Análise do potencial antioxidante de hidrolisados do soro de leite caprino da raça Toggenburg

Abstract

Goat milk has been studied for its potential to promote health, being a promising source of bioactive peptides. In the human body, excessive production of reactive oxygen species causes oxidative stress, which is associated with aging and degenerative diseases. Bioactive peptides obtained from goat whey have multifunctional properties, modulating biological responses, such as antioxidant, reducing oxidative stress. Thus, the present work aims to verify the antioxidant capacity of Toggenburg goat whey hydrolysates, obtained with different enzymes and reaction times. Whey was obtained from isoelectric precipitation of mature goat milk. Soluble proteins were analyzed using the Bradford method and solubility was verified at different pH. Subsequently, the sample was subjected to enzymatic hydrolysis with pepsin or trypsin for 30 min or 60 min and the degree of hydrolysis was analyzed by the orthophthaldehyde method and the TCA-soluble nitrogen method. Furthermore, the concentration of free amino acids in whey and hydrolysates was verified and the protein profile was determined by SDS-PAGE. The analysis of antioxidant activity occurred using the ABTS and DPPH radical capture method, through the total reduction power and the induction of oxidative stress in human erythrocytes. Thus, the whey protein concentrate obtained had a soluble protein content of 46% and better solubility at pH 7. The enzymatic hydrolysis of the whey protein concentrate generated four hydrolysates, with a better degree of hydrolysis in the samples. with a reaction time of 60 min for both enzymes. In SDS-PAGE, it was possible to identify whey proteins, such as immunoglobulins (149 kDa), β-lactoglobulin (13 kDa) and α-lactalbumin (9 kDa), estimate their molecular weight and verify hydrolysis. Furthermore, treating the sample with pepsin for 60 min was more effective in releasing free amino acids and in antioxidant activity by capturing ABTS and DPPH radicals. The samples presented oxidizing action on hemoglobin considered high, however, regarding the antioxidant action on hemoglobin, all hydrolysates significantly inhibited the oxidizing agent phenylhydrazine. In this way, Toggenburg goat whey was able to generate bioactive peptides with significant antioxidant activity, which could be considered for application in the food and pharmaceutical industries.