Characterization of the Improved Biological Activity, Functionality, and Emulsion Stability in Soybean Meal Hydrolysates–Proanthocyanidins Conjugates Prepared by Alkali Treatment

Abstract

This study investigated the structure, biological activity, and emulsion stability of soybean meal hydrolysates (SMHs) after covalent conjugation with different concentrations of proanthocyanidin (PC). SDS-PAGE results showed that an increase in PC concentration resulted in the development of more high-molecular-weight polymers (40 kDa) the SMHs–PC conjugates. Structural analysis indicated unfolding and disordered structure formation with increasing PC concentration, which increased the antioxidant activity and emulsification of the SMHs. When the PC concentration was 3.0 mg/mL, the SMHs–PC conjugates showed the highest antioxidant activity (ABTS •+ and DPPH radical scavenging capacities of 89.08 ± 0.47 and 40.90 ± 1.53%, respectively) and emulsification activity (79.13 ± 2.80 m2/g), which may be attributed to protein unfolding. Moreover, the SMHs–PC emulsion showed the smallest particle size and highest viscosity when the PC concentration was 2.0 mg/mL, and has potential applications as an emulsifier with high biological activity in food.

Keywords: soybean meal hydrolysates, proanthocyanidins, biological activity, functionality, emulsion stability