In vitro digestion of novel milk protein ingredients for use in infant formulas: Research on biological functions

Rather than using lengthy clinical studies, in vitro digestion of milk proteins by human neonatal gastric juice at pH values representing those in early neonatal life was investigated. Human milk proteins resisting digestion were immunoglobulins, secretory IgA, α S1-casein, secretory component, osteopontin and MUC-1. Bovine milk proteins resisting digestion at pH 4.0 were immunoglobulins, BSA, caseins, lactadherin, osteopontin, EPV20 and proteose peptone component 3 (PP3). Some proteins were rapidly digested e.g. CGMP. In vitro digestion provides rapid information regarding the susceptibility of proteins to gastric proteases and is a convenient alternative to clinical studies.