Preparation of Hypoallergenic Soy Protein Isolate Hydrolysates with Different Degrees of Hydrolysis and Their Physiological Activities

Abstract

This study employed four proteinases (Alcalase, Dispase, Flavourzyme, and compound proteinase) for the enzymatic hydrolysis of soy protein isolate. The hydrolysates' antioxidant activity, α-glucosidase inhibitory activity and linear epitopes of antigens were evaluated through the analysis of the structural properties of the hydrolysates. The objective is to reduce allergenicity and to explore the link between the structure and physiological activity of SPI hydrolysates. The findings indicated that the hydrolysis by the proteinase disrupted the hydrogen bonding and hydrophobic structure of soy protein isolate. Concomitantly, the α-helix and β-folding structure content of soy protein isolate diminished, suggesting a reduction in the ordered structure of SPI, and SPI hydrolysates showed significantly enhanced antioxidant activity. After enzymatic hydrolysis, the inhibitory activity of α-glucosidase was significantly increased from 4.53% (SPI) to 38.01% (SPH- A); the major antigenic residues β-conglycinin was reduced by 25% and glycinin was reduced by 17.23% by hydrolysis with Alcalase.

Keywords: soy protein isolate, Proteinases, Physiological activities