Comparative in vitro intestinal transport and bioactivity of peptides from wet- and dry-heated goat milk proteins after simulated infant digestion

This study investigated the digestion of proteins (12 mg/mL) in goat skimmed milk with casein-to-whey protein ratios of 80:20 and 40:60. The effects of dry and wet heating on peptide formation and peptides transport were studied in vitro. Peptide transport across the Caco-2 cell monolayer was largely determined by the peptide composition in the digesta. Some peptides were further cleaved during transport across the Caco-2 monolayer. Transport was associated with glycation, peptide length, and hydrophobicity; fewer peptides with advanced glycation were transported across the Caco-2 cell monolayer. Basolateral peptides were relatively shorter and more hydrophilic than digesta peptides, probably due to further proteolysis by Caco-2 cell-derived enzymes. Protein composition and heat treatment influenced the presence of bioactive peptides and linear epitopes in the basolateral compartment. This study highlights the importance of the casein:whey ratio in goat milk based infant formula and indicates dry heating could affect its nutritional quality.