Effects of dry heating on the cleavage of casein and whey protein into peptides under simulated infant digestion

Glycation elicits diverse effects on the digestion of caseins and whey proteins in a goat protein model system (40 % casein,60 % whey proteins). Caseins generated longer peptides in the digesta of heated vs unheated samples. The further cleavage of casein peptides was hindered by dry heating, which might be induced by glycated modification. This reduced cleavage of casein peptides may also explain the decreased intensity of casein-derived bioactive peptides. Moreover, dry heating for 72 h significantly decreased the total intensity and number of whey protein-derived peptides. Whey protein-derived peptides in heated samples were shorter than those in unheated samples, and the cleavage sites of whey proteins were notably influenced. Dry heating increased the intensity of whey protein-derived bioactive peptides. These changes also affected the predicted bioactivity of peptides in the digesta, which may influence infant health. This study offers insights into the infant digestion of milk proteins into peptides.