Effects of transglutaminase glycosylated soy protein isolate on its structure and interfacial properties

Abstract BACKGROUNDS The structural and interfacial properties of soybean protein isolate (SPI) after glycosylation by the transglutaminase method were studied. It is hoped that preliminary explorations will find a new food ingredient and broader application of SPI in the food industry. RESULTS The contents of free amino proves that transglutaminase can insert glucosamine into SPI through its transamination, and realize the enzymatic glycosylated SPI. The results of structure properties showed that a decrease in the content of the α‐helical structure indicates that the rigid structure of the protein is opened and the flexibility is increased. The blue shift of the maximum fluorescence intensity of soy protein isolate‐glucosamine with transglutaminase (SPI‐G) indicates the formation of a new substance; scanning electron microscopy shows that the SPI‐G powder can be seen at a magnification of 2000×, and the protein structure becomes soft. The results of interfacial properties found that enzymatic protein glycosylation exposes the internal hydrophobic groups of SPI, resulting in increased surface hydrophobicity, increased emulsification and emulsification stability, and reduced surface tension. CONCLUSION It shows that SPI‐G effectively improves the interfacial properties of SPI, providing a theoretical basis for the application of enzymatic glycosylation of SPI in the food industry. © 2021 Society of Chemical Industry