Academic literature on the topic 'Guava - acid'

Made available in DSpace on 2014-07-29T15:22:57Z (GMT). No. of bitstreams: 1 Claudia munhoz.pdf: 644332 bytes, checksum: 80da90f86ec8e67bdffb9cd0bf254ba6 (MD5) Previous issue date: 2008-03-07<br>The objectives of this study were to characterize the raw material in nature, the flours of fractions of guava cv Pedro Sato and to optimize the factors that influence the yields of pectin extraction of flour of the guava pulp and pulp with peel. As characterize pectins obtained in optimal points on the degree of esterification, comparing them with the commercial pectin. Fruits were used for pectin.extraction. The fruits were divided in peel, pulp, pulp with peel and flesh, dry in stove with circulation of air. Samples in nature and drought were characterized physically and chemically. The central rotation composed design with four axial points and three replicates in the central point was used to optimize the extraction of pectin of flour of the guava pulp and pulp with peel. The extraction was performed in 4 g of flour to 200 mL of solution of citric acid at different concentrations and at different times of extraction, at temperature of 97 ° C. The esterification degree of extracted pectins was compared to commercial pectin one. The highest yields in the extractions of pectin of flour of the guava pulp and pulp with peel were obtained with citric acid solution at 5 g (100 g)-1 and the extraction time of 60 min. Pectins showed up with low esterification, with 38.94% for the pulp and 40.99% for pulp with peel of guava. However, pectins showed the concentration of galacturonic acid next to the commercial standard of 65% and they can be applied in foods with low soluble solids (diet or light food)<br>Os objetivos deste trabalho foram caracterizar a matéria-prima in natura, as farinhas das frações de goiaba cv Pedro Sato e otimizar os fatores que influenciam nos rendimentos de extração de pectina das farinhas de polpa e de polpa com casca de goiaba. Assim como caracterizar as pectinas obtidas nos pontos ótimos quanto ao grau de esterificação, comparando-as com a pectina comercial. Os frutos foram separados em casca, polpa, polpa com casca e miolo, secos em estufa com circulação de ar. Amostras in natura e secas foram caracterizadas física e quimicamente. O planejamento composto central rotacional com quatro pontos axiais e três repetições no ponto central foi utilizado para otimizar a extração de pectina das farinhas de polpa e de polpa com casca de goiaba. A extração foi realizada em 4 g de farinha para 200 mL de solução de ácido cítrico em diferentes concentrações e em diferentes tempos de extração, a temperatura de 97 ºC. As pectinas extraídas foram comparadas com pectina comercial quanto ao grau de esterificação. Os maiores rendimentos nas extrações de pectina das farinhas da polpa e da polpa com casca de goiaba foram obtidos com solução de ácido cítrico a 5 g (100 g)-1 e tempo de extração de 60 min. As pectinas apresentaram-se de baixa esterificação, com 38,94% para a polpa e 40,99% para a polpa com casca de goiaba. No entanto, as pectinas apresentaram concentração de ácido galacturônico próximo ao padrão comercial que é de 65%, podendo ser aplicadas em alimentos com baixo teor de sólidos solúveis (alimentos diet ou light)

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior<br>FundaÃÃo de Amparo a Pesquisa do Estado do PiauÃ<br>Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico<br>VÃrios estudos tÃm associado efeitos benÃficos à saÃde, ao consumo regular de frutos, vegetais, grÃos e à presenÃa de substÃncias antioxidantes nesses alimentos, assim, o presente trabalho objetivou avaliar as potencialidades biotecnolÃgicas da semente de goiaba (Psidium guajava L.), em pà atravÃs de tÃcnicas instrumentais cientificamente reconhecidas. Foram analisadas sementes de goiaba vermelha em pÃ, da variedade Paluma cedidas por uma indÃstria produtora de polpa congelada de frutos. Foram elaborados produtos de panificaÃÃo com substituiÃÃo de 5 e 10% da farinha de trigo pela semente de goiaba em pÃ, e avaliada a aceitabilidade e a intenÃÃo de compra. Foram realisadas anÃlise de composiÃÃo nutricional, compostos bioativos, qualidade microbiolÃgica e perfil de Ãcido graxo da semente de goiaba em pÃ. Extratos acetÃnico, etanÃlico e metanÃlico foram utilizados para quantificar os teores de fenÃlicos totais, flavanÃides totais, taninos totais, determinar a atividade antioxidante por diferentes mÃtodos in vitro (DPPH, sistema &#946;- caroteno/Ãcido linoleico e Rancimat) e avaliar a toxicidade frente à Artemia salina sp. Identificou-se e a quantificou-se por cromatografia lÃquida de alta eficiÃncia (CLAE) os compostos fenÃlicos no extrato acetato de etila. Os resultados permitiram comprovar que a substituiÃÃo de 5% e 10% de farinha de trigo na massa do bolo doce e na pizza sabor portuguesa apresentaram melhor aceitabilidade e intenÃÃo de compra, comparado ao produto sem substituiÃÃo. A composiÃÃo quÃmica e nutricional da semente de goiaba em pà exibiu quantidades variÃveis de macro e micronutrientes, com alta concentraÃÃo de fibra dietÃtica (63,94 g/100g), proteÃna (11,19 g/100g), ferro (13,8 mg/100g), zinco (3,31 mg/100g) e reduzido teor calÃrico (182 kcal/100g). Apresentou quantidades significativas de compostos bioativos como Ãcido ascÃrbico (87,44 mg/100g), carotenoides totais (1,25 mg/100 g), licopeno (182  0.09 Âg/100g) e fibra dietÃtica insolÃvel (63,55 g/100g). O perfil lipÃdico mostrou uma predominÃncia de Ãcido graxo insaturado (87,06%), especialmente Ãcido linolÃico (w6) e Ãcido olÃico (w9). NÃo apresentou contaminaÃÃo microbiana e nem toxicidade frente a Artemia salina sp. O extrato acetÃnico apresentou maior concentraÃÃo de compostos fenÃlicos, flavonÃides e taninos totais 49,70Â0,48 mgEAG/g; 1,529Â0,04 mgEQ/g; 41,159Â2,64 mgEAT/g, respectivamente. O extrato acetÃnico tambÃm obteve o maior poder antioxidante, no ensaio de DPPH, IC50 de 4,33Â0,08 Âg/mL. No sistema de autooxidaÃÃo do &#946;-caroteno/Ãc. linolÃico, o extrato etanÃlico (IC50 0,193Â0,07Âg/mL) apresentou atividade antioxidante estatisticamente semelhante ao BHT. Quanto ao ensaio de Rancimat, os extratos etanÃlico (6,41Â0,07 h) e acetÃnico (6,35Â0,00 h), conseguiram preservar a estabilidade oxidativa do Ãleo de soja por um perÃodo de tempo maior e estatisticamente nÃo diferiu do Ãleo de soja adicionado de BHT (6,44Â0,01 h). Dos compostos fenÃlicos identificados o resveratrol e a cumarina foram os que apresentaram maior concentraÃÃo, 39,0Â0,02 e 48,79Â0,02 mg/100g, respectivamente. Assim, conclui-se que a semente de goiaba em pà podem ser consideradas uma fonte barata e rica em compostos antioxidantes. Sua utilizaÃÃo seria uma alternativa viÃvel para evitar o desperdÃcio e contribuir para minimizar o impacto ambiental, alÃm da possibilidade de serem incorporados nas indÃstrias de alimentos, farmacÃuticas e nutracÃuticas<br>Several studies have associated beneficial effects on health to the regular consumption of fruits, vegetables, grains due to the presence of antioxidants in these foods, and so the present study aimed to evaluate the potential of biotech guava seed (Psidium guajava L.), and the main metabolites responsible for its antioxidant activity. Powder from red guava seeds was analyzed, made from the Paluma variety donated by an industry producing frozen fruit pulp. Bakery products were prepared with the substitution of 5 and 10% of wheat flour by guava seed powder, and the acceptability and purchase intent were measured. Analyses of nutritional composition, bioactive compounds, microbiological quality and profile fatty acid of the guava seed powder were carried out. Acetonic, ethanol and methanol extracts were used to quantify the levels of total phenolics, total flavonoids, tannins, to determine the antioxidant activity in different in vitro methods (DPPH, &#946;-carotene / linoleic acid system and Rancimat) and to evaluate the toxicity from Artemia salina sp. The phenolic compounds in ethyl acetate extract were identified and quantified by high performance liquid chromatography (HPLC). The results showed that replacing 5% and 10% of wheat flour in sweet cake and Portuguese flavor pizza dough showed better acceptability and purchase intention, compared to the product without replacements. The chemical and nutritional composition of guava seed powder exhibited varying amounts of macro and micronutrients, with a high concentration of dietary fiber (63.94 g/100 g), protein (11.19 g/100 g), iron (13.8 mg / 100 g), zinc (3.31 mg/100 g) and reduced calorie (182 kcal/100g). Significant amounts of bioactive compounds such as ascorbic acid (87.44 mg/100g), total carotenoids (1.25 mg/100 g), lycopene (182  0.09 &#956;g/100g) and insoluble dietary fiber (63.55 g/100 g) were also found. The lipid profile showed a predominance of unsaturated fatty acid (87.06%), especially linoleic acid (w6) and oleic acid (w9). a microbialogic test showed negative contamination, and no toxicity was found using Artemia salina sp. The acetonic extract showed the highest concentration of phenolic compounds, flavonoids and tannins 49.70  0.48 mgEAG / g; 1.529  0.04 mgEQ / g; 41.159  2.64 mgEAT / g, respectively. The acetonic extract also showed the highest antioxidant powder, in the DPPH assay, IC50 of 4.33  0.08 mg / mL. In the autoxidation of &#946;-caroteno/ linoleic acid system, the ethanol extract (IC50 0.193  0.07 mg / mL) showed antioxidant activity statistically similar to BHT. The Rancimat test, the ethanolic extracts (6.41  0.07 hr) and acetone (6.35  0.00 hr) were able to preserve the oxidative stability of soybean oil for a longer period of time and did not statistically differ from soybean oil added BHT (6.44  0.01 hr). Of the phenolic compounds identified, resveratrol and coumarin presented the highest concentrations, 39.0  0.02 and 48.79  0.02 mg/100g, respectively. Thus, it can be concluded that guava seed powder can be considered an abundant source of antioxidants. Its use would be a feasible alternative to avoid waste and contribute to minimizing the environmental impact, in addition to its incorporation in the food, pharmaceutical and nutraceutical industries.

碩士<br>國立成功大學<br>化學學系<br>83<br>Lipoxygenases (EC 1.13.11.12; abbrev.LOX) are a group of closely related enzymes that appear to be widely distributed in plants and mammalian tissues. This enzyme can catalyze the oxygenation ofpolyunsaturated fatty acids (PUFA) containing a cis, cis-l,4-pentadiene system. The nomenclature of the lipoxygenases is based upon the site of insertion of the oxygen molecule onto the fatty acid molecule. In the case of arachidonic acid (abbrev. AA), they have been classfied as 5-, 8-, 9-, 11-, 12-, and 15- lipoxygenase. The reaction of LOX with arachidonic acid can lead to hydroper- oxyeicosatetraenoic acids (abbrev. HPETEs) or leukotrienes (abbrev. LTs) in mammals. These eicosanoids are known to have various physiologic effects such as leukocytes agglomeration, vasoconstriction and hypersensi- tive reactions. When LOX reacts with polyunsaturated fatty acids such as linoleic acid and linolenic acid in plants, hydroperoxides of the unsaturated fatty acids are produced. These compounds play important roles in plant growth, development, senecence and defence against insects and pathogens. Thus, investigations on the various sources of LOX and their metabolites can not only result in great academic importance but also has significant economic value and human well-being. In this study, we employed guava (Psidium guajava L.) as a source of lipoxygenase. Guava LOX was extrated under potassium phosphate buffer (pH 6.0) and isolated by ammonium sulfate (65%) precipitation. This partially purified enzyme was subjectd to incubation (0℃) with AA in potassium phosphate buffer (pH 6.0). The products were extrated with chloform : methanoi (3:1, v/v) and purified with High Perfomance Liquid Chromatography (HPLC) to yield a sole product : 15-hydroperoxyei- cosatetafinoic acid (15-HPETE), in 72.7% yield. The identity of 15-HPETE was characterized by triphenylphosphine reduction to its corresponding hydroeicosatetraenoic acid (HETE), further analyzed with HPLC, and identified by GC/MS after proper derivatizations.

碩士<br>國立嘉義大學<br>食品科學系研究所<br>106<br>Guava seeds are by-products of guava (Psidium guajava L.) processed products such as juices, dried fruits, jams, etc, the by-products account for 10-15% of fresh fruit weight, their texture are hard and cannot be use effectively, however, due to the large output and still some functional ingredients inside, hope to make full use of the by-products and reduce the waste. Therefore, this experiment extracted the guava seeds produced during the processing of the juice with different extraction conditions, The results showed that the most suitable extraction conditions were water extraction at 121°C for 15 minutes and room temperature extraction using 50% ethanol for 24 hours, the extract yields were 4.2±0.18% and 2.58±0.2%, the functional components in the extract like total phenolic compounds content are 11.31±0.6 and 8.53±0.27 mg gallic acid/g, flavonoids content are 5.31±0.16 and 5.73±0.11 mg quercetin/g. In the antioxidant capacity test, the DPPH radical scavenging ability of the extract at the concentration of 10 mg/mL was 76.94±1.79% and 62.94±0.53%, respectively, while the total antioxidant capacity was 98.08±0.13% and 93.30± 0.83%. Roast the dry guava seeds at 200℃ for 5-15 minutes then ground, and use the most suitable extraction conditions, both water and ethanol extraction show the highest extract yields in roast 5 minutes group were 5.41±0.17% and 3.0±0.03%, both water and ethanol extraction show the highest functional components content in roast 15 minutes group, total phenolic compounds content are 37.20±2.94 and30.164±0.3 mg gallic acid/g, while the flavonoids content are 3.52±0.27and4.04±0.11 mg quercetin/g. In the antioxidant capacity test, the DPPH radical scavenging ability of the roast 15 minutes extract at the concentration of 10 mg/mL was 84.14±2.46% and 82.56±1.13%, while the total antioxidant capacity was 86.43±1.4% and 96.26±0.47%. All extracts had antibacterial activity against S. enterica, L. monocytogenes, S. aureus, E. coli, and V. parahaemolyticus, and had the best inhibitory effect against V. parahaemolyticus. The experiment found that the guava seed extract had no sugar digestive enzyme inhibitory ability but had the ability to accelerate the growth of lactic acid bacteria. The experiment assess the sugar digestive enzyme inhibitory ability of three plant origin latic acid bacteria, then added the guava seeds extracts as prebiotics, results showed that can increase the α-glucosidas inhibition of the supernatant from three plant origin latic acid bacteria, and the suspension from L. fermentum BCRC 12190, but decrease the α-glucosidas inhibition of the suspension from L. plantarum BCRC 10357 and L. brevis BCRC 12187. It also increase the α-amylase inhibition of all suspensions from three plant origin latic acid bacteria, and show significant differences wihe the control (p<0.05).