Orientador: Celio Kenji Miyasaka / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-15T19:03:10Z (GMT). No. of bitstreams: 1 Abecia-Soria_MariaInes_D.pdf: 1397720 bytes, checksum: efabd9293a2a8d45841c5d131da10056 (MD5) Previous issue date: 2010 / Resumo: As proteínas do soro de leite são consideradas de alto valor nutritivo. Elas têm escore químico superior às de outras proteínas de origem animal, possuem elevadas concentrações de aminoácidos de cadeia ramificada (BCAA), com excelente balanço e biodisponibilidade de aminoácidos essenciais. As proteínas de soro de leite vêm sendo largamente utilizadas pela indústria de alimentos como suplemento na alimentação de esportistas, devido às suas características fisiológicas e funcionais, destacando-se o uso dos hidrolisados, que tem sido recomendado para situações de estresse metabólico como o exercício físico em que a reposição de proteínas no organismo se torna necessária. O presente trabalho teve como objetivo avaliar alterações metabólicas induzidas pelo consumo de proteínas do soro de leite [isolado (ISL) e seu hidrolisado (HSL) com grau de hidrólise 10%] em comparação com a dieta padrão [caseína (CAS)], utilizadas como única fonte protéica em ratos submetidos ao exercício físico. Foram utilizados 96 ratos machos Wistar (~100g) divididos em grupos segundo o tipo de dieta (CAS, ISL e HSL) e a intensidade do exercício físico [treinados (T), treinados exaustos (TEX), sedentários (S) e sedentários exaustos (SEX)] durante 35 dias. Os seguintes parâmetros foram analisados: tempo de exaustão, concentração de lactato no sangue, glicogênio hepático (GH) e muscular (GM), atividade das enzimas marcadoras de lesão tecidual, incluindo lactato desidrogenase (LDH), creatina quinase (CK), alanina e aspartato aminotranferase (ALT e AST, respectivamente). Os animais alimentados com HSL nos grupos TEX e SEX conseguiram correr por muito mais tempo até atingir a exaustão em relação aos que receberam as dietas com CAS e ISL (p<0.05). O tempo de exaustão em relação à dieta CAS foi 72 min maior no grupo TEX e 44 min maior no grupo SEX. A diferença no tempo de exaustão entre os animais alimentados com as dietas de HSL e ISL foi de 40 min. no grupo TEX e de 13 min no grupo SEX. A concentração de lactato dos animais alimentados com ISL e HSL foi significativamente menor em relação aos alimentados com CAS nos grupos T e S (p<0,05). A concentração de glicogênio hepático dos animais que receberam as dietas com ISL e HSL foi estatisticamente superior em comparação com os que consumiram CAS nos grupos T(46%) e S (61%). A concentração de glicogênio muscular não apresentou diferenças significativas entre as três dietas nos diferentes grupos de treinamento (TEX, SEX, T e S). A atividade da ALT dos animais que consumiram HSL nos grupos SEX e S foi estatisticamente menor que os que receberam CAS. A atividade da AST dos animais alimentados com HSL foi significativamente menor que a dos que consumiram a dieta com CAS nos diferentes grupos de treinamento (TEX, SEX, T e S). A atividade da CK e LDH dos ratos que receberam a dieta com HSL foi estatisticamente menor que dos alimentados com CAS em todos os grupos de treinamento exceto no grupo S. Dos resultados obtidos neste trabalho pode-se concluir que o uso das proteínas do soro de leite [principalmente o hidrolisado (10% grau de hidrólise)] em relação à proteína padrão (CAS) como única fonte protéica em ratos submetidos a exercício físico, promoveu a) menor ganho de peso em todos os grupos, b) maior resistência à exaustão tanto no grupo TEX como no SEX, c) maior concentração de glicogênio hepático nos grupos T e S e d) maior proteção contra possíveis lesões hepáticas e musculares nos diferentes grupos estudados (TEX, SEX, T e S) / Abstract: The milk whey proteins are considered to be of high nutritive value and superior chemical score in comparison to other proteins of animal origin. They have high concentrations of branched-chain amino acids (BCAA) with excellent balance and bioavailability of essential amino acids. The milk whey proteins are widely used in the food industry as supplements for sportsmen due to their physiological and functional properties, and their hydrolysates are thought to be more efficient in the recovery of debilitated organisms under pronounced catabolic state because of their great stimulation to protein synthesis. In view of the energy value of proteins in exhaustive exercise, several studies on exercise and protein metabolism have been carried out in the attempt to elucidate the proper amount of protein that must be consumed by sportsmen. The present work had the objective of evaluating the metabolic changes induced by consumption of milk whey proteins [isolate (WPI) and its hydrolysate (WPH) with hydrolysis degree 10%] used as the only protein source in comparison to the standard diet [casein (CAS)] in rats submitted to physical exercise. 96 male Wistar rats (~100g) were divided in groups according to the type of diet (CAS, ISL and HSL) and the intensity of physical exercise [trained (T), trained taken to exhaustion (TEX), sedentary (S) and sedentary exhausted (SEX)] during 35 days. The following parameters were analyzed: time of exhaustion (min.), blood lactate concentration (mmol/L), liver glycogen (LG) and muscular glycogen (MG) (g/100g of tissue), activity of tissue injury marker enzymes (U/L) including lactate desidrogenase (LDH), creatine kinase (CK) and alanine and aspartate aminotranferase (ALT and AST respectively). The results showed that the animals fed with HSL in the groups TEX and SEX ran for much longer times until exhaustion in relation to the ones that received the diets with CAS and ISL (p<0.05). The exhaustion time in relation to the CAS diet was 72 min longer for the TEX group and 44 min longer for the SEX group. The difference in exhaustion time between the animals fed with the WPH and WPI diets was of 40 min for the group TEX and 13 min for the SEX group. The lactate concentration in the animals fed with WPI and WPH was statistically lower than in the ones fed with CAS in the groups T and S (p99<0,05). The concentration of liver glycogen in the animals that received the diets with WPI and WPH was statistically higher than in the animals that consumed CAS in the groups T (46%) and S (61%). The concentration of muscular glycogen did not have significant differences between the three types of diet in the different groups of training (TEX, SEX, T and S). The activity of the ALT of the animals that consumed WPH in the groups SEX and S was statistically lower than that of the animals that received CAS. The activity of the AST of the animals fed with WPH was significantly lower than that of the animals that consumed the diet with CAS in all of the groups of training (TEX, SEX, T and S). The activity of CK and LDH in the rats fed with HSL diet was statistical lower than in the ones fed with CAS in all of the groups of training except in the group S. From the results obtained in this work it can be concluded that the use of milk whey proteins [mainly the whey protein hydrolysate (10% hydrolysis degree)] in relation to the standard protein (CAS) as the only protein source in rats submitted to physical exercise promoted a) lesser weight gain in all of the groups, b) higher resistance to exhaustion in groups TEX and SEX, c) higher hepatic glycogen concentration in groups T and S and d) higher protection against possible hepatic and muscular injuries in all of the studied groups (TEX, SEX, T and S) / Doutorado / Nutrição Experimental e Aplicada à Tecnologia de Alimentos / Doutor em Alimentos e Nutrição

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2017-12-20T13:20:23Z No. of bitstreams: 1 israelnovaesdemoura.pdf: 1420476 bytes, checksum: 6634c39e49385490d2f7b019fb451af1 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-12-21T11:59:42Z (GMT) No. of bitstreams: 1 israelnovaesdemoura.pdf: 1420476 bytes, checksum: 6634c39e49385490d2f7b019fb451af1 (MD5) / Made available in DSpace on 2017-12-21T11:59:42Z (GMT). No. of bitstreams: 1 israelnovaesdemoura.pdf: 1420476 bytes, checksum: 6634c39e49385490d2f7b019fb451af1 (MD5) Previous issue date: 2017-08-04 / O objetivo deste trabalho foi avaliar a caracterização e eficácia de diferentes técnicas da espectroscopia de fluorescência na detecção de adulterações em formulações de Whey Protein concentrado (WPC) em pó, a partir de sua mistura com substâncias de diferentes origens. Foram estudados dois diferentes lotes de WPC provenientes do mesmo fornecedor. Adulterações foram realizadas a partir da adição individual de Cafeína (Tratamento 1), Creatina (Tratamento 2) e Lactose (Tratamento 3) a 30% (m/m) em WPC e submetidas às análises de espectroscopia de fluorescência estacionária e resolvida no tempo, utilizando-se os comprimentos de onda de excitação de 275 e 335 nm. Quando excitadas a 275 nm, as amostras apresentaram pico de emissão a 335 nm aproximadamente, com uma banda de emissão em torno de 380 nm, característica apenas na amostra contendo cafeína, enquanto lactose e creatina não induziram alterações no espectro do WPC. Quando excitadas a 335 nm, as amostras apresentam picos de emissão com máximo em 425 e 470 nm, sem diferenciação por simples observação do espectro. Análise da distância Euclidiana evidenciou que, quando excitadas a 275 nm, os espectros completos dos tratamentos 2 e 3 foram semelhantes ao Controle 1 enquanto o Tratamento 1 foi diferente. Já na excitação a 335 nm todos os espectros foram semelhantes. Análise de Componentes Principais (PCA) confirmou a diferenciação do Tratamento 1 a 275 nm mas foi inconclusiva com a excitação de 335 nm, porém determinou pontos de interesse para estudos das derivadas dos espectros. Com as derivadas, foi possível a diferenciação entre os Tratamentos 2 e 3 nos dois comprimentos de onda, com enfoque em comprimentos de ondas específicos que podem ser decisivos na diferenciação das adulterações. Em relação a espectroscopia resolvida no tempo, o Tratamento 1 demonstrou valores da intensidade média do tempo de vida de emissão superior aos tratamentos 2 e 3 nos dois comprimentos de onda de excitação empregados. A adulteração com cafeína foi realizada na amostra Controle 2 e foi observado resultado semelhante quando comparada ao Controle 1. De maneira geral, a aplicação das técnicas de espectroscopia de fluorescência estacionária e resolvida no tempo possibilitou a caracterização das amostras utilizadas no estudo. Além disso, possibilitou a observação de diferenças entre as amostras controles e aquelas adulteradas, especialmente a adicionada de cafeína e excitada no comprimento de onda 275 nm, com ajuda de ferramentas matemáticas. Os resultados aqui obtidos corroboram com o fato de que as técnicas empregadas podem ser importantes na detecção de fraudes em produtos lácteos. / The objective of this work was to evaluate the characterization and efficacy of different fluorescence spectroscopy techniques in the detection of adulterations in formulations of Whey Protein Concentrate (WPC) powder, from its mixture with substances of different origins. Two different batches of WPC from the same supplier were studied. Adulterations were performed from the individual addition of Caffeine (Treatment 1), Creatine (Treatment 2) and Lactose (Treatment 3) at 30% (w / w) in WPC and subjected to stationary fluorescence spectroscopy and time-resolved fluorescence, using the excitation wavelengths of 275 and 335 nm. When excited at 275 nm, the samples showed an emission peak at approximately 335 nm, with an emission band around 380 nm, characteristic only in the sample containing caffeine, while lactose and creatine did not induce alterations in the WPC spectrum. When excited at 335 nm, the samples showed peak emission at 425 and 470 nm, without differentiation by simple observation of the spectrum. Euclidean distance analysis showed that, when excited at 275 nm, the complete spectra of treatments 2 and 3 were similar to Control 1 while Treatment 1 was different. Regarding the excitation at 335 nm, all spectra were similar. Principal Component Analysis (PCA) confirmed the differentiation of Treatment 1 at 275 nm but it was inconclusive with 335 nm excitation, however, it determined points of interest for spectra derivative studies. With the derivatives, it was possible to differentiate between Treatments 2 and 3 in the two wavelengths, focusing on specific wavelengths that can be decisive in the differentiation of adulterations. In relation to time resolved fluorescence spectroscopy, Treatment 1 demonstrated values of the mean emission lifetime higher over Treatments 2 and 3 at the two excitation wavelengths employed. The caffeine adulteration was performed in the Control 2 sample and a similar result was observed when compared to Control 1. In general, the application of stationary and time resolved fluorescence spectroscopy techniques allowed the characterization of the samples used in the study. In addition, it made possible the observation of differences between the control and adulterated samples, especially the one with caffeine added and excited at the wavelength 275 nm, with the help of mathematical tools. The results obtained here corroborate the fact that the techniques employed may be important in the detection of fraud in dairy products.

Master of Science / Department of Food Science / Karen A. Schmidt / Milk proteins are excellent sources of sulfur-containing amino acids methionine and cysteine, in particular whey proteins. Cysteine is synthesized from methionine by γ-cystathionase. However, cysteine has to be included in the diets of certain subpopulations due to diminished γ-cystathionase activity. Cysteine, a heat- liable amino acid, may lose bioavailability during thermal processing. The objective of this research was to enhance cysteine content in yogurt while maintaining its quality. First, yogurt mixes were formulated to a total solids content of 12.5% with nonfat dry milk (NDM) (N) or a combination of NDM (10%) and whey protein isolate (WPI) (2.5%) (W), and processed at 70°C (20 min) (70) or 90°C (7 min) (90). Yogurt was prepared and maintained at 4oC for 60 days. Three replications were performed and data were analyzed using SAS®. The W mixes had 65%, 32% and 190% more cysteine, true protein and whey protein contents respectively, compared to N mixes prior to processing. However in day 1 yogurt, the highest cysteine content (398.3 mg/L) was found in the W70 yogurt and its gel quality was comparable to the N90 yogurt except for firmness. During a 60 day storage period the W70 and N90 were similar in gel quality except for firmness. Secondly, a hedonic test was done on the W70 (HC) and N90 (LC) yogurts which had been reformulated to contain sugar and vanillin. One replication was performed and data were analyzed using SAS®. The LC and HC yogurts did not vary in liking of flavor (6.1), aftertaste (6.1) and overall acceptability (6.3) corresponding to the words of “like slightly” when compared. However, the appearance of the LC yogurt was liked more than the HC yogurt (6.7 vs. 6.1) whereas the thickness of HC yogurt was liked more than the LC yogurt (6.4 vs. 5.8). These results suggest that addition of WPI along with lower process treatment resulted in yogurt with enhanced cysteine; however, further studies may be needed to optimize the WPI addition to improve the visual characteristics of the yogurt for consumer acceptance.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Call number: LD2668 .T4 1978 C5269 / Master of Science

Surimi is a seafood product which is used to manufacture restructured products such as artificial crab and lobster. Surimi is produced from fish fillets by washing to remove sarcoplasmic proteins and increase the concentration of myofibrillar proteins, and mixing with cryoprotectants. A valuable attribute of surimi is its ability to form an elastic gel, the gel network being formed by the myofibrillar proteins of fish muscle. It is generally accepted that the quality of surimi gels is influenced by the activity of endogenous protease which acts on the myofibrillar proteins. The proteases in Pacific whiting surimi (Merluccius productus) are particularly problematic due to their high catalytic activity on muscle myosin. The addition of whey protein concentrate (WPC) to Pacific whiting surimi has been shown to enhance the gel strength of the corresponding products produced from this surimi. The mechanism through which WPC enhances the gel strength of Pacific whiting surimi has not been determined, but it has been suggested that WPC acts to inhibit surimi autoproteolysis. The objective of this study was to determine whether the incorporation of WPC into Pacific whiting surimi inhibits autoproteolysis and/or protects the myosin fraction from proteolytic degradation. The effect of supplementing surimi with WPC, beef plasma protein (BPP) and bovine serum albumin (BSA) on its apparent autoproteolysis activity was determined. Three WPC preparations were tested, WPC 34, 34% protein; WPC 80, 80% protein; and WPC 95, 95% protein. Each of the additives was incorporated at the 1, 2, 3 or 4% level. Proteolysis of surimi and supplemented surimi samples was allowed to occur at 55°C. Proteolytic reaction mixtures were terminated by the addition of trichloroacetic acid (TCA). Proteolytic activity was estimated by measuring the difference in TCA-soluble peptides present in reaction mixtures of paired (identical) samples, one having been incubated at 55°C while the paired sample was kept on ice. Peptides were quantified by the bicinchoninic acid, Lowry, dye-binding and trinitrobenzenesulfonic acid methods. Results based on the different peptide assays were compared in order to asses the reliance of results on specific assay methods. BPP was found to have the most inhibitory activity in the autoproteolysis assays, followed by the WPC preparations and then BSA. Autoproteolysis was completely inhibited by the incorporation of 1% BPP, 3% WPC 80 and 2% WPC 95. The extent of inhibition by the WPC preparations was related to their protein content, the higher the protein content the greater the extent of inhibition per unit weight added to surimi. BSA was not an inhibitor of autoproteolysis under the conditions used in this study. The relative extents of inhibition observed for the different additives were independent of the method used to quantify the soluble peptide products. Each of the additives was also tested for their ability to protect the myosin component of surimi from proteolytic degradation. These experiments were done as described above for the autoproteolysis assays with the exception that following the incubation period a portion of the sample, either surimi or a surimi/additive mixture, was completely solubilized in detergent solution, subjected to SDS-PAGE electrophoresis and visualized by protein staining. In these experiments the additives were incorporated at the 4% level. No apparent degradation of myosin could be detected over a 60 min reaction period for surimi samples that were supplemented with BPP, WPC 80 and WPC 95. In contrast, surimi samples incubated without additive clearly showed a loss of myosin after 15 min reaction period. Some myosin degradation was apparent following the 60 min incubation period for the WPC 34-supplemented surimi. A further experiment was conducted to determine the mechanism through which WPC protects myosin and inhibits autoproteolysis. In this experiment WPC 95 and BPP were separately incubated at 55°C with a crude fish protease preparation, i.e. the reaction mixture approximates that used in the autoproteolysis assays except that it contains no surimi. The results indicate that BPP and WPC 95 behave in a similar manner. However, the results were inconclusive with regard to explaining the additive's mechanism of action. Plausible mechanisms which are consistent with the results are discussed. / Graduation date: 1994

Whey proteins are mainly a group of small globular proteins. Their structures can be modified by physical, chemical and other means to improve their functionality. The objectives of this study were to investigate the effect of radiation on protein-protein interaction, microstructure, and microbiological properties of whey protein-water solutions. Whey protein isolate (WPI) solutions (27-36% protein) were treated with different dosages (10-35 KGy) of gamma radiation. The protein solutions were analyzed for viscosity, turbidity, soluble nitrogen, total plate count, and yeast and mold counts. The interactions between whey proteins were also analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and scanning electron microscopy (SEM). The viscosity of protein solution (27%, w/w) was increased from 2.19 for the control to 4.78 mPa*s for the sample treated at 25 KGy, respectively, and viscosity also increased during storage at 23°C. The soluble nitrogen (10%, w/w) was decreased from 100% to 54.7% for control and the sample treated at 35 KGy. The effects of gamma radiation and storage time on viscosity of whey protein solutions were significant (p

Uma das alternativas para a recuperação de energia de resíduos é o tratamento anaeróbio de efluentes com produção de metano e hidrogênio, utilizando-se reatores anaeróbios. Dentre as configurações possíveis de reatores, os descontínuos, como o ASBR e o AnSBBR, destacam-se ao permitem maior flexibilidade e estabilidade na operação, bem como maior controle dos efluentes do processo e menores tempos de partida. O objetivo deste trabalho foi avaliar a produção de metano a partir da digestão anaeróbia do soro em condição termofílica, avaliando também a adequação ambiental deste resíduo. O soro de queijo é o maior subproduto da indústria de laticínios, sendo gerado na proporção de 90% do volume de leite utilizado, com concentração de matéria orgânica entre 2 e 80g DQO.L-1, dependendo do processo produtivo. O reator foi operado de forma a permitir avaliar a influência da carga orgânica aplicada (limite de estabilidade), da estratégia de alimentação (tempo de enchimento batelada ou batelada alimentada), e da relação entre tempo de ciclo e concentração afluente (flexibilidade operacional). O reator operou a 55ºC, com tempo de ciclo de 8 horas e velocidade de agitação (100 rpm), sendo o volume alimentado por ciclo de 1,0 litro, com 1,5 litros de volume residual. O reator teve um período inicial de adaptação de 29 dias. Após este período, estudou-se a influência do aumento da carga orgânica pelo aumento da carga orgânica volumétrica aplicada, variando de 6,20 a 30,34 gDQO.L-1.d-1. A condição com carga orgânica volumétrica aplicada de 19,20 gDQO.L-1.d-1 apresentou os melhores resultados globais, alcançando eficiência de remoção de matéria orgânica na forma de DQO de 85,8% e 99,6% de carboidratos. O rendimento de metano gerado em função da matéria orgânica consumida foi de 13,07 mmolCH4.gDQO-1, sendo a produção de biogás de 6506 mL-CNTP.ciclo-1, com fração molar de metano equivalente a 73,7%. A produtividade molar de metano alcançada nesta condição foi de 324,0 molCH4.m-3.d-1 . Percebeu-se que as maiores cargas aplicadas acarretaram em perda de eficiência e instabilidade no reator. O modelo cinético de todas as condições foi ajustado corretamente, indicando que a rota de produção de metano preferencial foi a hidrogenotrófica em todo o período de estudo, porém, a via acetoclástica também foi presenciada em todas as condições. A mudança de estratégia de alimentação de batelada (2% do ciclo) para batelada alimentada (50% do ciclo) não melhorou os resultados de eficiência, estabilidade e produção de metano no reator. Realizou-se também a estimativa da recuperação energética estimando a produção de um pequeno, médio e grande produtor de queijo. A condição V apresentou os melhores resultados, possibilitando a recuperação de 826,10 MWh por dia tratando o volume de soro gerado numa indústria de grande porte (1.000.000 kg.mês-1) enquanto a melhor condição global (VIII) apresentou recuperação de 548,40 MWh. / One of the alternatives to recover energy from waste treatment is by the anaerobic treatment of effluents using discontinuous reactor configuration, such as ASBR and AnSBBR, aiming to produce methane and hydrogen. This reactors configuration allows greater flexibility and stability in the operation, a better controlled process, as well as shorter start-up. The objective of this project was to evaluate the methane production from the anaerobic digestion of cheese whey under thermophilic conditions. Cheese whey is the largest by-product of the dairy industry, it is generated in a proportion of 90% of the milk volume, its organic matter concentration can vary between 2 and 80 g COD.L-1 depending on the process. The evaluation of the environmental suitability of this residue was also analyzed. The reactor was operated to determinate the influence of the applied organic load (stability limit), feeding strategy (filling time - batch or fed-batch), and the relationship between cycle time and affluent concentration (operational flexibility). The reactor was operated at 55 ºC, with cycle time of 8 hours and 100 rpm of agitation speed. The volume fed per cycle was 1.0 liter with 1.5 liters of residual volume. The reactor had an initial adaptation period of 29 days. After this period, the influence of the organic load by increasing the applied volumetric organic load, ranging from 6.20 to 30.34 gDQO.L-1.d-1, was studied. The condition with volumetric organic load of 19.20 gDQO.L-1.d-1 presented the best overall results, reaching organic matter removal efficiency in the form of COD of 85.8 &#177; 2.0% and 99.6 &#177; 0.2% for carbohydrates. The yield of methane generated by organic matter consumed was 13.07 mmolCH4.gDQO-1, within biogas production of 6506 &#177; 185 mL-CNTP.cycle-1, with a methane molar fraction equivalent to 73.68 &#177; 0,43%. This condition molar productivity of methane achieved 324.0 molCH4.m-3.d-1. It was noticed that the higher organic loads applied lead to loss of efficiency and instability of the reactor. The kinetic model of all conditions was correctly adjusted, indicating that the preferred methane production route was hydrogenotrophic throughout the study period, but the acetoclastic pathway was also observed in all conditions. Changing from batch feeding strategy (2% cycle) to fed batch (50% cycle) did not improved the efficiency, stability and methane production results in the reactor. The energy recovery was also estimated by estimating the production of a small, medium and large cheese producer. Condition V presented the best results, allowing the recovery of 826.10 MW per day by treating the volume of cheese whey generated in a large industry (1.000.000 kg.month-1), while the best overall condition (VIII) recovered 548.40 MW.

Made available in DSpace on 2014-06-11T19:31:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-18Bitstream added on 2014-06-13T19:19:56Z : No. of bitstreams: 1 marques_dp_dr_arafcf.pdf: 1011746 bytes, checksum: 390ce3f3fe90df8ee33232cb2c868a7d (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação para o Desenvolvimento da UNESP (FUNDUNESP) / Os hidrolisados de proteínas do soro de queijo vêm sendo amplamente utilizados para diversos fins. Dependendo das enzimas utilizadas e meio de reação, podemos obter hidrolisados com diferentes características. O intuito do presente trabalho foi hidrolisar as proteínas do soro de queijo bovino de diferentes maneiras, variando-se a temperatura de reação e modo de adição das enzimas, a fim de se obter hidrolisados com diferentes graus de hidrólise para posterior aplicação em ensaios animais. Os hidrolisados escolhidos para aplicação nos ensaios biológicos foram obtidos pela ação das enzimas pepsina, tripsina, quimotripsina e carboxipeptidase a 50ºC. Dois hidrolisados diferentes foram preparados: um com maior quantidade de pequenos peptídeos (oligo, di e tripeptídeos) e outro com maior quantidade de aminoácidos livres. O soro sem hidrólise também foi utilizado como suplementação para um outro grupo de animais. A intenção foi testar os dois diferentes hidrolisados e o soro sem hidrólise como suplemento para ratos idosos, visando a minimização da sarcopenia. Diversos estudos apontam que fórmulas contendo oligopeptídeos, especialmente di- e tripeptídeos, possuem maior valor nutricional do que uma mistura equivalente de aminoácidos livres ou proteínas intactas. Tomando-se como base essa informação, delineou-se a pesquisa esperando-se que, o grupo suplementado com as proteínas parcialmente hidrolisadas obtivesse um melhor desempenho na minimização da sarcopenia. Todos os 3 grupos suplementados obtiveram aumento na massa muscular e óssea diferindo significativamente em relação ao controle (não suplementado) porem, o que apresentou efeitos mais positivos na minimização da sarcopenia foi realmente o grupo suplementado por proteínas parcialmente hidrolisadas. Paralelamente a esse estudo... / The cheese whey hydrolysates have been widely used for various purposes. Depending on the enzymes used and the reaction medium, we can obtain hydrolysates with different characteristics. The purpose of this study was to hydrolyze bovine cheese whey proteins in different ways, varying the temperature of reaction and enzyme addition, in order to obtain hydrolysates with different degrees of hydrolysis for application in animal tests. The hydrolysates chosen for application in biological assays were obtained by the action of enzymes pepsin, trypsin, chymotrypsin and carboxypeptidase at 50°C. Two different hydrolysates were prepared: one with a larger amount of small peptides (oligo-, di-and tripeptides) and another with larger amount of free amino acids. Serum without hydrolysis was also used as a supplement to another group of animals. The intention was to test the two different hydrolysates and whey without hydrolysis as a supplement to old age rats in order to minimize the sarcopenia. Several studies indicate that formulas containing oligopeptides, especially di-and tripeptides, have higher nutritional value than an equivalent mixture of free amino acids or intact proteins. Taking this information as a basis, the research was then outlined expecting that the group supplemented with partially hydrolyzed protein could obtain a better performance in reducing the sarcopenia. The all 3 supplemented groups showed increase in muscle mass and bone and differ significantly from control (not supplemented). However, the group who presented the most positive effects in reducing the sarcopenia was actually the group supplemented with partially hydrolyzed protein. In parallel with this study, in sandwich PhD, the attainment of immobilized pepsin and trypsin (derivatives) in solid support, stable was studied, for further application to obtain... (Complete abstract click electronic access below)

High-protein nutrition (HPN) bars (≥ 30% protein) have limited shelf life and become excessively hard during storage. Various mechanisms have been proposed to explain the hardening. The objectives of this research were to investigate the chemistry of HPN bar hardening and propose solutions for slowing it and improving bar texture. In phase 1, HPN bars were made containing 34% whey protein isolate (WPI) or milk protein concentrate (MPC) powder, along with either sorbitol syrup or glycerol, and vegetable shortening or cocoa butter. Substituting MPC for WPI made the bars brittle and crumbly. Using glycerol initially made bars softer but accelerated hardening. Cocoa butter increased bar hardness because of its higher solid to liquid content. Most water (~99%) in HPN bars made using sorbitol syrup is present as bound water, with ~0.9% as intermediate water and ~0.1% as bulk water. During storage bound water increased ~0.02 g/100 g of solids while intermediate water decreased, suggesting changes in state of water taking place at protein surfaces. During storage, there were changes in protein conformation indicated by an increase (~4°C) in heat denaturation temperature of β-lactoglobulin and α-lactalbumin and a 15 to 40% decrease in denaturation enthalpy. In phase 2, various bar formulations were tested involving different proportions of proteins, lactose, glycerol, and sorbitol syrup, as well as type of lipid component, and disulfide bonds inhibition. Decreases in bar hardening occurred when MPC and WPI and sorbitol syrup and glycerol were used in combination. In phase 3, HPN bars made with 38% protein powder as a 50:50 combinations of WPI and MPC and with 20% of sorbitol syrup substituted with glycerol, had good texture and minimal hardening during storage. Bar hardening was not caused by phase separation of protein and sorbitol, Maillard browning, or formation of inter-molecular disulfide bonds. Minimizing bar hardening requires prevention of entropy-induced protein aggregation by masking hydrophobic regions on protein surfaces and preventing formation of extended protein networks. It is proposed that preferential exclusion of cosolvents causes glycerol to be oriented at protein surfaces such that its carbon backbone masks hydrophobic regions thus avoiding a decrease in entropy of water molecules. (229 pages)