Research On Quality Characteristics Change Of High-quality Grain In Major Production Areas Of Jiangsu Province

Rice is the most important staple food in China.In recent years,with the improvement of people's living standard,there is an increasing demand for high-quality rice.However,the high-quality rice was affected by the cooperation of many factors,such as cultivars,growth climate and processing conditions.The purpose of this study was to explore the relationship between quality of high-quality rice and the growing climate and variety,and to ensure the stability of processing quality and eating quality of high-quality rice.In this study,72 japonica rice samples harvested in the autumn of2019 and 2020 in Rudong County,Hai 'an City,Xinghua City,Funing County,and Huai'an District of Jiangsu Province were taken as experimental samples.The key factors affecting rice quality indexes,such as appearance quality,composition,cooking texture,and gelatinization characteristics,were studied in combination with the growing environment.The quality changes of high-quality varieties were investigated from the perspectives of starch characteristics and taste characteristics.The main contents and results are as follows:1.Investigation on quality of high-quality rice in main production areas of Jiangsu Province.The quality indexes of appearance,composition,cooking texture and gelatinization characteristics of the samples were determined in this paper.It was found that the overall quality of rice in 2019 was lower than that in 2020,and the milled rice rate reached over 92%.In addition,the quality stability of Nangjing 9108 was higher than other cultivars,and the difference of cultivars were the main reason for the difference of cooking texture and gelatinization.The results of cluster analysis showed that the difference of rice quality was caused by the cultivar difference.The correlation results showed that accumulated temperature and average temperature had significant effects on rice appearance and rice component content during the growth cycle,among which the correlation coefficients between accumulated temperature and average temperature and chalkiness degree were-0.169** and-0.27**,and the correlation coefficients between accumulated temperature and average temperature and protein content were 0.376** and 0.217**.2.Research on starch properties of high-quality rice.The rice cultivar Nanjing9108 planted in five regions was selected to extract starch according to the solid-liquid ratio of 1:10 alkali method,and the starch composition,thermodynamic gelatinization characteristics and optical spectrum were measured.The results showed that: the whiteness of starch reaches 94.6%,and the grain size distribution at 10?m and 100?m shows a bimpeak.The tangent Angle of starch paste loss was always less than 1,showing a typical weak gel fluid.The crystal shape was not affected by the growing environment,but the intensity of the diffraction peak was passivated by the growing climate.The results of cluster analysis showed that rice starch properties were little affected by growing environment.The correlation results showed that the content of amylose and damaged starch had a significant effect on the processing characteristics of starch.The correlation coefficients between amylose and peak viscosity and crystallinity were 0.572** and 0.409**,and the correlation coefficients between damaged starch and peak viscosity and gelatinization time were-0.375* and-0.346*.3.Research on eating characteristics of high-quality rice.The rice of Nanjing 9108 was cooked according to the ratio of rice to water 1:1.3.The quality of cooked rice processing was determined from the aspects of physical properties,texture,taste score,flavor and taste.The results showed that the water absorption,swelling and absorbance of rice reached 120%,1.5 and 30%.In addition,the overall texture of cooked rice was moderate hardness,strong viscosity,elastic mouth,slightly better appearance and slightly better taste,and the comprehensive score of food taste value reached more than80.In terms of flavor and taste of rice and cooked rice,the contribution rate of rice and cooked rice main components reached 95% and 94.24%,respectively.It showed that the flavor and taste of the same cultivars rice were distinguished obviously.There were49 kinds of volatile substances in rice,and 54 kinds of volatile substances in the cooked rice.The results of cluster analysis showed that there were significant differences in food taste of Nanjing 9108 rice from different regions,and volatile matter of rice in different years had obvious difference.