How to adjust α-lactalbumin and β-casein ratio in milk protein formula to give a similar digestion pattern to human milk?

Protein composition can affect the digestion properties. The present study aims to investigate the digestion properties of milk protein formulas (MPFs) with different compositions. An in vitro infant digestion model was used to compare the digestive behavior of human milk (HM) and four bovine MPFs based on a whey protein-to-casein ratio of 60:40: one with ordinary ratios (i.e., OMPF) of α-lactalbumin (α-La) and β-casein (β-CN) and the other three with fortified ratios (low, medium and high, i.e., LMPF, MMPF and HMPF) of α-La and β-CN. LMPF and MMPF exhibited a higher degree of protein hydrolysis, contents of free amino acids and essential amino acids bioaccessibility which were much closer to HM than other MPFs. Similar to HM, the peptides derived from β-CN were the dominant ones in all the MPFs. In sum, MPFs with the ratio of α-La and β-CN close to HM gave similar digestion patterns to human milk, especially in intestinal digestion. This study provides guidance on the improvement of infant formula to be more similar to human milk from both protein composition and protein digestion perspectives.