Effects Of Cooking On Edible Quality Of Rice Based On Evaluation Of Physical Property Combined With Aroma

In this study, ten representatives commercial rice (japonica rice and indica rice)were selected to investigate the cooking quality of rice. We analyzed the raw materials from various aspects include sensory analysis, such as rice traits and basic composition(moisture, protein, fat, starch, amylose content determination), aroma, cooked rice quality (water absorption rate, expansion rate, iodine blue value, color difference and gel consistency) and textural properties (hardness, viscosity, elasticity, chewiness etc.).The purpose of this study was to establish a comprehensive evaluation method of rice taste quality, which provides a good theoretical basis for the optimization of rice cooking process and the improvement of taste quality. The results of sensory evaluation showed that the japonica rice’s optimum rice water ratio was 1: 1.2 and indica rice’s was 1: 1.3 when use electric cooker, pressure cooker and electric steamer cooker, the ratio was 1: 1.3 (japonica rice) and 1: 1.5 (indica rice) when use microwave process.From the steamed rice quality, when the expansion rate was 140～160%, the water absorption rate of 100～120%, iodine content was more than 0.5, L* value greater than 80, glue length was greater than 4.5 cm, indicating that the starch gelatinization degree was good, the soft hardness and viscoelasticity of rice were moderate, and the eating quality of rice was the best. When the moisture content of rice was above 11% and the amylose content was less than 25%, the viscosity and hardness of rice were the best. In addition, the quality and hardness of rice measured by texture analyzer show that, the cooking quality of rice cooked with rice cooker is the best.Through the use of electronic nose and headspace solid phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) to analysis of volatile components in the different cooked rice, and the key flavor components in rice were screened by multivariate statistical analysis. The results showed that the volatile components of indica rice were 149, while the jasmine rice were detected by 124. The volatile components of rice were significantly reduced after cooking. The main volatile components of japonica rice (main aroma substances) included hexanal, 2-heptenal, 1-octene-3-alcohol, 2-octanone, the main volatile components of indica rice (main aroma)included 1-nonanol, 2-octyl-1-decyl alcohol, the volatile components of different rice and cooked rice showed different flavor. Based on the principal component analysis of electronic nose, the raw materials of rice (japonica rice and indica rice) were divided into two regions, the difference was 94.08%, and the rice was also divided into two regions, the difference was about 91.02%.