Gastric clot formation and digestion of milk proteins in static in vitro infant gastric digestion models representing different ages

Gastric digestion conditions change during infancy from newborn towards more adult digestion conditions, which can change gastric digestion kinetics. However, how these changes in gastric digestion conditions during infancy affect milk protein digestion has not been investigated. Therefore, we aimed to investigate milk protein digestion with static in vitro gastric digestion models representing one-, three- and six-month-old infants. With increasing age, gastric clots and soluble proteins were digested more extensively, which may partly be attributed to the looser gastric clot structure. Larger differences with increasing age were found for heated than unheated milk proteins, which might be caused by the presence of denatured whey proteins. Taken together, these findings show that gastric milk protein digestion increases during infancy. These in vitro gastric digestion models could be used to study how milk protein digestion changes with infant age, which may aid in developing infant formulas for different age stages.