Exploring protein digestion in water buffalo milk vs. holstein milk: An in vitro comparative study

Buffalo milk caseins coagulated faster into larger, rougher curds in gastric phase. • Buffalo milk showed slower and more sustained protein hydrolysis in gastric phase. • Fewer peptide species with lower sequence coverage were generated from buffalo milk. • Clot structure during gastric digestion was the key factor affecting hydrolysis. This study compared the digestion behavior and peptide profiles of water buffalo and Holstein skim milk using the standardized INFOGEST in vitro protocol. During the gastric phase, protein hydrolysis and amino acid release demonstrated that buffalo milk proteins underwent a slower but more sustained digestion process than those of Holstein milk. SDS–PAGE analysis further confirmed the slower rate of protein hydrolysis in buffalo milk. Particle size distribution and confocal microscopy revealed that buffalo milk coagulated more rapidly into larger and more wrinkled coagulates than Holstein milk, which likely reduced pepsin accessibility and contributed to the slower protein hydrolysis. LC–MS peptide profiling further showed that buffalo milk generated fewer peptide species with lower protein sequence coverage following gastric digestion. In the intestinal phase, proteins from both milks were rapidly degraded, and species differences in protein hydrolysis behavior and peptide profiles became less pronounced. Download: Download high-res image (165KB) Download: Download full-size image