Preparation of casein non-phosphopeptide-soybean polypeptide complex, its structure and emulsifying properties' evaluation

摘要

The objective of the present work was to improve emulsifying properties and methionine content of soybean protein. Chymotrypsin was used as a reaction catalyst to form a new protein complex from soybean polypeptide and casein non-phosphopeptide. The degrees of hydrolysis and hydrophobicity were measured and their relationship with physicochemical properties such as emulsifiability was studied. Instrumental or chemical analyses were also performed to determine the amino acid content and tissue changes of casein non-phosphopeptide-soybean polypeptide complex (CNPSPC).The results show that casein non-phosphopeptides and soybean polypeptides can aggregate together to generate new chemical bonds. The emulsifying activity and emulsion stability of CNPSPC were higher than those of soybean polypeptides. Microstructure analysis showed many network pores distributed in casein non-phosphopeptide-soybean polypeptide complex sample. In addition, analysis of amino acid content in CPSPC showed that methionine accounted for 1.8% of all amino acids (w:w), and it is 216.1% more than soy polypeptides.