Impact of human milk pasteurization on the kinetics of peptide release during in vitro dynamic digestion at the preterm newborn stage

Holder pasteurization (62.5 degrees C, 30 min) of human milk denatures beneficial proteins. The present paper aimed to assess whether this can affect the kinetics of peptide release during digestion at the preterm stage. Raw (RHM) or pasteurized (PHM) human milk were digested in triplicates using an in vitro dynamic system. Mass spectrometry and multivariate statistics were conducted. Pre-proteolysis occurred mostly on beta-casein, for which cumulative peptide abundance was significantly greater in PHM over 28% of the hydrolysed sequence. Eight clusters resumed the kinetics of peptide release during digestion, which differed on seven clusters (69% of the 1134 peptides). Clusters associated to the heat-denaturated proteins, lactoferrin and bile salt-stimulated lipase, presented different kinetics of release during digestion, unlike that for beta-casein. Some bioactive peptides from beta-casein presented significant different abundances between PHM and RHM before digestion (1-18, 185-211) or in during intestinal digestion (154-160, 161-166). Further physiological consequences should be investigated.