LAUSR

BACKGROUND Using transglutaminase (TGase) is a new method to improve protein properties in order to promote protein glycosylation. This article mainly studies soy protein isolate (SPI) and glucosamine (G) to improve the freeze-thaw stability of emulsion under the action of TGase. The degree of glycosylation was studied by the content of free amino groups and the degree of conjugation. The optimal conditions for preparing SPI-G conjugate were determined by response surface optimization model based on single-factor experiments using the creaming index of the emulsion after the first freeze-thaw cycle as the response value. RESULTS The results showed that the emulsion had the lowest creaming index under the conditions of protein concentration was 20 g L-1 , mass ratio of SPI/G was 5:3 (w/w), enzyme addition amount was 10 U g-1 , and reaction time was 2 h. The optimized modified product was measured for the creaming index after the first freeze-thaw cycle. It was found that the creaming index of the modified product soy protein isolate-glucosamine (SPI-G) after the first freeze-thaw cycle was 9.02%, which was less than and close to the optimized model predicted value. The creaming index and optical microscopy results after three freeze-thaw cycles confirmed that the freeze-thaw stability of the SPI-G samples was significantly enhanced after optimization of the response surface model. CONCLUSION It showed that glycosylation promoted by transglutaminase could improve the freeze-thaw stability of SPI emulsion, thereby broadening the application of SPI in food. This article is protected by copyright. All rights reserved.