Properties and Antioxidant Activity of Ultrafiltered Soybean Peptides Using Enzymatic Hydrolysis

Abstract

This study aimed to analyze the physicochemical properties and antioxidant activity of low molecular weight peptides produced by the enzymatic hydrolysis of soy protein. Soy protein isolate was treated with 0.1% and 0.3% protease (w/w), and then each hydrolyzate was ultrafiltered using 3 kDa and 10 kDa membranes. The pH value of the hydrolyzate was significantly lower at higher enzyme concentrations, but there was no difference according to the molecular weight cut-off. The salinity did not show a significant variation in any of the treatment groups, and the total dissolved solids were the highest at 0.3% in the 10 kDa sample. The enzyme concentration of hydrolyzate affects its color more significantly than the molecular weight cut-off. The DPPH and ABTS radical scavenging activities were the highest in the sample, with 0.3% enzyme concentration and 10 kDa cut-off. Peptides under 3 kDa also had a significant effect on the antioxidant activity. The principal component analysis of the electronic tongue (e-tongue) data significantly distinguished 3 kDa and 10 kDa fractions with a 0.1% enzyme concentration. Based on these results, using the 0.3% enzyme for the enzymatic hydrolysis of soy protein can be an efficient method to produce seasoning materials that have functional properties from plant protein.

Preparation and identification of an antioxidant peptide from wheat embryo albumin and characterization of its Maillard reaction products

“…In recent years, polypeptides extracted from a wide variety of food proteins by enzymatic method have become one of the new sources of antioxidants largely due to the fact that they possess beneficial functional properties and safety (Wong et al, 2020). Specifically, studies have reported extraction of antioxidative peptides from a wide variety of protein sources, including Vicia faba (Kuerban et al, 2020), mung bean (Sonklin et al, 2021), soybean (Oh et al, 2021), corn (Hu et al, 2020), and cottonseed (Wang et al, 2021). Wheat germ, a byproduct of flour processing, has a protein content of up to 30%.…”