Mechanistic insights into polyol enhancement on mechanical and hydration characteristics of rice starch gels

Rehydration difficulties and high cooking loss restrict the development of dried rice noodles. This study investigated the effects of polyols-glycerol, erythritol, and xylitol on the rehydration, structure, and mechanical properties of rice starch gels. Results showed that polyols enhanced the mechanical strength, and significantly reduced water contact angle, melting enthalpy, and crystallinity of the gels. Among them, glycerol most effectively improved rehydration and tensile performance, reducing rehydration time by 64.07 % and increasing tensile strain by 50.56 %. When the amount of polyols was 10-20 %, xylitol was the most effective in shortening the rehydration time. When the amount was 30-40 %, all three polyols markedly reduced rehydration time with no significant differences. Xylitol also showed the strongest inhibition of starch retrogradation, decreasing relative crystallinity by 68.52 %. Furthermore, a decrease in the number of hydroxyl groups led to increased molecular flexibility, which gradually improved the tensile properties of the starch gels.