Orientador: Jaime Amaya-Farfán

Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos

Resumo: As proteinas do soro de leite possuem alto valor nutritivo, sendo, portanto, extensamente estudadas em diversas areas do saber. A equipe do Laboratorio de Fontes Proteicas vem estudando a associacao entre o consumo do hidrolisado de proteina do soro de leite e seus efeitos biologicos e...

Resumo: As proteinas do soro de leite possuem alto valor nutritivo, sendo, portanto, extensamente estudadas em diversas areas do saber. A equipe do Laboratorio de Fontes Proteicas vem estudando a associacao entre o consumo do hidrolisado de proteina do soro de leite e seus efeitos biologicos e nutricionais, em varios niveis de atividade fisica. Seu consumo tem sido associada a diminuicao do estresse metabolico, reducao nos niveis de lactato, aumento das reservas de glicogenio muscular, maior estabilidade da albumina serica e melhora nos tempos de exaustao do animal treinado. Este trabalho teve por objetivo avaliar o efeito do consumo do hidrolisado de soro de leite no estado metabolico redox do rato e na utilizacao de lipideos pelo organismo como fonte de energia durante a atividade fisica. Ratos Wistar machos foram divididos em 3 grupos de dieta: Padrao (AIN 93-G, dieta elaborada com caseina), Controle (AIN 93-G, elaborada com concentrado de proteinas do soro de leite) e Experimental (AIN 93-G, elaborada com hidrolisado de proteinas do soro de leite). Cada dieta foi subdividida em 4 grupos (n = 7): sedentarios, sedentarios-exaustos, treinados e treinados-exaustos. O hidrolisado apresentou maior poder antioxidante in vitro, do que o concentrado e tres fracoes do soro, ?-lactalbumina, ?-lactoglobulina e albumina serica bovina. O consumo das proteinas do soro de leite, hidrolisadas ou nao, aumentou a concentracao de triptofano no sangue e de BCAAs livres no musculo, alem de 10 outros aminoacidos analisados. Porem, reduziu o nivel de alanina aminotransferase serica. A enzima tambem teve sua concentracao reduzida pelo treinamento fisico enquanto que a exaustao aumentou-a. Contrariamente, o exercicio continuo aumentou os niveis de acidos graxos livres sericos, ao passo que a exaustao os diminuiu. Ambas as variaveis, por sua vez, elevaram nao somente a temperatura muscular, mas tambem o nivel de 15 aminoacidos musculares livres e a concentracao de triacilglicerois sericos. O treinamento possibilitou que os animais treinado-exaustos apresentassem tempos ate a exaustao mais longos que os sedentarios-exaustos. A exaustao tambem aumentou a concentracao de nove aminoacidos sericos (dentre eles BCAAs, Ala e Gln). O treinamento, bem como a exaustao e a dieta não interferiram na expressao dos genes PPAR a, PPAR d, PGC 1a, CPT 1ß e miostatina no musculo. Nao foram constatadas alteracoes no consumo, peso do tecido adiposo, lactato sanguineo, glutationa reduzida, alem dos parametros sericos: creatinina, aspartato aminotransferase, albumina, corticosterona e acido urico. Os resultados deste trabalho sugerem haver poucas diferencas entre as dietas formuladas com proteinas do soro de leite. Porem, eles tambem sugerem que o nivel de atividade a ser empregado em ensaios biologicos deva ser criteriosamente definido

Abstract: There is extensive research on whey proteins because of its particularly high level of nutritive value. The Protein Sources Laboratory team has studied the relationship between the intake of hydrolyzed whey protein and its biological and nutritional effects at several levels of physical...

Abstract: There is extensive research on whey proteins because of its particularly high level of nutritive value. The Protein Sources Laboratory team has studied the relationship between the intake of hydrolyzed whey protein and its biological and nutritional effects at several levels of physical exercise. It has been observed that time to exhaustion is improved, serum lactate levels and metabolic stress are reduced, muscle glycogen stores are increased, and serum albumin levels are preserved. This work aimed at assessing the effects of consuming the hydrolyzed whey proteins on the metabolic redox state and the utilization of lipids as energy during physical exercise. Male Wistar rats consumed 3 diets: Experimental (AIN 93-G, prepared with hydrolyzed whey protein), Control (AIN 93-G, prepared with concentrate whey protein) and Standard (AIN 93-G). Each diet was further grouped into 4 cases (n = 7): sedentary, exhausted-sedentary trained and exhausted-trained. The hydrolyzed whey protein presented a greater antioxidant effect in vitro, than the concentrate, and its main protein components. Both the hydrolyzed and unhydrolyzed whey protein increased the tryptophan blood concentration as well as the free BCAA muscle concentration, in addition to ten other amino acids. Moreover, it reduced the serum alanine aminotransferase level. Physical training also reduced its concentration, whereas exhaustion increased it. On the other hand, continuous physical exercise increased free fatty acids levels, whereas exhaustion decreased it. Moreover, both variables increased not only the muscle temperature but also 15 muscle amino acids levels as well as the triacylglycerols levels. Training led to longer time to exhaustion of the trained-exhausted than to sedentaryexhausted. Exhaustion also increased the concentration of nine serum amino acids (among them BCAAs, Ala e Gln). Both training and exhaustion, and diet had no affect on the gene expression of PPAR a, PPAR d, PGC 1a, CPT 1ß and myostatin in the muscle. No effect was observed for food intake, adipose tissue mass, blood lactate, reduced glutathione as well as serum parameters: creatinine, aspartate aminotransferase, albumin, corticosterone, uric acid. These findings indicated that there are few differences between the whey-protein based diets. However, they do point out that some level of activity should also be taken into account during the biological experiments