The Study On Characteristics Of Rice Processing And Quality Evaluation

Rice is the main food crops in our country. With the improvement of living standards of our people, the people's requirements for rice is also been getting higher and higher, not only to be fed, but also to be ate well.However, rice which is planted in southern China mostly is indica. Although their output is large, the eating quality of indica is not good cause the reason of poor sales in recent years. Some experts said that one of the way is the deep processing of rice and increase the added value of rice, mean while, indica characteristics make it to be a high-quality raw material for processing rice noodles.Therefore, it is very significance to increase the study on characteristics of rice processing and technology evaluation of rice quality.In this thesis, we studied on all aspects quality of120kinds of rice which were cultivated in China's major rice growing areas, analyzed the correlation between quality traits and taste value, made the further study on the adaptability of its processing of rice noodles,and also did the principal component cluster analysis for the varieties indicators of rice, established the processing regression equation of rice noodles. We hope that throught this study, we can provide a theoretical basis for evaluation of rice quality, provide a direction for ricedeep processing and cultivation of high-quality indica rice varieties.In this article, various aspects index measurement of rice were collected, including milling quality (brown rice rate, milled rice rate, complete milled rice rate), appearance quality (percentage of chalky grains, chalkiness, rice type of the fine grain),physical and chemical quality (moisture content, amylose content, protein content), cooking and eating quality (gel consistency, alkali spreading value, water absorption, etc.), and also the RVA characteristic spectrum of rice, the NIR spectra by a near infrared analyzer. Then we made a study on the correlation between various indicators, made the principal component analysis for some indicators of the rice, made the sensory score on rice noodles which processed by the100kinds of rice, made the principal component cluster analysis by the sensory score of rice noodles quality, established the regression equation of sensory score, the main results are as follows:(1) By analyzing the correlation between each quality of rice, we found that there is significant or very significant correlation between some rice quality and taste value, there is very significant negative correlation between taste value and amylose content and protein content, there is very significant correlation between moisture content and taste value, there is very negative significant correlation between percentage of chalky grains and taste value, there is very significant correlation between Gel consistency and taste value. By the compare of Near-infrared and conventional measured value, we found that there is negative significant or very negative significant between protein content, grain length, Chalkiness which measued by the two method, there is very negative significant between protein content and taste, there is very significant between rice yield and taste value by the method of Near-infrared.(2) Made the principal component analysis on13quality indicators of the rice, five principal components were got, The first principal component is shape factor, the second principal component is physical and chemical factor, the third principal component is milled rice rate form factor, the fourth principal component is chalky grain rate form factor, the fifth principal component is water factor the cumulative contribution rate has reached77.71%of the top five root characteristics which can basically reflect the rice quality.(3) After the analysis of the RVA spectrum characteristics of rice and the correlation analysis between the RVA spectrum characteristics and some quality of rice, we found that there is obvious differences in the various indicators of Rice RVA spectrum characteristic which can be used to distinguish different types of rice. There is very significant correlation between break down and taste value, there is very negative significant correlation between breakdown and amylose, there is very significant correlation between retrogradation value and amylose, there is very significant correlation between Gel consistency and breakdown, there is very negative significant correlation between consistency and retrogradation value, there is significant correlation between water absorption and final viscosity, there is significant correlation between water absorptionand retrogradation value, there is significant correlation between Volume expansion and final viscosity,there is very significant correlation between Volume expansion and breakdown, there is negative significant correlation between the chalkiness and the peak viscosity, there is very negative significant correlation between the chalkiness and breakdown, there is very significant between the chalkiness and Retrogradation value, there is negative significant between the time when reached the peak viscosity and complete milled rice rate, there is significant correlation between Gelatinization temperature and the time when reached the peak viscosity, beside there is not significant correlation between the tetrogradation value peak viscosity, there is very negative significant correlation between the tetrogradation value and breakdown, there is very significant correlation between the tetrogradation value and the other index.RVA Profile can reflect the the good taste value or the bad between different indica rice very well. Beside the breakdown, setback, back to cold recovery value is the three most important indicators of the characteristics of RVA spectrum, breakdown value850-1248RVU, setback<1100RVU, consistence<180RVU, reply the breed generally good eating quality.(4) When rice amylose content20.3-22.7%, protein content8.8-11.1%, moisture content11.2-14.4%, consistence value559-921RVU, breakdown value795-1729RVU, gel consistency44-67.5mm, volume expansion ratio3.29-4.07, the sensory evaluation score production of rice noodles is better. Seven dominant factor were extracted which had significant affect on sensory score of rice noodles were divided into three major types, each type of rice corresponds to the different sensory scores, the best sensory score of rice noodles is made by the second type of rice, and we got the regression equation from the principal component and the rice sensory scores:v=-0.265X z7+0.168X z5-0.129X z3.