Preparation and characterization of the soybean protein isolate - chitosan oligosaccharide Maillard reaction products via wet-heating

Chitosan oligosaccharide (COS) is a cationic saccharide and one of the most abundant natural resources, which could be a promising agent to achieve the purpose of modification for proteins. In this study, soybean protein isolate (SPI) was selected as a model protein and its interaction with COS via Maillard reaction under wet-heating conditions was evaluated compared with glucose. Although a milder reaction of SPI with COS than with glucose was observed from physicochemical property testing, the conjugation with COS via wet-heating significantly improved the solubility and emulsification ability of SPI. Structural analysis suggested that covalently interacted with COS affected the secondary structure of SPI and an increase in random coil content was observed. In summary, COS showed good potential in the modification of proteins by Maillard reaction under wet-heating. This study might provide new ideas for the modification of proteins and lay a theoretical foundation for the application of COS. Practical applications As a natural and non-toxic approach to improve technological functionalities of proteins, the conjugation with polysaccharide via Maillard reaction under wet-heating can serve as economical source of emulsifier as well as good encapsulating matrix. This study might provide new ideas for the modification of proteins and lay a theoretical foundation for the application of COS.