Simulated dynamic digestion reveals different peptide releases from human milk processed by means of holder or high temperature-short time pasteurization

High Temperature-Short Time (HTST) pasteurization was proposed as an alternative to Holder pasteurization (HOP) to increase the retention of specific human milk (HM) bioactive proteins. The present study explored whether HTST and HOP differently affect peptide release during simulated preterm infant gastrointestinal digestion. Raw (RHM), HOP- and HTST- pasteurized HM were digested using an in vitro dynamic system, and the identified peptides were analyzed by mass spectrometry and multivariate statistics. Before digestion, 158 peptides were identified in either RHM, HTST- or HOP- HM, mostly (84.4%) originating from β-casein (CASB). During gastric digestion, HOP-HM presented a greater number and more abundant specific CASB peptides. A delayed release of peptides was observed in RHM during the intestinal phase, with respect to both pasteurized HM. Although limited to gastric digestion, the HM peptidomic profile differed according to the pasteurization type, and the pattern of the HTST peptides showed a greater similarity with RHM.