Abstract: In order to improve the cooking quality of rice, to retard the retrogradation of cooked rice and to improve the digestibility of cooked rice, we evaluated the effects of three low-energy sweeteners of fructo-oligosaccharide, sorbitol and maltitol at different concentrations on the water absorption rate and the proportion of amylase in raw rice, as well as the hardness, microstructure, thermal characteristics and digestibility of cooked rice. The results showed that all the three sweeteners could improve the water absorption capacity of raw rice and reduce the hardness and digestibility in vitro of cooked rice. The water absorption rate after 25 min immersion was 11.18% higher in 1.6% fructo-oligosaccharide solution than in blank control, and the proportion of amylose, gelatinization enthalpy and hardness after 24 h decreased by 7.36%, 22.91% and 21.79%, respectively. Compared with the other treatments, 1.6% fructo-oligosaccharide treatment significantly reduced gelatinization enthalpy and crystallinity, and showed better microstructure and anti-retrogradation ability. This study provides a basis for deep processing of rice and the development of instant rice products.

Key words: fructo-oligosaccharide, sorbitol, maltitol, rice, cooking quality, digestibility