Peptide release, radical scavenging capacity, and antioxidant responses in intestinal cells are determined by soybean variety and gastrointestinal digestion under simulated conditions

Abstract

This research evaluated the association between the different protein and peptide composition of seven soybean varieties and their radical scavenging and antioxidant properties throughout simulated gastrointestinal digestion. Glycinin and β-conglycinin were the primary and more varying proteins among soybean varieties. Protein composition determined the degree of hydrolysis, which negatively correlated with glycinin concentration (r = −0.911). Peptide sequencing evidenced the diversity of released peptides among soybean varieties. Although potentially less absorbable in intestinal cells, bigger peptides exhibited a stronger in silico binding affinity with Keap1 (r = 0.806). Digested soybean radical scavenging and antioxidant properties were positively associated with protein (r = 0.900) and glycinin (r = 0.824) concentration. Soybean digested fractions reduced oxidative stress (21–118%) and cell death in intestinal epithelial cells by activating (1.2–3.6-fold) Nrf2-dependent antioxidant responses. Differences in the protein and peptide composition influence soybean health-promoting properties and will guide the production of healthier soybean-based products.