Digestion patterns of proteins in pasteurized and ultra-high temperature milk using in vitro gastric models of adult and elderly

The objective of the current study was to investigate gastric digestibility of milk proteins in an in vitro model of the elderly considering their altered physiological capabilities reported in vivo. Commercial pasteurized and ultra-high temperature (UHT) milks were exposed to in vitro models of the adult and elderly and their protein degradation patterns were investigated during digestion using liquid chromatography-mass spectrometry (LC-MS). Our results showed significant differences in the gastric digestion of milk proteins between the adult and elderly models in pasteurized and UHT milks. For the pasteurized milk, the relative mean abundance of larger peptides (>30 amino acids) was 2.5 fold higher after 60 min in the elderly model than the adult model. The digestion of caseins in the UHT milk in the elderly model occurred with a lower rate under the first 30 min of hydrolysis. Similarly, immunoglobulins showed at least 3 times more effective gastric digestion in the pasteurized milk.