Heat treatment affects gastric digestion kinetics but not amino acid bioavailability of milk proteins: a pig study.

Impact of heat treatment on digestion and absorption of milk proteins in vivo remains unclear. This study used Bama minipigs with duodenum-ileum double cannulas to investigate milk protein digestion and absorption under four heat treatments. During early gastric digestion (20 min), high-temperature treated milk (HTM) and ultra-high-temperature treated milk (UHTM) formed more fragmented protein curds. Additionally, β-lactoglobulin bands disappeared earlier than pasteurized milk (PM), indicating faster gastric digestion. Casein bands appeared sooner in HTM and UHTM than PM, indicating faster gastric emptying. Postprandial changes in plasma ghrelin and cholecystokinin kinetics confirmed faster gastric emptying for HTM and UHTM. However, no notable differences were observed in late gastric digestion (105 min) and plasma amino acid accumulation among different heat-treated milk. Collectively, this study illustrates that heat treatment can accelerate early gastric digestion of milk proteins without affecting overall digestion outcomes or amino acid bioavailability, providing guidance for advancing milk processing technologies.