Abstract: The effect of Gleditsia sinensis Lam. gum (GSLG) added in different proportions (1%, 3%, 5% and 7%, based on the dry mass of corn starch) to corn starch on its retrogradation during cold storage (CS) was investigated in this study by rheological and texture characterization, differential scanning calorimetry (DSC) and low-field nuclear magnetic resonance (LF-NMR) imaging analysis. Dynamic rheological analysis showed that the elastic modulus of corn starch increased with refrigeration time; addition of GSLG decreased the change in elastic modulus and inhibited the short-term retrogradation of corn starch to some extent. The hardness of starch gels increased with cold storage time but decreased with the addition of GSLG. The results of DSC showed that the aging rate of mixed systems decreased with increasing addition of GSLG. Using LF-NMR, a comparative analysis of the proportions of free, bound, and immobile water in starch gels before and after addition of 5% GSLG was conducted, which confirmed that the gum had a large effect on the water distribution in the gels. This study further enriches the theoretical understanding of the effect of plant gums on the aging property of starch.

Key words: corn starch; Gleditsia sinensis Lam. gum; aging rate; water distribution