Rice Proteins Affect Cooking And Eating Quality Of Cooked Indica Rice

Rice protein content is second only starch material in rice, and is one of the main factors affect rice quality.Clarify the protein content and components influence on rice cooking and eating quality,it is have great significance in improvement the rice eating quality and breeding and evaluating the cooking and eating quality in the future. This study found an exact method to extraction and determination of protein four components content in rice,it provide accurate and reliable data for the analysis of protein influnence cooking and eating quality of rice.In order to clarify the impact of the indica rice protein on rice cooking and eating quality,this study analysis the total protein, protein four components and protein sub units composition influence on the rice cooking and eating quality, the starch pasting properties and texture of cooked rice.The specific results for the following aspects:1. Improvement and establishment of a set of technology to determine the total rice protein and protein four components (glutelin, prolamin, globulin, albumin)content. The study through the experiments identified four kinds protein optimal extraction conditions, respectively for glutelin:0.1mol/L NaOH,2h, extract three times; prolamin:70%ethanol,4h, extract three times; globulin:5%NaCl,4h, extract three times; albumin:pure water,4h, extract three times. Used continuous flow analyzer for the determination of the total protein and protein four components,the result of the method is accurate and reliable, high precision, low detection line and significantly better than Coomassie brilliant blue method.2.The study analysis the correlation between protein with RVA characteristic value,the result shows that the rice total protein content is significantly negatively correlate with the hot paste viscosity and final viscosity, and the correlation coefficient is-0.39and-0.43, respectively.Glutelin content is significant or highly significant negative correlation with hot paste viscosity, final viscosity and setback value. Prolamin content is highly significant negative correlation with breakdown value,and highly significant positive correlation with setback value. Globulin content is highly significant negative correlation with breakdown value, hot paste viscosity and final viscosity.3.The total protein content and glutelin,prolamin,albumin content have no significantly correlate with DSC characteristic value,and globulin content is significant or highly significant positive correlation with DSC start temperature,peak temperature and end temperature,this result prompts that the globulin content improved may increase the rice pasting difficulty.4.In the protein content lower sample, total protein and protein four components is less effect on the cooking quality of indica rice, and in high protein content of the samples, globulin and prolamin content may make cooking quality of indica rice becomes poor.5.The total protein content is positive significantly correlate with rice hardness; albumin is positive significantly correlate with rice hardness and gumminess. Glutelin content is positive significantly correlate with rice hardness.Prolamin content is positive significantly correlate with rice cohesiveness and springiness. Globulin content is significant or highly significant positive correlation with cohesiveness and springiness.There is some difference between every kinds protein in the ratio of total protein and every kinds protein correlaton wiht texture analyzer characteristic values. This result prompts that the higher the indica rice protein,the greater rice hardness.Prolamin and globulin content on the rice cohesiveness and springiness is reverse, in which proamin is produce certain positive role and globulin is negative.6. Path analysis showed that the decisive role of indica rice eating quality is protein content, especially albumin content and amylose content, and protein content and amylose content have some negative impact on eating quality.The path coefficient of albumin protein content on the evaluation score of cooking rice,adhesiveness, cooking rice integrity, springiness and hardness is all negative values and achieve significant or very significant level, and the coefficient of determination is the high.7.The study show that there have a certain correlation between the total protein subunits content with the characteristic values of RVA and texture of cooked rice and eating quality indicators, with no significant correlation between the DSC eigenvalue.57kDa subunit content have a significant positive impact on eating quality on the indica rice.