As an ideal model for human intestinal research, the pig, whose intestinal anatomy, enzyme system development and nutritional metabolism characteristics are very similar to those of infants and young children, has been widely used in recent years to evaluate infant formula and milk protein function research. To address the lack of basic amino acid data of the Asian population and the unclear mechanism of protein digestion and absorption in the precise design of infant formula, Yin Yulong's team from the Institute of Subtropical Agricultural Ecology, Chinese Academy of Sciences, in collaboration with Inner Mongolia Dairy Research Institute, Xiangya School of Public Health of Central South University and Massey University of New Zealand, has conducted a series of studies on the determination of amino acids in breast milk of Asian women and the nutritional evaluation of milk proteins for infants. The results were published in The Journal of Nutrition (2023) and Journal of Agricultural and Food Chemistry (2025).

In one of the studies, the research team collected milk samples from 75 lactating women in China, accurately determined the amino acid content of the milk using multi-temporal proteolytic digestion combined with a non-linear modelling approach, and evaluated the true ileal digestibility using a piglet model. The results showed that glutamic acid, aspartic acid and leucine were the most abundant amino acids in human milk. Among the 18 amino acids, the digestibility of cystine and tyrosine was low. This study is the first to systematically establish the "breast milk amino acid profile of the Asian female population", which provides accurate data for optimizing protein quality and the proportion of essential amino acids in infant formula.

Another study focused on the effect of the ratio of α-lactalbumin (α-La) to β-casein (β-CN) in infant formulae on the efficiency of protein digestion and absorption and the development of infant gut structure. Researchers co

Contact: Xia Xiong

E-mail: xx@isa.ac.cn

Graphical Abstract (Image by Xia Xiong).