Optimization Of Slow-digesting Rice Preparation Process And Taste Quality Research

Rice is a good source of carbohydrates,vitamins,and protein.The glycemic index(GI)of refined white rice is high,and the production of rice with slower digestion has become a hot spot in the food field by modifying rice starch.In this thesis,Indica Rice(IR)and Japonica Rice(JR)with different amylose contents were selected for research.By changing the hydrothermal treatment conditions,the processing technology was optimized using temperature difference,pressure difference,and cyclic temperature change crystallization methods.The physicochemical properties,structural characteristics,and nutritional value of the rice were systematically analyzed.The main findings are as follows:(1)The optimal preparation process of slow-digesting rice was optimized using singlefactor experiments and orthogonal tests,yielding: 50% moisture addition,30 min processing time in autoclave,and 48 h refrigerated aging time.the glycemic production indices of IR-P and JR-P were 50 and 54,respectively,after processing.(2)After the treatment,the percentage of white core granules decreased the appearance quality was improved.the results of texture analysis showed an increase in hardness and chewiness.the SEM results showed that the starch granules were more tightly bound and the internal pores were significantly reduced,forming a dense and rigid structure.During the treatment,the starch granules underwent a large degree of swelling and protein disintegration,and the results indicated that more resistant starch and straight-chain amylopectin complexes were produced and the solubilization of straight-chain starch was inhibited.(3)The results of DSC and RVA showed that IR had a higher gelatinization temperature and gelatinization viscosity than JR,indicating that the crystal form of the former was more ordered and contained more amylose.The results of FTIR and LF-NMR showed an increase in the ratio of 1047 cm-1/1022 cm-1,a decrease in the ratio of 1022 cm-1/995 cm-1,and an increase in free water content.This indicates an increase in the degree of internal order,crystallinity,aging degree,and digestion rate of slow digestible rice after treatment.The XRD results showed a shift from A-type crystalline peaks to V-type peaks in IR and JR,indicating the production of more resistant starch and straight-chain amylopectin complexes.(4)The results of the electronic nose and PCA analysis showed that the aroma response values of the treated rice increased and produced differential and specific volatile aromas.The GC-MS results showed that IR and JR detected 38 and 23 volatile aroma substances,respectively,and IR-P and JR-P detected 52 and 27 volatile aroma substances,respectively,indicating the production of more volatile flavor compounds.The results of the sensory evaluation showed that the overall sensory scores of the four samples were high and the recognition was high.