorbic acid, color, total and reducing sugars. The characteristic passion fruit aroma and flavor were evaluated by a trained panel with a nine-cm nonstructured scale. The volatile compounds were isolated using a dynamic headspace technique by suction, in Porapak Q, analyzed by high resolution gas chromatography (FID) and identified by GC-MS. Five odoriferous compounds, according to the literature, were monitored: E-3-hexenol (passion fruit, fruity), Z- 3-hexenol (passion fruit, green), ethyl butanoate (fruity, sweet), ethyl hexanoate (fruity, sweet) and benzaldehyde (green). Both juices showed good chemical stability during the storage period, with the exception of ascorbic acid which reduced 58,20% and 39,12% in the glass and PET samples, respectively. The volatile compounds did not suffer consistent changes during storage, keeping its original passion fruit aroma and flavor intensities. In the PET stored samples, the compound ethyl butanoate showed a substantial reduction, which, nevertheless, was not enough to provoke significant changes in the productâs aroma and flavor within 120 days.

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Sandri, Ivana Greice. "Enzimas pectinolíticas : seleção de linhagens fúngicas produtoras, caracterização e aplicação em processos da indústria de alimentos." reponame:Repositório Institucional da UCS, 2010. https://repositorio.ucs.br/handle/11338/516.

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Nesse trabalho, isolados fúngicos obtidos de vegetais em decomposição foram testados quanto à sua capacidade de produzir pectinases aplicáveis ao tratamento enzimático de sucos de maçã e de mirtilo. Com base na secreção de endo-poligalacturonase (endo-PG), dois isolados identificados e denominados Aspergillus niger LB23 e Aspergillus fumigatus LB39J foram selecionados para uso em processos em estado sólido e submerso, respectivamente. Os extratos enzimáticos dessas linhagens não apresentam teores de aflatoxinas totais (B1, B2, G1, G2) até um limite de detecção de 2 μg/Kg. A preparação enzimática obtida em cultivo em estado sólido de A. niger LB23 apresentou maiores atividades de endo-PG e exo-poligalacturonase (exo-PG) em pH 4,0, enquanto a reação enzimática com os extratos enzimáticos obtidos em cultivos submersos de A. fumigatus LB39J foram favorecidos em pH entre 4,0 e 5,0, para endo-PG, e 5,0, para exo-PG. Com relação à temperatura de reação da preparação pectinolítica de A. niger LB23, endo e exo-PG mostraram melhores desempenhos nas faixas 40-50°C e 50-60°C, respectivamente. Para as poligalacturonases de A. fumigatus LB39J, definiu-se um intervalo entre 40 e 60°C, para endo-PG, e 60ºC, para exo-PG, como as melhores temperaturas. Quando a estabilidade térmica das poligalacturonases presentes em ambas as preparações foi avaliada, observou-se preservação de cerca de 70% das atividades após 150 minutos de exposição a temperaturas de até 40ºC. Foi avaliada a influência de diferentes concentrações de glicose e pectina sobre os resultados do processo em cultivos em estado sólido com A. niger LB23, sendo observado incremento das atividades de endo e exo-PG em meio com 6% (m/m) de pectina e isento de glicose, atingindo-se 65 unidades por grama de meio seco (U/g) e 198 U/g, respectivamente. Em cultivos submersos com A. fumigatus LB39J, maiores atividades foram obtidas em meio com 20 g/L de pectina e sem glicose: 42 U/mL de endo-PG e 32 U/mL de exo-PG. Nas condições definidas para o processo submerso, foram testados diferentes valores de pH inicial do meio. As máximas atividades foram observadas com pH inicial 3,0 para endo-PG (44 U/mL) e 4,0 para exo-PG (37 U/mL). Adicionalmente, em fermentador de bancada, constatou-se que um valor de pH inicial de 4,0, com o valor mínimo sem controle e, após, com o valor máximo controlado em 3,5, proporcionou as maiores atividades com 81 U/mL de endo-PG e 49 U/mL de exo-PG. Comparando-se os extratos enzimáticos produzidos pelas linhagens selecionadas, verificou-se que as pectinases produzidas por A. niger LB23 foram mais eficientes na hidrólise enzimática das substâncias pécticas presentes nos sucos de maçã e mirtilo, proporcionando, maior redução de turbidez (90 e 40%) e viscosidade (40 e 60%) e aumento na clarificação (90 e 55%). Esses resultados indicam o potencial das pectinases de A. niger LB23 para o tratamento enzimático de sucos de frutas, ressaltando-se que o teor de compostos fenólicos e a capacidade antioxidante dos sucos foram, em sua maior parte, preservados após o tratamento. Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-06-02T17:45:32Z No. of bitstreams: 1 Tese Ivana Greice Sandri.pdf: 1824755 bytes, checksum: c0fad543a60bbb77cd7beb3d28893487 (MD5) Made available in DSpace on 2014-06-02T17:45:32Z (GMT). No. of bitstreams: 1 Tese Ivana Greice Sandri.pdf: 1824755 bytes, checksum: c0fad543a60bbb77cd7beb3d28893487 (MD5) In this work, fungus samples isolated from decomposing vegetables were tested with respect to their capacity of producing pectinases to be applied to the enzymatic treatment of apple and bilberry juices. Taking in account the secretion of endo-polygalacturonase (endo-PG), two isolates which were identified and named Aspergillus niger LB23 e Aspergillus fumigatus LB39J were selected for solid-state and submerged cultivations, respectively. The enzymatic extracts from these strains did not present total aflatoxin (B1, B2, G1, G2) levels up to detection limit of 2 μg/Kg. The enzyme preparation obtained from solid-state cultivation of A. niger LB23 showed the largest activities of both endo-PG and exo-polygalacturonase (exo-PG) at pH 4.0, whereas the reaction with submerged A. fumigatus L39J enzymatic extracts was favoured at pH between 4.0 and 5.0 for endo-PG and 5.0 for exo-PG. With respect to the reaction temperature for A. niger LB23 pectinolytic preparation, endo and exo-PG showed the best performances at the ranges 40-50ºC and 50-60ºC, respectively. For A. fumigatus L39J polygalacturonases, a range from 40 to 60ºC, for endo-PG, and 60ºC, for exo-PG, were defined as the best temperatures. When the thermal stability of polygalacturonases present in both preparations was evaluated, preservation of about 70% of activities was observed after exposing the enzymes to temperatures up to 40ºC for 150 minutes. The influence of different glucose and pectin concentrations on the results of the solid-state process with A. niger LB23 was assessed and an increment in endo and exo-PG activities were observed in medium containing 6% (w/w) of pectin and absence of glucose, with activities of 65 units per gram of dry medium (U/gdm) and 198 U/gdm being achieved. In submerged cultivation of A. fumigatus LB39, highest enzyme activities were obtained in medium with 20 g/L of pectin and without glucose: 42 U/mL for endo-PG and 32 U/mL for exo-PG. In the conditions defined for the submerged process, different medium initial pH values were tested. Maximum activities were observed at initial pH of 3.0 for endo-PG (44 U/mL) and 4.0 for exo-PG (37 U/mL). Furthermore, in bench bioreactor, it was observed that an initial pH of 4.0, with uncontrolled minimum value and, afterwards, maximum value controlled at 3.5 led to the largest enzyme production with 81 U/mL of endo-PG and 49 U/mL of exo-PG. By comparing the enzymatic preparations produced by the selected strains, it was noticed that the pectinase produced by A. niger LB23 were more efficient for the hydrolysis of pectic substances present in both apple and bilberry juices, since it improved reduction of turbidity (90 and 40%) and viscosity (40 and 60%) and increasing clarification (90 and 55%), respectively. These results indicate the potential of A. niger LB23 pectinases for the enzymatic treatment of fruit juices, being remarkable that both the level of phenolic compounds and antioxidant capacity of juices were mostly preserved after treatment.

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Suh, Jin-Hyang. "Consumption of fruit juices and wines rich in polyphenols : potential health effects in oxidative stress animal models and roles of procyanidins, anthocyanins and ellagitannins." Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20230.

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On étudie les potentialités d'action de la consommation de jus de fruits et de vins riches en polyphénols sur modèle pathologique de stress oxydant, l'athérosclérose précoce, d'origine nutritionnelle, ainsi que leur effet protecteur spécifique vis à vis de cette pathologie. Dans une première partie expérimentale, nous avons analysé les polyphénols de trois variétés de jus de framboises (Cardinal, Glen Ample et Tulameen) et deux vins (Kaki et Merlot) par HPLC. Nous avons identifié et quantifié les composants phénoliques de la famille des anthocyanes et des ellagitanins, les deux constituants majeurs des polyphénols de framboise. Leurs compositions diffèrent significativement, en particulier entre Glen Ample et Tulameen. Concernant les vins, les flavan-3-ols (monomères et oligomères) ont été analysés. Les concentrations de chaque composant étaient fondamentalement différents entre les deux vins, sauf pour les dimères. Ceci nous a conduit à aborder l'étude in vivo sur hamster syrien doré recevant un régime riche en lipides et cholestérol, et carencé en antioxydants alimentaires. L'ingestion de Glen Ample (équivalent à 250 mL de jus de framboise par jour pour une homme de 70 kg) inhibe les facteurs pro-oxydants et améliore le statut antioxydant alors que le jus Tulameen a un effet protecteur contre la dyslipidémie. Ces effets peuvent être liés aux ellagitanins et anthocyanes respectivement. Nous avons montré que la consommation de vin à dose nutritionnelle (équivalent à 2 verres par repas pour un homme de 70 kg) améliorait la réactivité vasculaire, la dyslipidémie et le statut antioxydant. Parmi ces effets bénéfiques, aucune différence n'apparaît entre le vin de kaki et le Merlot, ce qui suggère que les dimères de procyanidines sont impliqués dans les effets biologiques des polyphénols The purpose of this study is to explore the potential of fruit juices and wines consumption rich in polyphenol on pathological models of oxidative stress, diet-induced early atherosclerosis, and to research their specific protective effect against the pathology.In the first part of this work we analyzed the polyphenols in three varieties of raspberry juices (Cardinal, Glen Ample and Tulameen) and two wines (Persimmon and Merlot) by HPLC. We identified and quantified phenolic components of anthocyanins and ellagitannins family, the two major constituents in raspberries polyphenols. Their compositions differed significantly especially between Glen Ample and Tulameen. For wines, flavan-3-ols (monomers and oligomers) were analyzed. Concentrations of each component were fundamentally different in two wines except for procyanidin dimers.These results led us to address in vivo studies on Syrian Golden hamsters fed a high-fat, high-cholesterol diet deprived in dietary antioxidants. Consumption of Glen Ample (equivalent to 250 mL of raspberry juice per day for a 70 kg human) inhibits pro-oxidant factors and improves antioxidant status whereas Tulameen shows a protective effect against dyslipidemia which may be due to its ellagitannins and anthocyanins respectively.Nutritional dose of wines (equivalent to 2 glasses of wine per meal for a 70 kg human) improves vascular reactivity, dyslipidemia and antioxidant status. No difference appeared between persimmon and merlot wine antioxidant properties suggesting that procyanidin dimers are implicated in the biological effects of polyphenols

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Saron, Elisabete Segantini 1968. "Estabilidade de suco de maracuja acondicionado em embalagens de aço com diferentes revestimentos organicos." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254417.

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Orientadores: Hilary Castle de Menezes, Silvia Tondella Dantas Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos Made available in DSpace on 2018-08-03T19:14:51Z (GMT). No. of bitstreams: 1 Saron_ElisabeteSegantini_M.pdf: 1585969 bytes, checksum: 62f0753fe79c5076a75df66de797a41a (MD5) Previous issue date: 2004 Resumo: Este estudo teve por objetivo avaliar diferentes especificações de envernizamento interno do corpo e da costura lateral de latas de folha-de-flandres de três peças, formadas por eletrossolda, no acondicionamento de suco de maracujá pronto para beber, por meio de teste de estocagem e avaliação do desempenho em relação à interação embalagem/alimento. Durante o estudo foram avaliados três sistemas de revestimento orgânico interno da embalagem, sendo o primeiro composto de verniz epóxi-fenólico líquido aplicado na folha plana e verniz epóxi-vinílico-acrilado líquido aplicado na região da solda; o segundo um verniz epóxi-fenólico líquido aplicado na folha plana, verniz epóxi-vinílico-acrilado líquido aplicado na solda e uma segunda camada de verniz epóxi modificado líquido, aplicado por spray após a formação da lata e o terceiro um verniz líquido epóxi-fenólico aplicado na folha plana e verniz poliéster em pó aplicado na solda, denominados latas Normal, Repair e Pó, respectivamente. As embalagens foram caracterizadas quanto ao tipo de material metálico (espessura, dureza e camadas de estanho e cromo), avaliação do fechamento (recravação), atendimento aos requisitos de embalagens para contato com alimentos previstos pela Legislação Brasileira e pelo MERCOSUL e caracterização dos revestimentos orgânicos do corpo, tampa, fundo e side stripe, em relação à camada seca, identificação, aderência, porosidade e grau de cura. O teste de estocagem foi realizado pelo período de 6 meses em duas condições de temperatura controlada, 25oC ± 2°C e 35oC ± 3oC, com avaliações periódicas a intervalos de 15 dias no primeiro mês, 30 dias no segundo mês e de 60 dias até completar 180 dias de estocagem. Os parâmetros de avaliação periódica foram aparência visual interna das latas, nível de vácuo, composição de gases (O2, N2, CO2 e H2) no espaço-livre da embalagem, avaliação sensorial, avaliação instrumental de cor, pH, acidez, estimativa dos sólidos solúveis (°Brix), concentração de ferro, estanho e cromo no suco de maracujá e conteúdo de vitamina C, sendo que este último foi determinado apenas ao zero dia, 15 e 180 dias de estocagem Abstract: The purpose of this study was to evaluate different specifications of welded three piece tinplate cans with respect to the internal body passion fruit juice. The evaluation was by a storage test, evaluating the performance relative to food/packaging interaction. Three systems of internal organic coatings of the cans were analyzed. The first was composed of a liquid epoxy-phenolic lacquer applied to the flat tinplate and liquid epoxyvinillic-acrylate lacquer applied to the side stripe. The second type was a liquid epoxyphenolic lacquer applied to the flat tinplate and a liquid epoxy-vinillic-acrylate lacquer applied to the side stripe and a second layer of liquid modified epoxy lacquer, applied by spraying after the formation of the can. The third type was a liquid epoxy-phenolic lacquer applied to the flat tinplate and a powdered polyester lacquer applied to the side stripe. The systems were denominated Normal, Repair and Pó, respectively. The cans were characterized according to the type of metallic material (thickness, hardness and tin and chromium layers), evaluation of the double seams, approval for contact with foodstuffs in accordance with the procedures and rules of the Brazilian and MERCOSUR Legislation and evaluation of the organic coatings of the body, bottom, end and side stripe, in relation to the internal lacquer weight, porosity, identification, adherence and curing degree. The storage test was conducted during a period of 6 months under two conditions of controlled temperature, 25°C ± 2°C and 35°C ± 3°C, with evaluations at intervals of 15 days during the first month, 30 days up to the second month and then every 60 days to complete 180 days of storage. The parameters included in the evaluations were visual internal appearance of the cans, vacuum level, oxygen, nitrogen, carbon dioxide and hydrogen composition of the cans headspace, sensorial analysis, instrumental evaluation of color, pH, total titratable acidity, soluble solids (°Brix), iron, tin and chromium concentration in the passion fruit juice and ascorbic acid content (vitamin C), which was only determined at zero day and after 15 and 180 days of storage. The results showed that all cans presented no restriction for use in contact with aqueous acid foodstuffs (pH < 5;0) at processing temperatures of up to 100ºC, followed by prolonged use at temperatures of up to 40ºC. The results for vacuum level, pH, acidity and soluble solids in the juice remarried stable at the two temperatures throughout storage. In the same period at both temperatures, there was a decrease in vitamin content and a slight darkening of the juice. The alterations observed in the visual internal evaluation and the increase in hydrogen concentration in the can headspace and iron and tin concentrations in the juice, demonstrated the beginning of internal can corrosion. The sensorial evaluation demonstrated a loss of quality of the juice packed in the three cans, mainly in the cans stored at 35°C, but all juices maintained acceptable quality up to the 180th day of storage. The storage test showed that the three kinds of cans presented good performance for the packaging of passion fruit juice and that the sample with powdered lacquer on the side stripe presented a worse performance than the other two systems studied, due to the smaller protection offered by the lacquer applied to the body. The study allowed for the conclusion that the three packages studied could be used in the packaging of passion fruit juice with a shelf life of up to 6 months Mestrado Mestre em Tecnologia de Alimentos

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Poletto, Patrícia. "Produção, recuperação e avaliação de pectinases de Aspergillus niger LB-02-SF obtidas em biorreator de tambor rotativo." reponame:Repositório Institucional da UCS, 2015. https://repositorio.ucs.br/handle/11338/951.

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No presente trabalho, a produção de pectinases por Aspergillus niger LB-02-SF em estado sólido foi estudada em biorreator de tambor rotativo em escala de bancada. Adicionalmente, a extração e a concentração do extrato enzimático foram avaliadas. Com o extrato concentrado por ultrafiltração, formulações com KCl e glicerol foram testadas quanto à conservação da atividade enzimática e à eficiência no tratamento de sucos de frutas. Com respeito à produção das pectinases em biorreator, os parâmetros de operação avaliados foram: a agitação, a temperatura do cultivo, o volume de ocupação (30, 50 e 70%) e o fluxo específico de ar (0,18, 0,36, 0,54, 0,72 e 0,90 LkgM – litros de ar por kg de meio por minuto). Ensaios sem e com agitação do biorreator (frequência de 1 rpm por 5 minutos, a cada 120 minutos) indicaram que, para o volume de ocupação de 30%, a agitação leva ao aumento do crescimento fúngico e à redução da produção de enzimas, enquanto que com 50% de ocupação, comportamento oposto foi observado. Com 70% de ocupação, não foi observada diferença significativa entre as atividades pectinolíticas obtidas com e sem agitação, sendo que, em ambos os casos, a produção foi prejudicada pela insuficiente aeração do meio. O intervalo entre os eventos de agitação foram avaliados para o volume de ocupação em 70%, não sendo observada diferença significativa na produção de pectinases nos intervalos de 120 minutos (condição padrão) e 90 minutos. Para um intervalo de 60 minutos, a atividade reduziu-se em aproximadamente 58%. Os cultivos com controle de temperatura em 34oC e sem controle indicaram que a produção enzimática foi favorecida com a elevação natural da temperatura do cultivo, um aspecto que pode estar relacionado a uma condição de estresse que levaria à maior produção enzimática. Fluxos específicos de ar entre 0,18 e 0,90 LkgM foram testados em ensaios com 30 e 50% de volume de ocupação do biorreator. Maior crescimento fúngico foi atingido quando o biorreator foi carregado com menor volume de ocupação. Com o fluxo intermediário de 0,54 LkgM, as maiores atividades enzimáticas para ambos os volumes de ocupação foram atingidas; porém, a ocupação de 50% do volume resultou na maior atividade pectinolítica, 178,2 U/g, com uma atividade de 133,4 U/g sendo medida com 30% de ocupação. No estudo sobre a extração de pectinases do meio sólido, com água pH 4, sob agitação de 200 rpm, foi observado que tempos entre 15 e 120 minutos apresentaram resultados similares. Os resultados atingidos apontam que para maior produção enzimática o biorreator deve ser operado com 50% de ocupação, fluxo específico de ar de 0,54 LkgM e intervalos entre as agitações de 120 minutos. Temperaturas de extração de 20, 30 e 40oC não influenciaram na extração de proteínas, porém a atividade de pectinases foi reduzida em 40% a 40oC, possivelmente em razão da termoestabilidade da enzima. Entre as razões de extração sólido / líquido avaliadas, o valor de 1/10 foi a que resultou na maior atividade enzimática solubilizada, sendo recuperados 81% da atividade pectinolítica presente no meio. Nos ensaios de concentração, a ultrafiltração do extrato concentrado sem qualquer tratamento prévio resultou em recuperação de 59% das enzimas e em fluxo final de permeado da ordem de 11 L/m2/h. Por outro lado, o protocolo de operação que incluía o uso de carvão ativado e microfiltração, apresentou recuperação de enzimas de 74% e fluxo final de permeado de 24 L/m2/h, demonstrando a importância dos pré-tratamentos na ultrafiltração. Previamente à preparação das formulações enzimáticas, um volume de 30 L de extrato bruto foi concentrado 103 vezes por ultrafiltração, com recuperação enzimática de 69%, e um extrato com 663 U/mL foi obtido. Este extrato concentrado foi formulado com 20, 30, 40 e 50% (m/m) de glicerol e 2% (m/m) de KCl e avaliado, por 59 semanas, quanto à conservação da atividade a 5°C. Ao final do período de teste, a amostra controle (sem aditivos) teve queda de 25% da atividade além de apresentar contaminação microbiana, enquanto as formulações mantiveram a atividade em torno de 100% durante todo o experimento. A formulação com 50% de glicerol foi utilizada na maceração de uva bordô e na despectinização de sucos de maçã, uva rosada e amora, demonstrando comportamento similar aos encontrados com as preparações comerciais Novozym 33095 e Pectinex Ultra SP-L utilizadas como referência. Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2015-06-12T13:40:01Z No. of bitstreams: 1 Tese Patricia Poletto.pdf: 3241164 bytes, checksum: 9357cad3cf87872921762739e3076144 (MD5) Made available in DSpace on 2015-06-12T13:40:01Z (GMT). No. of bitstreams: 1 Tese Patricia Poletto.pdf: 3241164 bytes, checksum: 9357cad3cf87872921762739e3076144 (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior. In the present work, the production of pectinases by Aspergillus niger LB-02-SF in solid-state cultivation was studied using a rotating drum bench bioreactor. Furthermore, extraction and concentration of enzymes by ultrafiltration were evaluated. Formulations with the concentrated extract, KCl and glycerol were assayed with respect to the maintenance of activity level and the efficiency in the treatment of fruit juices. With respect to the production of enzymes in bioreactor, the operational parameters evaluated were agitation, cultivation temperature, occupation volume (30, 50 and 70%) and specific air flow (0.18, 0.36, 0.54, 0.72 e 0.90 LkgM – liter of air per kilogram of medium per minute). Tests without and with agitation of the bioreactor (1 rpm per 5 minutes each 120 minutes) indicated that, with occupation volume of 30%, agitation leads to increasing fungal growth and decreasing enzyme production, whereas with 50% of occupation an opposite behavior was noticed. With 70% of occupation volume, no significant difference was observed among the pectinolytic activities achieved with and without agitation, the production being hindered in both cases by the insufficient aeration of medium. The interval between agitation events was evaluated for an occupation volume of 70% and no significant difference in enzyme production was observed for the intervals of 90 and 120 minutes (standard condition). For the interval of 60 minutes, the activity was reduced in approximately 58%. The cultivations with temperature control at 34oC and without control indicated that enzyme production was favored with the natural increase of medium temperature, an aspect that could be related to a stress condition that would lead to a higher enzyme production. Specific air flows between 0.18 and 0.90 LkgM were evaluated for 30 and 50% of bioreactor occupation volume. Larger fungal growth was observed when the bioreactor was loaded with the smallest occupation volume. With the intermediate flow of 0.54 LkgM, the highest enzyme activities were achieved for both occupation volumes; however, the occupation volume of 50% resulted the higher activity of 178.2 U/g, with an activity of 133.4 U/g being measured for 30% of occupation. The results achivied indicated that for a higher enzyme production, the bioreactor should be conducted with 50% of occupation volume, specific airflow of 0.54 LkgM and interval between the agitations of 120 minutes. In the study on the extraction of pectinases from the solid medium with water pH 4, under agitation, it was observed that extraction times from 15 to 120 minutes presented similar results. The extraction temperatures of 20, 30 and 40oC did not influence protein extraction, but pectinase activity was reduced in 40% at 40oC, possibly due to the low enzyme thermostability. Among the extraction ratios of solid/liquid assessed, the value 1/10 resulted in the highest enzyme activity solubilized, with recovery of 81% of the pectinolytic activity that was present in the medium. In the concentration tests, ultrafiltration of concentrated extract with no previous treatment resulted in 59% of enzyme activity recovery and in a final permeate flux of about 11 L/m²/h. On the other hand, the operation protocol that included the use of activated charcoal, microfiltration and ultrafiltration presented enzyme recovery of 74% and final permeate flux of 24 L/m2/h, results that demonstrate the importance of pre-treatments in this process. Previously to the preparation of enzyme formulations, a volume of 30 L of enzyme extract was 103-fold concentrated by ultrafiltration, with 69% of enzyme recovery, and a final 663-U/mL extract was obtained. This concentrated extract was formulated with 20, 30, 40 and 50% (w/w) of glycerol and 2% (w/w) of KCl and evaluated for 59 weeks with respect to the enzyme activity conservation at 5ºC. At the end of the test period, the blank sample (with no additives) presented an activity decrease of 25% and also microbial contamination, whereas the formulations preserved 100% of the initial activity along the experiment. The 50%-glycerol formulation was used for Bordô grape maceration and for depectinization of apple, Rosé grape and blackberry juices, showing statistically similar results to those obtained with the commercial preparations Novozym 33095 and Pectinex Ultra SP-L used as reference. The results attained in this work pointed out to the possibility of scaling-up this process, from the enzyme production in solid-state cultivation to the achievement of an enzyme formulation that has shown potential to be used in the industry of fruit juice.

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Hanychová, Silvie. "Validace metody HPLC pro stanovení organických kyselin v nápojích." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2018. http://www.nusl.cz/ntk/nusl-376853.

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This diploma thesis focuses on validation of RP–HPLC method for determination of organic acids in fruit juices. The aim of this thesis was to determine suitability of the method for verification of the fruit juices authenticity based on analysis of organic acids. The theoretical part describes chemical composition of fruit and fruit juices and focuses on organic acids. It provides description of various methods of organic acids analysis with more detailed description of High Performance Liquid Chromatography and its validation. The experimental part focuses on optimalization and validation of the method. Samples of malic, citric, succinic and ascorbic acid were analysed. The optimalized method was validated and following performance parameters were determined: repeatability, linearity, limit of detection (LOD) limit of quantitation (LOQ). RP–HPLC method was applied to real samples of 100% fruit juices (apple, orange and grapefruit) and the authenticity parameters were verified.

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