Glycinin-carbohydrate conjugates: Preparation, characterization, and application in processing of whole soybean curd

Abstract

Glycinin-carbohydrate conjugate prepared with glucose, fructose, or dextran using a dry-heating method was applied to improve the processing quality and textural properties of whole soybean curd (WSC). The optimal parameters for preparing glycinin-carbohydrate conjugates were obtained using single factor experiment and response surface optimization. Compared to native glycinin, all glycinin-carbohydrate conjugates prepared under the optimized parameters exhibited improved solubility and emulsifying properties, especially the glycinin-dextran conjugate. Yield, hardness, and gel strength of WSC were significantly elevated when glycinin-carbohydrate conjugates were applied as a part of raw material. For instance, when 15% glycinin-dextran conjugate was added, the yield, hardness, and gel strength of WSC were increased by 32.70%, 52.46%, and 32.72% compared to those of the WSC made only from soybean flour, respectively. Meanwhile, glycinin-carbohydrate conjugates modified the microstructure of WSC to be denser and more homogeneous, which was more significant in the glycinin-dextran conjugate-added WSC. In conclusion, glycinin-carbohydrate conjugates exhibited improved functionalities which were beneficial to facilitating the formation of homogenous microstructure and thus, enhancing the processing quality of WSC. Therefore, the addition of glycinin-carbohydrate conjugates could be considered a feasible alternative to elevate the processing quality and textural properties of whole soybean product.