Characterization of structure, physicochemical properties, and hypoglycemic activity of goat milk whey protein hydrolysate processed with different proteases

Abstract

Goat milk whey protein (WP) hydrolyses have attracted much attention due to their variety of biological activities. In this study, the potential hypoglycemic activity of WP was predicted by in silico analysis, and the types of proteases with stronger hypoglycemic activity were selected based on these results. The impact of enzymatic hydrolysis by seven types of proteases (alcalase, neutrase, trypsin, bromelain, pepsin, papain, and proteinase K) on the degree of hydrolysis (DH) of WP was evaluated. Meanwhile, the physicochemical, structure, and emulsifying properties of WP and its hydrolysates were also investigated. The hypoglycemic activities were verified by the inhibition of dipeptidyl peptidase IV (DPP-IV), α-glucosidase, and α-amylase activity. Results demonstrated alcalase hydrolysates exhibited the highest DH value (35.54 ± 0.53%) and lower molecular weight. The average particle size, zeta-potential, and emulsifying properties of the seven protease hydrolysates were significantly decreased (P < 0.05) compared with WP. Furthermore, the intrinsic fluorescence intensity of the seven protein hydrolysates red-shifted. In addition, the hydrolysate activity of alcalase and papain showed higher inhibition of α-glucosidase, α-amylase activity, and DPP-IV. These results suggest that WP hydrolysate could be a natural hypoglycemic food supplement.