Abstract This study aimed to investigate the potential of a novel preparation strategy for glycosylated hydrolysate by liquid fermentation in order to provide a high-quality glycosylated hydrolysate. Protein solubility, surface hydrophobicity and antioxidant activity were evaluated. The results of Fourier transform infrared spectra demonstrated the occurrence of glycosylation reaction. The results of Fluorescence emission spectroscope revealed the decrease of tertiary conformation stability. Circular dichroism spectra revealed significant decrease in α-helix and increase in β-sheet and random coil by glycosylation reaction. In comparison with zein hydrolysate, glycosylated hydrolysate had lower surface hydrophobicity but higher in solubility and in vitro digestibility due to glycosylation. Glycosylated hydrolysate presented higher ABTS (2,2'-Azinobis [3-ethylbenzothiazoline-6-sulfonic acid]-diammonium salt) and superoxide radicals scavenging activities as well as Cu2+ chelating capacity. It is concluded that the glycosylation confer an open structure and modified properties of zein, and glycosylated hydrolysate is a potential ingredient with better hydration and antioxidant activities than zein hydrolysate.

Abstract Cordyceps militaris 202 is a potential fungus for biotransformation zein, due to its various proteases, high tolerance and viability in nature. In this article, single factor experiment and response surface methodology were applied to optimize the liquid fermentation conditions and improve the ability of biotransformation zein. The optimized fermentation conditions were as follows: inoculum concentration of 19%, volume of liquor of 130 mL/500 mL and pH of 4.7. Under this condition, the degree of hydrolysis (DH) was 27.31%. The zein hydrolysates from fungi fermentation maintained a high thermal stability. Compared to the original zein, the zein hydrolysates were found to have high solubility, which most likely results in improved foaming and emulsifying properties. Overall, this research demonstrates that hydrolysis of zein by C. militaris 202 is a potential method for improving the functional properties of zein, and the zein hydrolysates can be used as functional ingredients with an increased antioxidant effect in both food and non-food applications.