Prospecção e avaliação das atividades biológicas dos peptídeos obtidos a partir da proteólise do caseinato de ruminantes

Abstract

Bioactive peptides, mainly derived from the enzymatic hydrolysis of milk casein, antioxidants, antihypertensives, antidiabetics, ability to isolate metals and antimicrobial capacity. The milk, in general, presents in its composition casein an important source of protein fragments with expressive biological activity. Thus, the objective was to investigate the biological potential of peptides derived from bovine casein, buffalo and caprine submitted to the proteolytic action of bromelain, papain, neutrase and trypsin in order to select the hydrolyzate with the highest antioxidant potential; fractionating the selected hydrolyzate and evaluating the antioxidant and antidiabetic potential of the fractions. It was possible to observe significant differences (p <0.05) between caseinates presenting a minimum degree of hydrolysis of 2% (bovine) and maximum of 85% (buffalo). In relation to the antioxidant activities, it was observed a distinct behavior of the caseinates against the different enzymatic treatments over 480 minutes. Hydrolysates presented a potential for sequestration of hydroxyl radicals (between 0 and 100%), superoxide (greater than 80%), ABTS (greater than 85%), DPPH (between 20 and 95%) and chelate iron (between 10 and 100%) and copper (between 14 and 80%); Regarding the antioxidant activities of the fractions from the selected species (buffalo), the hydroxyl and DPPH tests had a higher elimination potential in fractions of 3-10 kDa and <3 kDa, varying according to the enzymatic specificity, whereas the higher ABTS radical sequestration potential was observed in the fraction containing the total hydrolyzate. For the chelating activity of iron, it was observed more than 70% chelation in all the fractions, emphasizing the fractions <3 kDa. For copper chelation, values higher than 60% were observed in fractions >10 kDa. The anti-diabetic activity had a variable potential in relation to the α-glycosidase inhibition between the fractions, whereas α-amylase was better inhibited by the fraction <3 kDa. Antibacterial activity was observed between 3.28 and 100% inhibition against the microorganisms tested, the fraction <3 kDa showed a greater inhibitory potential. The antihypertensive activity of the fractions remained between 39.35 and 89.58%, especially the peptide fraction H3. The proteases used in the hydrolysis of caseinates presented the potential to obtain hydrolysates with the three evaluated species of antioxidant protein fragments. In addition, they showed the capacity to produce fractions of hydrolysates with antioxidant potential, antidiabetic, antihypertensive and antimicrobial, therefore the ultrafiltration method proved effective in the fractionation of peptides with different molar masses. In this way, the total hydrolysates of the three species as well as the fractions of the selected species present potent antioxidant activity, which proves potential food application as a functional food, nutraceutical or as a natural food additive.