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1
Uddin, Jalal. "NMR based Metabolomics in Food Chemistry." Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424379.
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Metabolomics is defined as the systematic analysis of hundreds or thousands of small metabolites present in a living system. It has emerge as an important field of study along with other, already established ‘omics’ sciences, i.e., genomics, proteomics and transcriptomics. Metabolomics is well established in the field of medicine, drug toxicity and disease diagnosis. Among the existing analytical techniques, NMR is a fast, reproducible and non-destructive technique to construct an informative snapshot of the metabolites under certain conditions. NMR data give metabolic signature information of the samples when it is combined with data preprocessing and chemometric tools, such as multivariate statistical techniques. NMR-based metabolomics is still expanding in the field of the food chemistry. In this context, this Ph.D. thesis is focused on two major aspects, which show applications of NMR-based metabolomics in food chemistry.
1. Many nutraceutical products possess powerful antioxidant activity as demonstrated in many chemical in vitro tests and in several in vivo trials. Nevertheless, the mechanism of their activity is not completely studied in detail. Due to their poor bioavailability and fast metabolism, studies on the in vivo antioxidant effects are still needed. We performed longitudinal experiments on Sprague Dawley (SD) rats using two commonly available nutraceutical antioxidant products, namely, Curcumin (chapter 2) and Resveratrol (chapter 3). The effects of different doses of orally administered standardized antioxidant extracts in healthy rats were investigated by untargeted metabolomic analysis based on LC-MS and NMR spectrometry. The experiments were carried out over different periods of time for different antioxidants. Changes in the urinary metabolome were evaluated by monitoring the 24-hour urine composition by 1H-NMR and HPLC-MS. The two different approaches were able to detect variations in the urinary levels of antioxidant markers, leading to the observation of different metabolites thus proving the complementarity of these two analytical techniques for metabolomic purposes. Analytical tools such as MS and NMR spectroscopy in combination with chemometrics can profile the impact of time, stress, nutritional status, and environmental perturbations on hundreds of metabolites simultaneously. This results in complex, massive data sets that must be analyzed through a careful statistical protocol. Our strategy included data preprocessing, data analysis and validation of statistical models. After several data processing steps, principal component analysis (PCA) and partial least-squares (PLS) were used to identify urine biomarkers. The PLS models were validated by permutation tests and critically important variables were validated through univariate analysis.
2. The second part of this thesis (chapters 4 and 5) describe the use of NMR-based metabolomics as a fast, convenient, and effective tool for origin discrimination and biomarker discovery in food analysis. Traditionally, the determination of the floral origin of honey is made from palynological analysis. The method is based on the identification of pollen by microscopic inspection. However, melissopalynological analysis needs expertise and also it is not a very reliable technique for the discrimination of botanical origin of some types of honey. Also, honey regulation in the EU (Codex Alimentarius Commission 2001; European Commission 2002) emphasizes that the botanical and geographical origins of the product must be printed on the label in order to avoid the fraud such as adulteration with industrial sugar, selling product under false name or mixing the honey of different floral origin. Therefore, there is need to establish a method to discriminate honey from different origin. The aim of this work was to develop an NMR-based metabolomic approach that used multivariate statistical analysis to discriminate the botanical (chapter 4) and entomological (chapter 5) origin of different types of honey. Multivariate statistical analysis helped us to identify the most relevant signals to differentiate honey botanically and entomologically. The obtained data sets were useful in the search of markers responsible for the discrimination of different honey samples from different botanical species and produced by different bee species.La metabolomica è definita come l'analisi sistematica di centinaia o migliaia di piccoli metaboliti presenti in un sistema vivente. È emerso come un importante campo di studio insieme ad altre, già affermate scienze "omiche", vale a dire, genomica, proteomica e trascrittomica. La metabolomica è ben consolidata nel campo della medicina, nello studio della tossicità di farmaci e nella diagnostica. Tra le tecniche analitiche esistenti, NMR è veloce, riproducibile e non distruttiva, utile per fornire una fotografia informativa sui metaboliti in determinate condizioni. Dati NMR forniscono informazioni metaboliche che caratterizzano i campioni quando combinati con una pre-elaborazione dei dati e con strumenti chemiometrici, come le tecniche di statistica multivariata. La metabolomica basata sull’NMR è ancora in espansione nel campo della chimica degli alimenti. In questo contesto, questa tesi di Dottorato si concentra su due aspetti principali, che mostrano applicazioni della metabolomica basata sull’NMR in chimica degli alimenti. 1. Molti prodotti nutraceutici possiedono potente attività antiossidante, come dimostrato in molti test chimici in vitro e in diverse prove in vivo. Tuttavia, il meccanismo della loro attività non è completamente studiato in dettaglio. A causa della loro scarsa biodisponibilità e metabolismo veloce, sono ancora necessari studi in vivo sugli effetti antiossidanti. Abbiamo condotto esperimenti longitudinali su ratti Sprague Dawley (SD) utilizzando due prodotti antiossidanti nutraceutici comunemente disponibili, vale a dire, curcumina (capitolo 2) e resveratrolo (capitolo 3). Gli effetti di diverse dosi di estratti antiossidanti standardizzati somministrati per via orale nei ratti sani sono stati studiati mediante analisi metabolomica non mirata (untargeted) basata su LC-MS e spettrometria NMR. Gli esperimenti sono stati eseguiti lungo diversi periodi di tempo per diversi antiossidanti. Le variazioni del metaboloma urinario sono state valutate attraverso il monitoraggio della composizione delle urine di 24 ore usando 1H-NMR e HPLC-MS. I due differenti approcci sono stati in grado di rilevare le variazioni dei livelli urinari di marcatori antiossidanti, portando all’osservazione di diversi metaboliti e dimostrando così la complementarità di queste due tecniche analitiche per scopi metabolomici. Strumenti di analisi come la spettroscopia NMR e MS in combinazione con chemiometria possono delineare l'impatto del tempo, dello stress, dello stato nutrizionale, e di perturbazioni ambientali su centinaia di metaboliti contemporaneamente. Ciò comporta complessi enormi set di dati che devono essere analizzati mediante un protocollo statistico accurato. La nostra strategia ha compreso una pre-elaborazione dei dati, l’analisi dei dati e la validazione dei modelli statistici. Dopo varie fasi di elaborazione di dati, l’analisi delle componenti principali (PCA) e l’analisi dei minimi quadrati parziali (PLS) sono state utilizzate per identificare i biomarcatori urinari. I modelli PLS sono stati convalidati dai test di permutazione e le variabili di importanza critica sono stati convalidati attraverso analisi univariata. 2. La seconda parte di questa tesi (capitoli 4 e 5) descrivono l'uso di metabolomica basata su NMR come strumento veloce, conveniente ed efficace per la discriminazione di origine e la scoperta di biomarcatori in analisi degli alimenti. Tradizionalmente, la determinazione dell'origine floreale del miele è condotta mediante analisi palinologica. Il metodo si basa sulla individuazione di polline mediante ispezione microscopica. Tuttavia, l'analisi melissopalinologica richiede perizia ed inoltre non è una tecnica molto affidabile per la discriminazione di origine botanica di alcuni titpi di miele. Inoltre, la regolamentazione del miele nell'Unione Europea (Codex Alimentarius 2001; Commissione Europea 2002) sottolinea che le origini botaniche e geografiche del prodotto devono essere stampate sull'etichetta, per evitare frodi, come l'adulterazione con zucchero industriale, vendita di prodotti sotto falso nome o aggiunte di miele di diversa origine floreale. Pertanto, vi è la necessità di stabilire un metodo per distinguere miele di diverse origini. Lo scopo di questo lavoro è stato quello di sviluppare un approccio metabolomico basato sull’NMR che ha utilizzato l'analisi statistica multivariata per discriminare l'origine botanica (capitolo 4) ed entomologica (capitolo 5) di diversi tipi di miele. statistica multivariata ci ha aiutato ad identificare i segnali più importanti per differenziare il miele sia dal punto di vista botanico che entomologico. I set di dati ottenuti sono stati utili nella ricerca di marcatori responsabili della discriminazione dei diversi campioni di miele di diverse specie botaniche e prodotti da diverse specie di api.
2
Keramat, Javad. "The chemistry of the coloured compounds formed during sugar manufacture." Thesis, University of Reading, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241642.
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Allmann, Michael. "Applications of the polymerase chain reaction (PCR) in food chemistry /." [S.l.] : [s.n.], 1994. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Hoogland, J. S. "Properties of low molecular weight food surfactants." Thesis, University of Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333908.
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Matteo, Roberto <1985>. "Non-food Brassicas for green chemistry purposes through a biorefinery approach." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/8006/1/Matteo_Roberto_tesi.pdf.
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The valorization of Brassica oilseed crops, starting from the agronomical phase up to the exploitation of the derived products, was studied.
Camelina sativa (L.) Crantz applications in biorefineries is of deep interest, given the high added value of its oil and oilseed cake residue. Camelina was evaluated as a case study for the cultivation in the Po valley. In such conditions, camelina has shown to be potentially well adaptable and had a positive impact on the yields of the subsequent crop. Thus, studies on camelina management and its impact on soil properties deserve more attention.
Novel Brassica defatted seed meals (DSMs), containing different glucosinolates, were applied in the control of the southern root-knot nematode, Meloidogyne incognita (Kofoid & White Chitwood) in controlled glasshouse conditions. Among different Brassica DSMs, the best results in the reduction of M. incognita infestation were achieved by Eruca sativa, Barbarea verna and Brassica nigra DSMs. These first results open new perspectives for innovative bioactive molecules for biofumigation applied in cropping systems where nematode suppression is critical.
Finally, the effect of Brassica DSMs, applied in formulations with and without crude glycerin, on seed germination inhibition was evaluated. The most effective formulations were applied in in vitro and glasshouse trials to evaluate the germination inhibition of black-grass (Alopecurus myosuriodes Huds.). Both in vitro and in vivo experiments confirmed the effectiveness of Brassica DSMs formulated with glycerin, especially B. nigra, in germination inhibition. Among different advantages, the proposed formulations for weed control are completely bio-based, organic farming friendly, present a good fertilizing properties and a combined effect both on weeds and on soil borne pests and diseases.
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Custodio, Joseph M. "Predicting intestinal transporter effects in food-drug interactions and the role of food on drug absorption." Diss., Search in ProQuest Dissertations & Theses. UC Only, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3324590.
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Chong, Miguel. "T. P. COULTATE. Food: the chemistry of its components. [London] : The Royal Society of Chemistry, 1996. 360 p." Revista de Química, 2013. http://repositorio.pucp.edu.pe/index/handle/123456789/100294.
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Pironti, Concetta. "Innovative applications of stable carbon isotope ratio in environmental and food chemistry." Doctoral thesis, Universita degli studi di Salerno, 2018. http://hdl.handle.net/10556/3022.
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2016 - 2017In the last year, the stable isotope ratio analysis has become a useful tool with many applications in different scientific area. In particular the characteristic isotope signature of materials has permitted to identify authenticity and traceability of food sample and isotope composition has become a valuable marker in environmental studies. This work shows the applicability of analytical methods for isotopic carbon determination in food and environmental samples and the innovative use of δ13C in cultural heritage as valuable tool to trace pollutant fate. The first part is dedicated to the improvement of spectroscopic methods as Fourier Transform Infrared (FT-IR) and Non-Dispersive Infrared spectroscopy (NDIRS) and their application to identify geographical origin in sample like pasta, cocoa, olive oil. The results conducted in order to assess the robustness of the two alternative methods respecting IRMS showed a strong correlation like a demonstration of the positive relationship between the tested analytical methods. A new method was developed 13C NMR spectroscopy to determine the bulk 13C/12C carbon isotope ratio of inorganic carbonates and bicarbonates at natural abundance. In literature the use of 13C NMR spectroscopy was focused on 13C position-specific isotope analysis of organic molecules; in this work it was reported the improvement of NMR methodology able to obtain stable carbon isotope ratio in bulk material using an internal standard...[edited by Author]
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Gray, Jason. "Monoglyceride food surfactants and their interaction with whey proteins." Thesis, University of Salford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301418.
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Chityala, Pavan Kumar. "Evaluation of Xanthan/Enzymatically Modified Guar Gum Mixtures in Oil-in-Water Emulsions." TopSCHOLAR®, 2015. http://digitalcommons.wku.edu/theses/1528.
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Oil-in-water emulsions have wide range of applications in food industry because of their structure-forming properties, and as delivery systems of polyunsaturated fatty acids into foods. The thermodynamic instability of oil and water, and high susceptibility of unsaturated fatty acids to oxidation lead to physical and oxidative stability in oil-in-water emulsions. These instability processes are generally controlled by incorporating proteins and polysaccharides into oil-in-water emulsions. The objective of this study was to evaluate xanthan/enzymatically modified guar (XG/EMG) polysaccharides on the physical and oxidative stability of 2 wt% whey protein stabilized oil-in-water emulsions containing 20% v/v menhaden fish oil. Enzymatic modified guar gum was obtained by hydrolyzing native guar gum using α-galactosidase enzyme. Emulsions were prepared for guar gum (GG), xanthan gum (XG), xanthan/guar (XG/GG), and xanthan/enzymemodified guar (XG/EMG) gum mixtures using 0, 0.05, 0.1, 0.15, 0.2, and 0.3% gum concentrations. Emulsions were then evaluated for creaming, viscosity, particle size, and microstructure to evaluate the physical stability, and peroxide value, TBARS value and GC-MS solid phase micro extraction (SPME) experiments were performed to evaluate the oxidative stability. Emulsions containing XG/EMG gum mixtures exhibited better creaming stability and higher viscosity of all the emulsion types. However, XG/EMG gum concentrations did not affect the droplet size of the emulsions. The microstructures revealed decreased flocculation in emulsions with XG/EMG mixtures. The primary and secondary lipid oxidation measurements indicated that emulsions containing XG/EMG gum mixtures were more effective in preventing the lipid oxidation of all the emulsion types. From the results, it is evident that XG/EMG gum mixtures can be used as emulsifiers in oil-in-water emulsions to increase both physical and oxidative stability.
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Agater, Irena Barbara. "Applications of permanganate chemiluminescence to the analysis of food components." Thesis, University of Huddersfield, 1999. http://eprints.hud.ac.uk/id/eprint/5955/.
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Chemiluminescent oxidations with manganese reagents have been investigated using flow and spectroscopic techniques. An assay has been developed for ascorbic acid using the chemiluminescent oxidation of ascorbic acid with permanganate in acid medium. The assay has a linear range of 5xl 0-7 to 1 X, 0-3 mol dM-3 and has been applied to a range of food supplements and fruit juices. The addition of a manganese (11) catalyst extends the applicability of acid permanganate to the determination of sugars and polyhydric alcohols. The reaction has been optimised for the determination of mono and disaccharides in a flow injection system. Development of a reagent based on manganese (111)i,n a methanol and sulphuric acid solution, has further extended the scope of the reaction enabling the determination of fructose in the range 1 X1 0-7 to 1 X1 0-3 mol d M-3. The reagent has successfully been used in post column detection with HPLC. It has been established that the light emission occurs after manganese (VII) has been reduced and appears to be connected with the production and disappearance of Mn (111). Chemiluminescence spectroscopy has shown that the spectra are the same for a large number of aliphatic and aromatic polyhydroxy compounds. The spectrum remains the same whether the oxidising reagent is Mn (VII), Mn (IV) or Mn (111)i,n dicating that the same emitting species is involved in all these reactions and that it involves Mn(III) and/or Mn(II).
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Kong, Emily S. "EFFECT OF pH AND TEMPERATURE ON THE BINDING INTERACTIONS OF CAFFEINE AND CHLOROGENIC ACID WITH SODIUM CASEINATE." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/947.
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Coffee is a popular and well-loved beverage consumed worldwide by millions of people every day. While most patrons of coffee do so because of its unique and satisfying taste, consumers may be unaware of the potential beneficial health effects it also imparts. The antioxidants found in green coffee beans collectively known as chlorogenic acids (CGA) and caffeine are two of the most abundant bioactive compounds present in coffee. Both these bioactive compounds have been implicated in many studies to impart a wide range of health benefits, from reducing the risk of Type 2 diabetes, to their use as aides in weight management. Indeed, epidemiological studies on people who consume moderate amounts of coffee on a regular basis have unanimously shown benefits to overall health.
While caffeine and CGA are naturally occurring compounds in coffee, their potential in conferring beneficial health effects warrant research into other potential food matrixes that can be used to bind and deliver these bioactive compounds into foods that do not naturally contain them. Milk proteins, specifically caseins, have been shown to be excellent vehicles to both bind and deliver sensitive bioactive compounds of various chemical and physical properties. Caseins have been shown in numerous studies to successfully bind to molecules such as vitamin D2, ω-3 polyunsaturated fatty acids (DHA), and iron to name a few. Because caseins exhibit high versatility in binding a variety of molecules, caseins were the milk protein of choice for the experiments in this thesis.
Polyphenols have been the subject of many studies on its binding capacity with milk proteins, but research on the binding capacity of caffeine with caseins is limited. Therefore, the objectives of this thesis are threefold: 1) develop, optimize and validate an HPLC method for the accurate and simultaneous determination of caffeine and CGA, 2) establish a procedure by which caffeine and CGA bind to sodium caseinate, and 3) determine the optimal treatment conditions of pH and temperature to increase binding interactions and speculate on the mechanism of binding for each bioactive compound.
A reversed phase HPLC (RP-HPLC) method was developed and subjected to validation studies with good results in linearity (caffeine R2 = 0.9992, CGA R2 = 0.9995) and precision (RSD of caffeine <1%, RSD of CGA <2%). The developed method also demonstrated selectivity for caffeine and CGA. This method was then used to analyze sodium caseinate samples containing caffeine and 5-CGA. The results from these studies have shown that binding interactions between caffeine and sodium caseinate are temperature dependent (p < 0.01) whereas binding interactions between CGA and sodium caseinate are influenced by both pH and temperature (p < 0.01). Elucidating the binding mechanisms of caffeine and CGA to sodium caseinate and providing a sensitive analytical technique by which these compounds can be accurately quantified may facilitate future research involving the use of caffeine and CGA in many other facets, as well as promoting its increased use in the dairy industry.
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Channell, Guy Andrew. "Oxidative flavour chemistry and biochemistry in parsley." Thesis, University of Nottingham, 1996. http://eprints.nottingham.ac.uk/13970/.
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Deterioration of flavour quality during processing and storage is often brought about by oxidative processes. These typically involve oxygen or an active form of oxygen in effecting transformation of a wide range of volatile and non-volatile compounds, including key quality chemicals, flavour precursors and antioxidants. To investigate the nature of the chemical and biochemical change within vegetables and herbs, unblanched frozen parsley was selected as a suitable tissue. The chemical status of parsley during technological processing was determined using novel analytical protocols (SNCV A/SNCNV A) implemented as part of a unified strategy for the quantitative analysis of volatile and non-volatile species. The analysis utilized a single stabilized solution produced from plant tissue, under a regime which minimized isolation stress and artifact formation. On frozen storage (-10OC) the principal volatiles of parsley, myrcene, beta-phellandrene and menthatriene were extensively degraded to non-volatile products at differential rates. p-Cymenene and the tentatively assigned menthatriene diepoxide were formed as minor volatile oxidation products. Myristicin remained largely unchanged. Under similar frozen storage, chlorophyll 'a' displayed significant degradation with only minor amounts of chlorophyllide 'a', pheophytin 'a' and 13[superscript]2 hydroxychlorophyll 'a' formed. Ascorbic acid was extensively degraded in timescales preceding monoterpene and chlorophyll loss. Thermal blanching of parsley extensively prevented the degradation of the monoterpenes, suggesting that endogenous enzymes were responsible for the changes. Elimination of oxygen, in the absence of blanching, prevented volatile loss, confirming the requirement for oxygen. The hypothesis that peroxidase can operate in a co oxidative couple with the flavonoid, apigenin-7-glucoside and hydrogen peroxide, as proposed by Yamauchi (1985), was investigated to establish its potential role in the degradation of terpenoids and chlorophyll. In model experiments, using horseradish peroxidase, menthatriene and chlorophyll showed extensive degradation only when all components of the couple were present. In addition the requirement for oxygen was also established. Naringenin and umbelliferone have been shown to behave similarly to apigenin, as co-substrates for peroxidase. Lycopene, with some structural similarity to menthatriene, was also susceptible to co-oxidation. Polyphenol oxidase, proposed to operate in a similar fashion to peroxidase with mono- and di-phenols as substrates (Montedoro et al. 1995), in model experiments did not cause the degradation of chlorophyll. The co-oxidative role of lipoxygenase in parsley is believed to be of minor significance, however, it is likely to be responsible for the production of low levels of hexanal observed during thawing of frozen parsley. From this thesis it is concluded that the aroma and colour quality loss in frozen unblanched parsley probably results from the oxidative degradation of the unsaturated monoterpenes and chlorophyll 'a' respectively via an oxidative cascade initiated by the action of peroxidase.
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Perez, Locas Carolina. "Mechanism of formation of thermally generated potential toxicants in food-related model systems." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21907.
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The detailed mechanism of formation of selected Maillard-induced toxicants generated in model systems containing 13C- and 15N-labeled precursors, were investigated using isotope labeling and Py-GC/MS based techniques. Investigation of different sources of acrylamide (AA) formation in model systems have indicated the presence of two pathways of acrylamide generation; the main pathway specifically involves asparagine to directly produce acrylamide after a sugar-assisted decarboxylation step that passes through a 5-oxazolidinone intermediate and the second, non-specific pathway involves the initial formation of acrylic acid from different sources and its subsequent interaction with ammonia and/or amines to produce acrylamide or its N-alkylated derivatives. Furthermore, to identify the relative importance of AA precursors, the decarboxylated Amadori product (AP ARP) and the corresponding Schiff base were synthesized and their relative abilities to generate AA under dry and wet heating conditions were studied. Under both conditions, the Schiff base had the highest intrinsic ability to be converted into AA. To gain further insight into the decarboxylation step, the amino acid/sugar reactions were also analyzed by FTIR to monitor the formation of the 5-oxazolidinone intermediate known to exhibit a peak in the range of 1770-1810 cm-1. Spectroscopic studies clearly indicated the formation of an intense peak in the indicated range. Similar to acrylamide, mechanism of furan formation was also studied using 13C-labeled sugars and amino acids. These studies have indicated that furan can be formed through aldol condensation of acetaldehyde and glycolaldehyde and these precursors can be formed from certain amino acids, monosaccharides and ascorbic acid. Moreover, using specifically 13C-labeled sucrose at C-1 of the fructose moiety, hydroxymethylfurfural (HMF) formation was studied at different temperatures. Under dry pyrolytic conditions and at temperatures above 250oC, 90% oLe mécanisme détaillé de formation de certaines composantes toxiques générées par des précurseurs contenant des isotopes 13C et 15N, fut étudié en utilisant des techniques basées sur les principes d'incorporation d'isotopes lourds avec la pyrolyse couplée à la CG/SM (Py-CG/SM). L'investigation de différentes sources d'acrylamide a indiqué la présence de deux routes de formation; la route principale implique spécifiquement l'asparagine qui produit l'acrylamide directement suite à une décarboxylation par l'entremise des sucres passant par un intermédiaire 5-oxazolidinone, tandis qu'une seconde route non-spécifique implique une formation initiale d'acide acrylique de différentes sources suivie d'une interaction avec une molécule d'ammoniac et/ou d'amines afin de produire l'acrylamide ou ses dérivés. De plus, afin d'identifier l'importance relative des précurseurs de l'acrylamide, le produit Amadori décarboxylé (AP ARP) ainsi que la base Schiff correspondante furent synthétisés et leur habilité relative à générer l'acrylamide après un traitement thermique en milieu sec et aqueux fut étudié. Dans les deux cas, la base Schiff a démontré une habilité de conversion en acrylamide plus importante. Afin d'obtenir un aperçu approfondi de l'étape de décarboxylation, les réactions entre les sucres et les acides aminés furent aussi analysées par l'IR-TF surveillant ainsi la formation de l'oxazolidinone, une composante intermédiaire reconnue par la présence d'un pic entre 1770-1810 cm-1. Les études spectroscopiques démontrent clairement la formation d'un pic intense dans cet écart. Similaire à l'acrylamide, les mécanismes de formation du furane furent aussi étudiés par l'entremise des sucres et acides aminés contenant des isotopes lourds. Ces études ont indiqué que le furane peut être formé par une condensation aldol de l'acétaldéhyde et le glycoaldéhyde et ses précurseurs, par certains acides aminés, des monosacch
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Darag, Omima Ali. "Influence of Storage Duration, Temperature, and Oxygen on Quality of Stored Dehydrated Foods." DigitalCommons@USU, 2003. https://digitalcommons.usu.edu/etd/5494.
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This study was undertaken to determine the effect of oxygen absorber packets (OAP) (AGELESS Z.300 E) in improving the shelf-life of selected dried food products, including dried potato pearls, dried sliced apple, dried carrot, white rice, nonfat dry milk, all purpose flour, rolled oats, and wheat. Items were stored at four different temperatures (-20, 10, 21, and 29.5°C) over a period of 24 months with observations at 6-month intervals. Hunter colorimeter, thiobarbituric acid reactive substance (TBARS) germination rate, gluten weight, and volume were parameters used as quality indicators of various dried foods.
Statistical analysis indicated a significant time and temperature effect for almost all the stored products. Storage at a high temperature (29.5°C) renders OAP ineffective in reducing browning during storage. Potato pearls, dried sliced apple, and dried carrot exhibit darkening by the first 6 months of storage at 29.5°C regardless of oxygen status of the container. White rice showed yellowing under the same conditions. Most of the dried food products that were stored at 10 and 21°C with or without oxygen absorber packets maintained their color as indicted by a relatively constant lightness reading (L*) over time. TBARS values rose in all stored food with increasing storage time, especially when the dried products were stored at higher temperature (29.5°C). Statistical analysis indicated a significant OAP effect in reducing TBARS concentration over time.
Germination of wheat kernel was reduced to less than 80% after 24 months of storage at 29.5°C. However, when stored with oxygen absorber packets, germination was still 86%. Storage length and temperature are the primary factors that determine the quality of home-stored dried food items.
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Challou, Floritsa. "Surface pasteurisation of food packages by the inversion method." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6701/.
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Thermal processing is the most widely used and well established preservation method used in the food industry for ensuring food safety and extending the shelf life of food products. Besides from the food product, the package needs also to be decontaminated to achieve the required safety goals. This research is concerned with surface pasteurisation treatments in food packages by the method of inversion, primarily for hot-filled food products. Starch solutions and tomato soup, used as model fluids in the current work, were hot-filled in glass jars, were sealed and then inverted for thirty seconds at a filling temperature of 80oC for achieving a target process equivalent of 5 min at 70oC; the inversion step was used as a thermal treatment of the headspace and the lid. The inverted jars showed significantly higher process values for the headspace and the lid with the filling temperature being the most important parameter. The effectiveness of the inversion step during hot-fill treatments was quantified by the use of two monitoring techniques, the traditional temperature sensors and the alternative, enzymic based (Bacillus amyloliquefaciens α-amylase) Time Temperature Integrators (TTIs). TTIs are small devices with kinetics similar to the microorganisms, whose level of degradation is measured at the end of the thermal process. The enzyme activity obtained is integrated and the temperature history can be quantified. TTIs were tested for their reliability and accuracy under isothermal and non-isothermal conditions, and were then used for validating the hot-fill process.
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Maurer, Natalie. "Profiling Lipids for Authentication of High Value Ingredients by Mid-Infrared Spectroscopy Combined with Multivariate Analysis." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1329855553.
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Sigurdson, Gregory T. "Evaluating the Effects of Anthocyanin Structure and the Role of Metal Ions on the Blue Color Evolution of Anthocyanins in Varied pH Environments." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461253897.
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Scotter, Michael Joseph. "Aspects of the chemistry and analysis of the food colouring materials annatto and curcumin." Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327600.
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Crowson, Andrew. "The effects of electron beam irradiation on additives present in food-contact polymers." Thesis, Sheffield Hallam University, 1991. http://shura.shu.ac.uk/19520/.
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A range of additives (Irganox 1010, Irganox 1076, Irganox 1330, Irgafos 168 and Tinuvin 622) has been incorporated into a variety of food-contact polymers including polypropylene and low density polyethylene. Samples of these stabilized polymers were subjected to electron-beam or gamma irradiation to receive doses of 1,5,10,25 and 50 kGy. The effects of electron-beam irradiation on the amount of extractable antioxidant in polymers were determined. Using hplc techniques it was found that there was a dose-related reduction in the amount of extractable antioxidant similar to that caused by gamma irradiation. The magnitude of this reduction was found to be dependent upon the nature of both the antioxidant and the polymer type. Electron-beam irradiation was also found to cause a dose-related reduction in the levels of the antioxidants Irganox 1010 and Irganox 1076 migrating from polymers into a food simulant. This effect was similar to that caused by gamma irradiation. The extent of polymer binding of antioxidant fragments derived from Irganox 1076 following electron-beam irradiation was determined, using a radiochemical method. The amount of binding was found to be dose-related and of a similar order of magnitude to that caused by gamma-irradiation. This study has revealed the presence of many irradiation derived antioxidant transformation products in extracts from irradiated polymers. Attempts have been made to isolate and identify these compounds, and a number of possible structures are proposed following lc-ms studies. In some cases, the irradiation-derived transformation products appear to be different to those produced on thermally aging stabilized polymers. Irradiation was also found to give transformation products farmed via the cleavage of tertiary butyl groups from the parent molecules, and such compounds are not produced during the thermal aging of similar stabilized polymers, nor in model reactions between the antioxidants and t-butylperoxyl radicals. A brief examination of the effects of gamma irradiation on Tinuvin 622 in polypropylene was also carried out, and a number of UV absorbing transformation products were detected.
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Dunn, Jennifer. "The effect of spices on carboxymethyllyinse levels in biscuits." Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/15062.
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Master of ScienceFood Science Institute
J. Scott Smith
Carboxymethyllysine (CML) and other advanced glycation end products (AGEs) have been shown to affect diseases such as diabetes, cancer, and Alzheimer’s by inducing oxidative stress, inflammation, and tissue damage. CML is formed in foods through Maillard browning reactions and through various mechanisms that are affected by time, temperature, pH, water activity, trace metals, and antioxidants. Natural antioxidants can be found in plant and fruit extracts, as well as in spices. The research contained herein is in two parts. The first part includes preliminary work, which examines the percent recovery of CML from various solid phase extraction columns, the analysis of CML in maple syrup, barbeque sauce, honey, and infant formula. The data show that solid phase extraction with a C-18 cartridge produced the highest percent recovery when using a CML standard at 100 ppb, with a recovery of 69%. Furthermore, the analysis of the syrups and sauces is inconclusive, due to the very low levels of CML detected in the infant formula, and the complications due to the high levels of reducing sugars. The second part of the research examines the effect that cinnamon, onion, garlic, black pepper, and rosemary have on CML levels in biscuits. The data show that all of the spices inhibit the formation of CML, at each of the 0.5%, 1%, and 2% levels used in the experiment, by a minimum of 3% in 2% onion samples and a maximum of 79% in 0.5% cinnamon samples when looking at the cumulative data. When looking subsets of the data, the CML inhibition was a minimum of 59% in 2% onion samples and a maximum of 74% in 0.5% cinnamon samples. Other trends can be observed in the chroma values in the CML color data, which suggest that chroma values decrease as the spice level increases, but these are not statistically significant. They may be due to color from the spices themselves, or to the chemical changes in the Maillard reaction.
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Brekke, Sarah. "Trans-free fats and oils: chemistry and consumer acceptance." Kansas State University, 2013. http://hdl.handle.net/2097/16268.
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Master of ScienceDepartment of Food Science
Delores Chambers
Research has shown that trans fat consumption increases the levels of low-density lipoprotein (LDL) and has a direct correlation to the incidence of heart disease. It is now widely believed that trans fat intake adversely affects the health of consumers. A Food and Drug Administration (FDA) ruling, effective January 1, 2006, required declaration of trans fat content on all Nutrition Facts labels of food products. Around the same time local governments, such as the city of New York, and some restaurants followed suit by eliminating trans fats from their menus. The food industry’s initial concern with trans fat elimination/reduction was the loss of some functionality such as shelf life, stability, and creaming ability with trans-free fats and oils. Researchers are working to develop new trans-free fats and oils that do not have negative sensory properties and maintain the functionality of traditionally hydrogenated oils when used in baked and fried goods. This is an overview of the chemistry, health risks, and research that has been performed to either reduce or eliminate trans fats in food products.
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Grigor, John M. V. "Solute-solvent interactions as interpreted by nuclear magnetic resonance spectrometry : a contribution to taste science." Thesis, University of Reading, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259333.
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Friedli, Georges-Louis. "Interaction of deamidated soluble wheat protein (SWP) With other food proteins and metals." Thesis, University of Surrey, 1996. http://epubs.surrey.ac.uk/2204/.
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Vikström, Anna. "Improved basis for cancer risk assessment of acrylamide from food : Determination of glycidamide in vivo doses." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-37757.
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Acrylamide is formed in heat processing of many common foods. According to animal cancer tests acrylamide is a carcinogen. To estimate the cancer risk from exposure via food, the response at high doses in the cancer tests with rats has to be extrapolated to the exposure levels in humans. Acrylamide is biotransformed to the epoxide glycidamide, which is assumed to be the cancer-risk increasing agent. Therefore in vivo doses of both acrylamide and glycidamide should be measured in rats and humans and related to the acrylamide intake. In vivo doses (area under the time-concentration curve, AUC) of reactive compounds can be determined from measured reaction products, adducts, to hemoglobin (Hb). A study in mice showed that the food matrix does not have an influence on the absorbed amount of acrylamide from food. There was a linear dose-response of Hb-adduct levels from acrylamide and glycidamide. For cancer risk assessment it is important to describe variations between individuals in intake and in AUC. Hb-adduct levels of acrylamide and glycidamide were studied in two large groups. In non-smokers the acrylamide and glycidamide-adduct levels varied with a factor of 5 and 8, respectively. The influence of other compounds in the diet on metabolic formation/elimination of glycidamide was demonstrated by associations between the ratio of glycidamide-to-acrylamide-adduct levels and alcohol intake. Furthermore, a non-linearity between glycidamide and acrylamide-adduct levels was shown at low exposure levels. AUCs from acrylamide and glycidamide in rats exposed as in the cancer tests were measured and compared with AUCs in humans exposed to acrylamide through food. The AUC of glycidamide per given dose of acrylamide was somewhat higher in humans than in the rats. Altogether the generated data could be used to improve the cancer risk estimate of acrylamide in food. The obtained data strengthen earlier preliminary cancer risk estimates of acrylamide.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript. Paper 5: Manuscript.
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Campbell, Andrew Lee. "Fabrication of novel functional anisotropic micro-particles for foam stabilisation and structuring in food formulations." Thesis, University of Hull, 2009. http://hydra.hull.ac.uk/resources/hull:2488.
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This thesis is concerned with the fabrication of novel food-grade anisotropic solid particles for foam stabilisation and applications in food formulations. Two main techniques were employed for the fabrication of these particles. Acidic hydrolysis of Nata de Coco bacterial cellulose was used to form cellulose nano-rods which were applied as a foam scaffolding material. Characterisation and modification of Nata de Coco nano-rods was also carried out. It was found that cellulose nano-rods modified with a surface layer of ethyl cellulose exhibited good foamability.Secondly, a combination of in-shear-flow dispersion and solvent attrition techniques were employed to form micro-rods from the edible polymeric materials shellac, ethyl cellulose and zein. Characterisation of the properties of shellac, ethyl cellulose and zein micro-rods was carried out, together with assessments of their foam stabilisation ability. Stable aqueous foams were produced using shellac, ethyl cellulose and zein micro-rods as stabilisers, and ethyl cellulose micro-rods were also used to form water-in-oil emulsions.An extension of this technique was used in the fabrication of novel functional anisotropic food-grade micro-rods with micro-particle inclusions giving altered morphology. Enhanced foamability and drainage retardation was achieved using lumpy yeast-shellac micro-rods to stabilise aqueous foams. The method was extended to the production of aqueous dispersions of ballooned micro-rods, formed by two different protocols.This procedure also allowed the formation of novel, dual-function micro-rod capsules or ‘micro-ampules’ for stabilisation and encapsulation by inclusion of oils into the dispersed phase prior to micro-rod fabrication. The oils became trapped within the micro-rods resulting in micro-ampules with a range of morphologies which were characterised by fluorescence doping and microscopy.
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Walker, Michael John. "Safeguarding food : advances in forensic measurement science and the regulation of allergens, additives and authenticity." Thesis, Kingston University, 2016. http://eprints.kingston.ac.uk/37907/.
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This commentary reports on work published between 2005 and 2015 forming a record of a varied career building technical competence alongside strategic skills in the analytical chemistry and molecular biology of food. The unifying theme is practice based problem solving in the scientific regulation and enforcement of food safety and authenticity. The work demonstrates advances in sound, forensically robust, measurement science addressing problems arising from food additives, food authenticity and food allergens. In particular the mature discipline that underpins the regulation and enforcement of food additives is shown to be needed for the management of food allergens. The background to food regulation and enforcement is described alongside technical appeals in the official food control system to develop societally meaningful food surveillance, supported by a sustainable UK based official food control infrastructure (Public Analyst service) at the interface between science and the law. For food additives, publication of previously un-collated results informs regulatory practice and demonstrates the value of scientific collaboration between both jurisdictions on the island of Ireland. A definitive strategy is reported for the chemical analysis and risk assessment of ‘jelly mini-cups’ in which gel forming additives have caused choking fatalities and solutions to problems in the analysis of two illegal toxic additives, morpholine and dimethyl yellow are described. For food allergens the portfolio includes the first study to assess in quantitative terms the level of risk to peanut allergic consumers in take-away catering, leading to better training and similar work on coeliac disease and the availability of ‘gluten-free’ food. Systematic assessment of food allergen analysis and a programme of analytical improvement to support allergen risk assessment and risk management are discussed. A narrative account of an allergen related food sabotage incident and the subsequent Crown Court case and previously uncollated reports of court-sanctions for allergen noncompliances, severe incidents and deaths make key policy and practice recommendations for improvement in these areas. Page 7 of 162 In the study of food authenticity a critical review describes the nitrogen content of important species in the food supply chain as a proxy in the quantitative estimation of high value flesh foods in compound products. An exemplar study follows determining previously unavailable nitrogen factor data for farmed salmon and salmon frame mince. A critical survey of the up skilling of the UK Official Food Control System in DNA food authenticity techniques and major historical and contemporary reviews of food fraud (butter and horsemeat) support substantial policy and analytical recommendations. Many threats to our food supply can be assessed and managed only with the assistance of measurement science. Integrating elements of chemico-legal practice including lessons learned from ‘referee analyses’ and metrology in chemistry this commentary concludes with a synthesis describing major changes in the UK scientific food control system stemming from the author’s involvement in the ‘Elliott Review’ and recommendations for an international programme of work on food allergen analysis with interconnected learning for the benefit of the analytical and regulatory communities and society at large.
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Lengstrand, Anna. "Molecular Characterizing of Starch and Starch Based Materials in Food Packaging." Thesis, University of Kalmar, School of Pure and Applied Natural Sciences, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hik:diva-2949.
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Jackson, H. C. "The effects of opioids on central regulation of food and water intake." Thesis, Cardiff University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374735.
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Dubrow, Geoffrey Andrew. "Understanding Complex Flavor Percepts using Flavoromics." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1566064562976072.
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Petersen, Brent. "Biochemistry and Application of Exopolysaccharide Production in Mozzarella Cheese Starter Cultures." DigitalCommons@USU, 2001. https://digitalcommons.usu.edu/etd/5482.
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This study sought to investigate the role of the C55 undecaprenol lipid carrier in the production of exopolysaccharide (EPS), the effect of exopolysaccharide producing (EPS+) starter cultures on the viscosity of Mozzarella cheese whey, and the possible protective characteristics of capsular EPS against freezing and freeze drying. Efforts to investigate the role of the lipid carrier in EPS production employed pAMbacA, a plasmid that encodes an enterococcallipid kinase that confers bacitracin resistance by increasing intracellular levels of undecaprenol phosphate lipid carrier. Unfortunately, this avenue of study was thwarted by the inability to demonstrate bacA expression in a model dairy lactic acid bacterium, Lactococcus lactis.
To study the effect of EPS+ cultures on cheese whey, Mozzarella cheese was made with starters consisting of Lactobacillus helveticus (LH100) paired with one of four Streptococcus thermophilus strains. These strains included a capsular EPS producer (Cps+) MR-1C; a non-exopolysaccharide producing negative mutant (EPS-) of MR-1C, DM10; a ropy EPS producer, MTC360; and a non-EPS producing industrial strain, TA061. Results showed that Mozzarella cheese made with a Cps+ or ropy EPS+ S. thermophilus strain had significantly higher moisture levels than cheese made with non-exopolysaccharide producing (EPS-) streptococci. Melt properties were also better in cheeses with higher moisture. Viscosity measurements of unconcentrated and ultrafiltered (5-fold concentrated) whey showed that ultrafiltered whey from cheeses made with S. thernzophilus MTC360 was significantly higher in viscosity than whey from cheeses made with MR-1C, TA061, or DM10. There was no significant difference in the viscosity of unconcentrated or concentrated whey from cheese made with S. thermophilus MR-1C and cheese made with the commercial starter culture TA061. The results indicated that non-ropy, encapsulated exopolysaccharideproducing S. thermophilus strains can be used to achieve higher cheese moisture levels and to improve the melt properties of Mozzarella cheese without significantly increasing cheese whey viscosity.
Finally, S. thermophilus MR-1C and DM10 were subjected to freezing and freeze drying to test for possible protective effects of the capsular exopolysaccharide. Analysis of variance of cell counts taken before and after freezing or freeze drying cycles revealed there was no significant difference between the viability of these strains.
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Jung, Hoon. "Effects of Micrococci on Improving Sensory Acceptability of Mutton Summer Sausage." DigitalCommons@USU, 1986. https://digitalcommons.usu.edu/etd/5331.
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The effects of micrococci on sensory characteristics of different batches of summer sausages were determined. Sixty four salt-tolerant indigenous isolates were selected from beef or mutton treated with 1.5 or 3.0% sodium chloride and 120 ppm sodium nitrite, and held at 5 or 10 C for 5 days. These isolates (61/64) were identified as staphylococci and micrococci. Summer sausages were made from several lamb, ewe, and ram carcasses which were hand deboned and blended after grinding to contain 22% fat. Six summer sausage treatments were prepared using two different sources of commercial starter cultures including Micrococcus species or Micrococcus varians and Lactobacillus plantarum, an indigenous Micrococcus isolate, a microbial lipase, or encapsulated lactic acid.
Three sensory panel sessions rated these products for consumer acceptability. Sensory panel results indicated that starter culture treatments did not improve sensory characteristics of the summer sausage over the treatment containing encapsulated lactic acid. Lipase addition caused a general reduction in sensory panel ratings for flavor, texture, appearance, and overall acceptability of the summer sausage (p = 0.05).
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Wood, Alisha M. "Addition of Three Dietary Fibers in an Extruded Whey and Cornstarch Expanded Snack Food." DigitalCommons@USU, 2006. https://digitalcommons.usu.edu/etd/5538.
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Different fiber types were incorporated in an extruded expanded high-protein snack food. Three dietary fibers (powdered cellulose, wheat fiber, and oat fiber) were selected based on ease of extrusion, percent total dietary fiber, visible expansion, and commercial availability. A high-fiber, high-protein snack food containing whey protein, normal cornstarch, and pregelatinized waxy cornstarch was extruded using the three selected fibers. The fibers replaced the normal cornstarch at 30, 60, and 80% yielding extrudates with three fiber levels (18, 36, and 48%). Each treatment or combination of fiber type and extrudate fiber level was extruded in triplicate. A control with no fiber added was also extruded in triplicate.
Extrudate characteristics were evaluated on physical (expansion ratio, air cell size, density, and breaking force) and chemical (moisture content, water absorption index, water solubility index, water and total soluble protein , and water soluble carbohydrate) parameters. The physical and chemical characteristics of the extrudates were found to be greatly affected by combined interaction of the fiber type and level of fiber in the extrudate. As the amount of fiber in the extrudate increased, moisture content increased (p < 0.0001) associated with a decrease in expansion ratio (p < 0.0001), air cell size (p < 0.0001), and water solubility index (p = 0.0013) and increased extrudate density (p < 0.0001), breaking force (p < 0.0001), and water absorption index (p < 0.0001). Dependent extrusion parameters (pressure, motor torque, barrel and die temperature of the mix, barrel and die temperatures, residence time, and product flow rate) were recorded and analyzed. All dependent extrusion parameters were influenced by the level of fiber incorporation in the extrudates (p < 0.0001). The temperature at the die was also significantly influenced by the type of fiber used, and the level of fiber and fiber type interaction (p< 0.0001). Differences were deemed statistically significant at p < 0.05. The possibility exists to incorporate dietary fiber at levels > 30% in extruded whey and cornstarch products.
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Eriksson, Sune. "Acrylamide in food products : Identification, formation and analytical methodology." Doctoral thesis, Stockholm : Dept of environmental chemistry, Stockholm university, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-700.
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Wang, Zhengfang. "Thiol Protein/Peptide Modification by N-(Phenylseleno)phthalimide and Applications of Chemometrics in Organic Food Authentication." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1395159533.
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Romans, Katherine Nieves. "The role of cholecystokinin (CCK) in the control of food intake in the rat." Thesis, University of Portsmouth, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286087.
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Pule, Bellah Oreeditse. "Solid-phase extraction based sample preparation for the determination of drug and organic pollutant residue." Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1006711.
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This thesis presents solid phase extraction (SPE) methodologies based on mixed-mode polymeric sorbents; a mixed mode strong anion exchanger (Agilent SampliQ SAX) and a mixed mode strong cation exchanger (Agilent SampliQ SCX). Furthermore, dispersive-SPE based on a quick, easy, cheap, effective, rugged and safe (QuEChERS) method was assessed for applicability in the determination of drug residues. The mixed-mode polymeric sorbents were evaluated for the simultaneous fractionation of drugs that exhibit diverse polarities with acidic, basic and neutral functionalities in biological matrices (plasma and urine). The polymeric skeleton of these sorbents entails an exchanger group and therefore provides two retention mechanisms, strong cation or anion exchange retention mechanisms with hydrophobic interactions. It was demonstrated that with a sequential elution protocol for sample clean-up analytes were fractionated into acidic, basic and neutral classes. The SAX was employed for analysis of ketoprofen, naproxen (acidic drugs), nortriptyline (basic) and secobarbital (neutral) from urine sample. The SCX was used for fractionating phenobarbital, p-toluamide (acidic), amphetamine, m-toluidine (basic) and acetaminophen (neutral drug) from plasma sample. QuEChERS method was employed for quantitative determination of 16 polycyclic aromatic hydrocarbons (PAHs) from fish fillets and soil; 9 sulfonamides (SAs) from chicken muscles and acrylamide (AA) in cooking oil. The analyte recoveries ranged from 79.6 - 109% with RSDs ranging from 0.06 - 1.9% at three different fortification levels. Good linearity (r2 > 0.9990) was attained for most analytes. The limits of detection and quantification ranged from 0.03 - 0.84 μg/ml and 0.81 - 1.89 μg/ml respectively for analytes in biological samples. LODs and LOQs for analytes in food and environmental samples ranged from 0.02 to 0.39 and 0.25 to 1.30 ng/g respectively.
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Fife, Robert Lloyd. "The Influence of Fat and Water on the Melted Cheese Characteristics of Mozzarella Cheese." DigitalCommons@USU, 2003. https://digitalcommons.usu.edu/etd/5492.
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The effect of reducing the fat content of low-moisture part-skim Mozzarella cheese from 19% to less than 5% on melted cheese properties, i.e., apparent viscosity, cheese melt, and cook color, was investigated. Functional properties of melt and stretch and cook color were evaluated at d 1, 7, 14, and 28. A rapid microwave oven method underestimated the moisture content of the low fat cheeses by approximately 10%. Low fat cheese did not melt as well as did the low-moisture part-skim Mozzarella cheese although the moisture content of the low fat cheese (moisture content ranged from 62.5% to 63.6%) was greater than the moisture content of the part-skim control (52.1 %). Storage for 28 d only marginally increased the meltability of low fat cheese. Lower fat content increased cook color. The amount of intact a αs-CN decreased by at least 48% in all cheeses as a result of proteolysis during 28 d of storage.
The relative proportion of bound, entrapped, and expressible water was determined for a reduced-fat (8% fat) and control (19% fat) Mozzarella cheese on d 1, 7, 14, and 21 of refrigerated storage. Changes in the state of water were related to changes in cheese microstructure of a commercial Mozzarella cheese and to changes in cheese meltability of the control cheese. The amount of expressible water was proportional to fat content. Throughout storage, fat/serum channels became smaller and the protein matrix expanded into the areas between fat globules. The meltability of both cheeses increased during storage. Both cheeses contained 0.71g bound water/ g protein. Expressible water decreased in both cheeses until by d 21 no water was expressible. Entrapped moisture increased from approximately 10% to 60% for the control cheese and from approximately 33% to 50% for the reduced-fat cheese.
An objective test was developed for measuring stretch, a characteristic of melted cheese. Three nonfat and four low-moisture part-skim cheeses were evaluated using the new test and the results compared with conventional test methods. Two new melted cheese parameters were defined: melt strength, the maximum load (g) obtained during the test, and stretch quality, the average load (g) as the cheese fibers stretched and elongated. Melt strength correlated with apparent viscosity. Stretch quality was determined for selected nonfat and low-moisture part-skim cheeses. A three-pronged probe was used to pull cheese vertically from a melted cheese pool. Use of this elongation stretch test, along with more traditional melted cheese tests, provides more complete information about the functional properties of Mozzarella cheese.
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Ocampo-Garcia, Jorge Ricardo. "Cottage Cheese from Ultrafiltered Skimmilk by Direct Acidification." DigitalCommons@USU, 1987. https://digitalcommons.usu.edu/etd/5344.
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Pasteurized skimmilk at 4°C was acidified to pH 5.8 with 85.5% phosphoric acid (136g H3Po4;100 kg skimmilk), then warmed to 54°C and ultrafiltered to a protein concentration 9.1 ± 0.2%. The retentate was heated to 76.5°C for 16 s then cooled to 2°C. Phosphoric acid (85.5%) was added at a rate of 3.41g per kg retentate. The acidified retentate was slowly warmed to 29.5 °C (3°C/5 min) when the pH was checked. The pH at this point was no lower than 5.4. Heating was continued until a temperature of 32.2°C was reached. Glucono delta lactone was added to the retentate (17.6 g/kg retentate) and left undisturbed for approximately 80 min. The curd was cut at pH 4.7 with 0.64 cm curd knives and allowed 10 min for syneresis. Permeate obtained from the same lot of milk was acidified to pH 4.8 (66 g H3Po4;100 kg permeate), then added to the curd at 32.2°C (three parts permeate to four parts retentate) and used as a cooking vehicle. The curd was cooked to 59°C in 90 min. The curd was held at 59°C for 10 min, drained and washed once with ice water. Cream dressing containing 12.5% fat and 3% salt was used at the rate of two parts curd to one part dressing.
Control cottage cheese was produced by a direct acid method from the same skimmilk used to produce ultrafiltered curd.
Use of ultrafiltered skimmilk retentate for cottage cheese making resulted in 2.24% more curd (corrected to 20% solids) and 2.24% more curd per kg original milk protein than the control. However, satisfactory firmness in UF curd required slightly more than 20% solids in the final product. Sensory evaluations indicated that creamed cottage cheese was not significantly different (p
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Koosis, Aeneas. "THERMAL, INTERFACIAL, AND APPLICATION PROPERTIES OF PEA PROTEIN MODIFIED WITH HIGH INTENSITY ULTRASOUND." UKnowledge, 2019. https://uknowledge.uky.edu/animalsci_etds/107.
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The overall objective of the study was to investigate different food ingredient conditions and ultrasound treatment on pea protein in terms of surface morphology and thermal characteristics. The motivation of this work was based on previous studies focusing on non-chemical physical modifications of plant proteins and the increasing demand for functional alternative proteins.
Ultrasonication time and amplitude, pH, protein concentration, and salt concentration all influenced the thermal and interfacial properties of pea protein. Ultrasound treatment altered the quaternary and tertiary structure of the storage protein and disrupted non-covalent bonds. The structural altercations and a reduction in particle size led to improved functionality.
For foams generated at pH 5.0 with 4% (w/v) ultrasound treated protein, the foams had acceptable capacity and stability even when high levels of sugar (5% sucrose) and salt (0.6 M) were incorporated. An acceptable angel food cake simulation can be achieved by replacing egg white with ultrasound treated pea protein. Color and loaf height were different, but similar texture profiles were achieved.
Ultrasound treatment significant improved the emulsifying capacity (up to 1.4 fold), emulsion stability, and creaming index compared to control samples (no ultrasound) over two weeks. The ultrasound treated emulsion yielded lower TBARS values, likely due to the change in exposed protein reactive groups.
These findings demonstrate that ultrasound processing is an effective nonchemical method to change the structural and physiochemical properties of pea protein. Pea protein processed with this method might allow for the functionality in a bakery, dressings, or beverage products, which is appealing to many consumers and manufacturers.
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Mulaudzi, Ludwig Vusimuzi. "Application of flow injection in the assay of selected substances in food and clinical analysis." Diss., Pretoria : [s.n.], 1999. http://upetd.up.ac.za/thesis/available/etd-11162006-163430/.
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GOSETTI, FABIO. "Methods of analysis and control in food chemistry by chromatographic techniques with UV-Vis and mass spectrometry detections." Doctoral thesis, Università degli Studi del Piemonte Orientale, 2005. http://hdl.handle.net/10281/255650.
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Investigation in food science and technology, both by the food industry and governmental agencies, is based on the evaluation of food composition and characteristics. All food products require analysis as part of a quality management program that involves the development, the production processes and the control of the commercial product. The chemical composition and physical properties of food are necessary to evaluate the nutritive value, the functional characteristics and the acceptability of the food product. The nature of the sample and the specific use of the analysis dictate the choice of the analytical methods. Speed, precision, accuracy and ruggedness are often key factors in this choice. In any case the validation of the method for the specific food matrix is necessary to ensure the reliability of the method. Moreover, the success of any analytical method relies on the proper sampling selection and preparation of the food sample, on the careful execution of the analysis, and on the appropriate treatment and interpretation of the data. Methods of analysis developed and endorsed by nonprofit scientific organizations allow for standardized comparisons of the results between different laboratories, and for the evaluation of standard procedures. The official methods for the analysis of foods must ensure to meet the legal requirements established by governmental agencies. Food analysis can be defined as the discipline dealing with the development, application and comparison of the analytical procedures for characterizing the properties of foods and their constituents.
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Vasavada, Mihir. "Use of Natural Antioxidants to Control Oxidative Rancidity in Cooked Meats." DigitalCommons@USU, 2006. https://digitalcommons.usu.edu/etd/5528.
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The research in this dissertation focused on determining antioxidant effects of various natural antioxidants in cooked meat systems. Milk mineral (MM), spices, and raisin paste were used in cooked meat systems to verify their potential antioxidant properties.
The MM study determined the antioxidant activity of 1.5% MM added to uncured cooked beef meatballs, and possible additive effects of MM in combination with 20-ppm or 40-ppm sodium nitrate in cooked beef sausages . There was no additive inhibition of lipid oxidation in samples containing 20-ppm or 40-ppm sodium nitrite plus 1.5% MM. Cooked meat yield was not different between control meatballs and those containing MM. As expected, treatments containing nitrite had higher redness (a*) values than samples without nitrite. The MM at 1.5% was a very effective antioxidant as compared to controls.
The Garam Masala (GM) study determined the antioxidant effects and sensory attributes of the individual spices in an Indian spice blend GM in cooked ground beef, and possible additive antioxidant effects between Type I and Type II antioxidants. All spices had antioxidant effects on cooked ground beef, compared to controls without spices, with cloves being the most effective. All spices at their lowest effective recommended level effectively lowered the perception of rancid odor and rancid flavor in cooked ground beef as compared to control samples. As expected, most spices also imparted distinctive flavors to the cooked ground beef. Type II antioxidants (iron binding phosphate compounds) were more effective than individual Type I antioxidants (spices and butylated hydroxytoluene; BHT) in cooked ground beef. There was a positive additive antioxidant effect seen with rosemary + MM and rosemary + sodium tripolyphosphate (STPP) treatments as compared to individual rosemary treatment. There was no additive antioxidant effect observed for other combinations of spices with phosphate antioxidants.
The raisin study was done to determine the antioxidant activity of raisin paste added to cooked ground beef, pork, and chicken. Thiobarbituric acid (TBA) values were measured using the distillation method, on the distillates, to avoid interference from sugar in the raisins. Beef, pork, and chicken flavor intensity, rancid flavor intensity, and raisin flavor intensity were evaluated by a trained sensory panel (n = 6). Addition of 2% raisin paste effectively inhibited rancid flavor development for 14 days after cooking in cooked ground beef, pork, and chicken. Sugar added at levels equivalent to that contributed by the raisins inhibited rancidity, probably due to antioxidant effects of Maillard browning products, suggesting that the antioxidant effect of raisins was due to their sugar content.
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Heaton, Kevin M. "Establishing Threshold Levels of Nitrite Causing Pinking of Cooked Meat." DigitalCommons@USU, 1998. https://digitalcommons.usu.edu/etd/5456.
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Sporadic problems with pink color defect, or pinking, has occurred in cooked meat products for decades. Pink color can be due to the presence of undenatured myoglobin, denatured globin hemochromes, or nitrosylhemochrome. This research documented the level of added nitrite that produced nitrosylhemochrome in processed meat rolls from fabricated beef round, pork shoulder, turkey breast, and chicken breast. For each meat type, preliminary studies were conducted to narrow the range at which added nitrite caused pinking. Subsequently, the nitrite levels were increased incrementally by 1-ppm, and pink color was measured by trained panelists and by a Hunter color meter. Nitrosylhemochrome content was determined by acetone extraction.
Panel and instrumental measurements identified pink color in beef samples formulated with 14-ppm nitrite; nitrosohemochrome extracts detected pigment at 12- ppm. Nitrite levels that caused pinking in pork shoulder were much lower than in beef. Panelists identified pink color at 4-ppm nitrite, and Hunter color meter values showed increased redness at 6-ppm. Pigment extraction detected nitrosylhemochrome at 4- ppm added nitrite. The trained panel and Hunter color meter detected pink color in turkey breast at 2-ppm added nitrite; nitrosohemochrome extraction detected pink pigment at 3-ppm added nitrite. In chicken breast, pink color was detected visually and instrumentally at 1-ppm added nitrite. Pigment extraction detected nitrosylhemochrome at 2-ppm added nitrite. Lower levels of nitrite (1-3-ppm) caused pinking in light-colored meats (turkey and chicken breast, meats with total pigment between 19-ppm and 27-ppm). Higher levels of nitrite (5-14-ppm) caused pink color defect in dark pigmented meat (beef round and pork shoulder, meats with total pigment levels between 56-ppm and 147-ppm). Regression analysis was used to relate total pigment and the minimum level of nitrite causing pinking. The minimum nitrite level causing pinking was the lowest level of nitrite at which the trained panel, acetone extraction, and instrumental results detected pink color or nitrosyl pigment. The formula obtained from the model was as follows: Y = 0.092X + 0.53, where "Y" is the minimum level of added nitrite to cause pinking and "X" is the total pigment of the meat. This formula can be used to estimate the level of nitrite that can be expected to cause pinking in a wide range of pigmented meats.
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Ghann, William Emmanuel. "Studies of Surfactants Effect on Riboflavin Fluorescence and Its Determination in Commercial Food Products and Vitamin Tablets." Digital Commons @ East Tennessee State University, 2008. https://dc.etsu.edu/etd/2000.
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A simple and economical fluorometer using blue LEDs excitation sources and simple PMT detection had been built, assembled, optimized, and employed for measurement of fluorescence from riboflavin (vitamin B2). Surfactants have been known to enhance the intensity of fluorescence of fluorescent compounds. Fluorescence analysis of riboflavin in the presence of various anionic, cationic, and nonionic surfactants was also conducted to determine if they could improve analysis. However, the surfactants employed did not seem to have any meaningful enhancement; in fact, some actually diminished the fluorescence intensity of riboflavin. The procedure was linear for riboflavin from 0.01 to 2.5 μg/mL. Reproducibility expressed as relative standard deviation was about 2%. The recoveries obtained range from 91.3% to 100.21% for the samples determined. The proposed method was successfully applied to the analysis of riboflavin in commercial vitamin tablets and cereal products. The results obtained were consistent with expected values as provided by the manufacturers. The method is simple, sensitive, economical, and rapid.
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Hwang, Seokhwan. "Anaerobic Treatment of Whey Permeate Using Upflow Sludge Blanket Bioreactors." DigitalCommons@USU, 1993. https://digitalcommons.usu.edu/etd/5400.
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Whey permeate was anaerobically digested in laboratory scale upflow anaerobic sludge blanket reactors. Nine hydraulic retention times between 5 and 0.2 days were examined with a fixed influent concentration of 10.6 ± 0.2 g COD/L.
Chemical oxygen demand removal efficiency ranged from 99.0 to 18.9% and maximum production rate of methane gas was 2.67 L/L/day at a hydraulic loading rate of 12.97 kg COD/m3/day. About 70% of the chemical oxygen demand removed was converted to methane.
Both the nonlinear least square method with 95% confidence interval and linear regression were used to evaluate kinetic coefficients. The maximum substrate utilization rate, k, and half saturation coefficient, KL, were determined to be 1.269 ± 0.163 Kg COD/kg VSS/day and 1.000 ± 0.179 kg COD/kg VSS/day. The yield coefficient, Y, and biomass decay rate coefficient, Kd, were also determined to be 0.160 ± 0.012 kg VSS/kg COD and 0.027 ± 0.004 day-1, respectively.
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Junior, João de Araújo. "Análise térmica e ensaios de colagem de adesivos \"hot melt\" para embalagens de congelados." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/46/46132/tde-05072018-121818/.
Full textAbstract:
Os adesivos \"hot melt\" são blendas poliméricas aplicadas no estado fundido para fechamento de embalagens. Neste trabalho, procedemos à análise térmica e ensaios de adesão de alguns adesivos \"hot melt\" desenvolvidos para embalagens de alimentos congelados, buscando as formulações de melhor estabilidade térmica na temperatura de aplicação (180 ºC) e desempenho de colagem na temperatura do freezer. Estes adesivos contêm diferentes matérias-primas, tais como copolímeros de etileno e acetato de vinila (EVA), resinas promotoras de adesão e ceras. As técnicas utilizadas para as análises térmicas foram a termogravimetria (TG) e a calorimetria exploratória diferencial (DSC). Para avaliação das colagens, foi utilizado um dinamômetro. Das análises de calorimetria exploratória diferencial foi possível concluir que a miscibilidade da resina nas blendas estudadas pode ser monitorada pelo maior ou menor deslocamento da Tg do EVA. Os ensaios mecânicos de colagem a -18 ºC mostraram que a miscibilidade destes sistemas, que tem impacto direto sobre sua Tg, é responsável pela melhor ou pior performance adesiva. A blenda contendo uma resina terpênica-fenólica (TP 2040), altamente imiscível, apresentou o melhor resultado de tração de descascamento a -18 ºC. Já a blenda contendo um éster de pentaeritritol (RE 100 L), de alta miscibilidade, foi a que teve resultado menos satisfatório neste teste. A calorimetria exploratória diferencial, assim como a termogravimetria, se mostraram importantes ferramentas para avaliação da estabilidade térmica dos adesivos. A blenda contendo EVA, um oligômero de ciclopenteno e uma cera sintética foi a que apresentou maior estabilidade térmica.The \"hot melt\" adhesives are polymeric blends applied in the molten state for case and carton sealing. In the present work, we carried out the thermal analysis and bonding evaluations of some hot melt adhesives for freezer grade carton sealing. These adhesives contained different raw materials, such as ethylene / vinyl acetate copolymers (EVA), tackfying resins and waxes, and we pursued the formulations with the best pot life in the application temperature (180 ºC) and bonding performance in the blast freezer temperature (-18 ºC). The techniques used for the thermal analysis were the thermogravimetric analysis (TGA) and the differential scanning calorimetry (DSC). For the bonding assessments, a dynamometer was used. From the DSC curves it was possible to figure out that the miscibility of the resin in the blends can be monitored by the EVA\'s Tg displacement. The bonding force analysis at -18 ºC showed that the miscibility of these systems is responsible for the adhesive performance. The blend containing a terpene-phenolic resin (TP 2040), highly imiscible, had the best result of peeling resistance whereas the blend containing a pentaerythritol ester of rosin (RE 100 L), a very miscible resin, was the one with the less satisfactory result. The thermogravimetry and the differential scanning calorimetry were important tools for the evaluation of the thermal stability of the adhesives. The blend containing an oligomer of cyclopentene presented the best thermal stability.
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Letzelter, Nathalie. "Development of FT-IR and raman spectroscopies for the quantitative analysis of single seeds." Thesis, University of East Anglia, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240254.
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O'Niones, Kevin J. "RHEOLOGICAL, FOAM, AND PHYSICAL PROPERTIES OF LOW SUCROSE MERINGUE AND ANGEL FOOD CAKE FORMULATED WITH NON-NUTRITIVE SWEETENERS AND POLYDEXTROSE." UKnowledge, 2014. http://uknowledge.uky.edu/animalsci_etds/35.
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The object of this research was to determine if an acceptable angel food cake alternative could be produced that had reduced calories and sucrose content. This was accomplished through replacing sucrose in meringue, angel food cake batter, and baked angel food cakes with polydextrose and either sucralose, acesulfame-K, or Rebaudioside A at different replacement levels (25, 50, 75, 100%). Meringue and cake batter properties were measured using rheological techniques. Baked angel food cakes were analyzed based on height, weight loss, moisture content, color, and TPA analysis. With meringue batter, 100% sucrose replacement was unacceptable since undissolved polydextrose made analyzing and end products impractical. While 75% sucralose and acesulfame-K sucrose replacement exhibited comparable air incorporation to the sucrose control in cake batter, baked angel food cakes showed a decrease in functional properties. Polydextrose was likely the cause. 25% sucralose and acesulfame-K sucrose replacement were no different from sucrose cakes in regards to height, overall textural appearance, crumb pore size, and hardness. These cakes resulted in an overall calorie reduction of 18.7%. In every experiment, Rebaudioside A replacement treatments exhibited trends opposite of sucralose and acesulfame-K treatments. Rebaudioside A treatments performed the worst for rheological properties and TPA analysis.
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Jayasingh, Preetha. "Prevention of Pigment Deterioration and Lipid Oxidation in Ground Beef and Pork." DigitalCommons@USU, 2004. https://digitalcommons.usu.edu/etd/5506.
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Fresh beef was modified-atmosphere packaged in carbon monoxide or oxygen to prolong red surface color. After comparison of several packaging method using carbon monoxide, steaks pretreated with 5% carbon monoxide for 24 hours and then vacuum packaged had the best combination of color and microbial stability (5 weeks), with the least potential for carbon monoxide inhalation.
In the evaluation of ground beef in high-oxygen, modified-atmosphere-packaging, thiobarbituric-acid numbers increased over time, and the flavor was disliked slightly after 6 or 10 days of storage at 2° Celsius.
The antioxidant effect of milk-mineral was tested in raw and cooked ground pork stored refrigerated or frozen. Thiobarbituric-acid numbers were low for all raw treatments. For cooked ground pork, thiobarbituric-acid numbers were lower for samples with milk-mineral or sodium-tripolyphosphate, compared to control or samples with butylated-hydroxytoluene. Sodium-tripolyphosphate, a type 2 antioxidant (iron chelator), was also very effective in preventing heme degradation during refrigerated storage.