Effect of Sucrose and Gluten on Glass Transition, Gelatinization, and Retrogradation of Wheat Starch

摘要

Differential scanning calorimetry (DSC) was used to study effects of sucrose and gluten on wheat starch glass transition, gelatinization, and retrogradation. Glass transition temperature (T_g) of wheat starch decreased as the ratio of sucrose or gluten to starch increased. Both peak temperature (T_G) and enthalpy values of gelatinization endotherm increased or decreased with increasing ratio of sucrose or gluten, respectively. Wheat starch gel with no sucrose and gluten recrystallized up to 4 weeksof storage at 4°C, whereas those with sucrose and gluten completed recrystallization within 1 week. Both wheat starch gels with no sucrose and gluten, and those with sucrose and gluten at storage temperature of 32°C recrystallized up to 4 weeks, with wheat starch-sucrose-gluten (1:0.5:0.12) system, which had highest ratios of gluten and sucrose to starch, showing lowest recrystallization. Nucleation and propagation rates of starch gel recrystallization based on polymer crystallization principles can be converted into peak width (δT) and peak temperature (T_R) of retrogradative endotherm by DSC, because higher nucleation rate at storage temperature of 4°C close to T_g showed higher δT, whereas higher propagation rate at 32°C (close to T_G) had higher T_R.