Abstract: Being rich in high-quality proteins, minerals and microelements, organically grown soybean flour is a major raw material for the production of non-dairy formulae. In this study, a soybean-based infant formula was developed using organically grown soybean flour and soybean protein isolate (SPI) as the protein sources. The aims of this study were to investigate the chemical composition, amino acid composition, microstructure, osmotic pressure, and protein efficiency ratio (PER) of the infant formula. The results showed that the nutritional composition of the infant formula powder was in accordance with the National Food Safety Standard for Infant Formula (GB 10765-2021). The essential amino acid composition was better than that of commercial soy-based infant formula. The amino acid score (AAS) was more balanced. In addition, the infant formula, richer in essential amino acids such as histidine, could meet the nutritional requirements of infants and may be used as an alternative to breast milk. Transmission electron microscopic (TEM) photographs showed that the granule size distribution of the formula was more uniform compared with commercial infant formula. The osmotic pressure of the formula was (281.00 ± 1.20) (mOsm/kg H2O) which is suitable for infants. The percentage body mass gain and PER of rats fed the formula were higher than those of rats fed casein suggesting that the formula could promote the growth and development of rats owing to its high nutritional value. These findings may provide basic data for the development of soybean-based infant formula.

Key words: soybean-based infant formula; organically grown soybeans; soybean protein isolate; physicochemical properties; protein efficiency ratio