Bioactive peptides and digestive characteristics of cow versus sheep/goat whey protein concentrates: Insights from in vitro gastrointestinal simulation

This study compared the digestion behavior and peptide release profiles of cow (CWPC) and sheep/goat (SWPC) whey protein concentrates under INFOGEST static in vitro gastrointestinal conditions. Although both protein sources exhibited similar degradation patterns, SWPC demonstrated 6.03% higher hydrolysis degree than CWPC. Gastrointestinal digestion significantly enhanced the antioxidant capacity of both protein digesta, with SWPC showing superior radical scavenging activities compared with CWPC. Peptidomic analysis identified a total of 4,434 peptides, with 2,095 and 1,521 peptides uniquely present in SWPC and CWPC digesta, respectively. These peptides were mainly derived from β-LG and α-LA. Notably, SWPC also released a greater quantity of peptides derived from lactoferrin and immunoglobulin-related proteins. The antioxidant peptide YVEELKPTPEGDL was 26.79% more abundant in SWPC digesta than in CWPC digesta (P < 0.05), whereas VGINYWLAHK and VDGKEDLIW were species-specific to SWPC and CWPC digesta, respectively. These findings suggest that SWPC has enhanced digestibility and antioxidant potential, and contribute to expanding the bioactive peptide repertoire from ruminant whey proteins. Overall, the study supports SWPC's value as a promising nutritional and functional protein source.