In this study, nutritional data on the four major kinds of infant products for special medical purposes produced in China and some other countries were collected and compared for differences in the three calorigenic nutrients, vitamins, minerals, and mandatory or optional nutrients. Moreover, principal component analysis (PCA) was carried out on these data. The results showed that the domestic brands of amino acid-based or hypoallergenic infant formula were significantly richer in fat, vitamin K, pantothenic acid, and taurine than the imported brands (P < 0.05), but had a significantly lower content of folic acid (P < 0.05). The contents of fat, manganese, taurine, and carnitine in the domestic brands of partially hydrolyzed milk infant formula were significantly higher than those in the imported brands (P < 0.05). The contents of iron, vitamin D, and vitamin B2 in the domestic brands of lactose-free or low-lactose infant formula were significantly higher than those in the imported brands (P < 0.05). Notwithstanding, no significant differences in any of the tested nutrients were observed between the domestic and imported brands of infant formula for low birth weight infants and preterm infants. The results of PCA showed that the contents of manganese, VB5 and VB3 made the greatest contribution to the nutritional difference between the domestic and imported brands of amino acid-based or hypoallergenic infant formula, the contents of VB6, VB2, VB5 and VB3 made the greatest contribution to the nutritional difference between the domestic and imported brands of partially hydrolyzed milk infant formula, while the contents of VB5 and VB3 made the greatest contribution to the nutritional difference between the domestic and imported brands of lactose-free or low-lactose infant formula and of infant formula for low birth weight infants and preterm infants.

The physical properties of the raw materials used to produce foods for special medical purposes intended for infants need to be considered in the process of formulation design. In order to facilitate the formulation design and rapidly determine the amount of the major raw materials with complex chemical composition used to produce foods for special medical purposes intended for infants, some physical properties of these materials and auxiliary materials such as granularity, tap density and angle of repose were investigated. Moreover, the granularity, tap density, angle of repose and particle size distribution of commercial produced products from the formulations developed in this study were also analyzed. The results showed that all the products had identical physical properties, indicating these formulations can meet the requirements of commercial applications without modification.

According to the characteristics of macronutrients in breast milk, infant and follow-up formula milk powder was developed suitable for Chinese infants and babies by adjusting the contents of protein, fat and carbohydrate in milk powder and the rationality of this design was evaluated using in vitro digestibility tests. The results showed the content of each macronutrient in the formula milk powder was in accord with the requirements of Chinese and international standards and could meet macronutrient needs of infants and babies. The total in vitro digestibility of proteins approximately was 88% in the formula milk powder, which was higher than that of commercial infant formula and goat milk powder, and it was increased to 95% by increasing enzyme levels. Therefore, the formula milk powder had a reasonable nutritional profile and could be easily be digested and absorbed by infants.