Effect of Resistant Dextrin on the Functional, Thermal and Structural Properties of Cooked Chinese Rice

This study added two types of resistant dextrin (RD), i.e., Bailong (BL) and Luo Gaite (LGT)) to a Japonica (cv. RXY) and an early indica (cv. IP44) rice during cooking and analysed the functional and structural properties of the cooked rice. Compared with no RD addition, 3-10% RD addition induced a declinein cooking time and an incrementin gruel solid loss. Further, 3-10% RD addition increased the hardness, chewiness, and springiness of cooked rice but decreased the cohesiveness. With increases in the added RD amount, the smell, structural appearance, palatability, taste, cool rice texture, and total score of the cooked rice all increased; the peak time and pasting temperature increased, but the peak, final, breakdown, and setback viscosities all significantly decreased. The enthalpy, conclusion temperature of gelatinisation, and gelatinisation peak width and height all decreased with increasing RD amount, but the peak temperature of gelatinisation increased. The addition of 3-7% RD did not change amylopectin ageing, but 10% RD significantly increased amylopectin ageing. RD addition reduced the protein weakness degree and starch breakdown torque of rice doughbut appeared to increase the amorphous and crystalline regions of cooked rice. The addition of 10% BL or LGT induced the formation of α-helix and random coil secondary protein structures in cooked rice, with optimal cooking properties and total sensory score. Microstructure analysis further showed that low-viscous RD induced the formation of new gel-like structures. In conclusion, 3-10% RD addition in cooking rice decreases amylose recrystallisation, weakens the protein structure, and induces new gel-like structures, enhancing the hardness, chewiness, adhesiveness, springiness, and sensory score of cooked rice. This study is useful for developing functionalcooked rice.