A Study On The Cultivars Difference Of Rice Quality And Its Relationship With Amylase And Protein Components

In the present study,45rice cultivars (lines) have been chosen to test their11rice qualities including brown rice rate, milled rice ratio, head rice ratio, grain length, grain length/width, chalky rice rate, chalkiness, alkali spreading value, gel consistency, amylase content and protein content. In the meantime, the test also involves investigating the RVA profile characteristics, activity of amylase, a-amylase activity and four protein components including globulin, prolamin, albumin and glutelin of all chosen rice cultivars(lines). The main findings are as follows:1. The research has investigated the overall rice qualities and the evaluations of experimental rice cultivars(lines). The results indicate that:six indexes of rice quality including milled rice rate, head rice rate, chalky rice rate, chalkiness degree, and gel consistency and amylase content show greater coefficients of variation, while the indexes of brawn rice rate, grain length and grain length/width show smaller differences in each rice cultivars(lines).2. Through the analysis of correlations between rice cultivars(lines), the study has found that:the correlation index between brawn rice rate and milled rice rate is0.96**. There exists significantly positive correlation (r=0.53) between milled rice rate and head rice rate. Moreover, head rice rate of different rice cultivars(lines) has significant effects on rice exterior quality and cooking&eating quality and protein components. Furthermore, the correlation between alkali value and gel consistency, head rice rate, chalky rice rate, chalkiness degree presents high significance and it is positively or negatively correlated (r=0.52**,-0.84*,-0.81**,r=0.45**,-0.77*,-0.74**)3. There exist significant differences between the8indexes of RVA profile characters of different rice cultivars(lines) including peak viscosity (PKV), hot viscosity (HPV), breakdown value (BDV), final viscosity (CPV), setback value (SBV), consistence value (CSV), peak time (PeT), plasma temperature (PaT). Among these8indexes, PeT (F=454.455) is the most significant one; then the order comes to SBV(F=310.329)> HPV(F=274.943**)> CSV(F=235.636**)> CPV(F=199.246**)> PKV(F=150.734**)> BDV(F=145.607**) and PaT (F=98.091**) shows the least significance. The current study also shows that RVA profile character of different rice cultivars(lines) shows no significant correlation with milling quality. But it is significantly or extremely significantly correlated with appearance quality and cooking&eating quality. Among rice RVA profile characters, the following character values Peak viscosity (PKV), cool paste viscosity (CPV), Breakdown (BDV) and Consistence value (CSV) demonstrate closest relations with rice quality characters.4. The total amylase activity of different rice cultivars(lines) is not significantly correlated with quality characters. Rice’s α-amylase activity shows close relations with its appearance qualities, cooking&eating quality and protein components, and milled rice rate and brawn rice rate is positively and significantly correlated with a-amylase activity reaching the significant level of0.30and0.34respectively, a-amylase activity is positively and extremely significant correlated with alkali value and gel consistency reaching positive significance of0.38*and0.43*.5. Among4protein components of different rice cultivars(lines), the order of coefficient of variation is globulin> prolamin> albumin> glutelin; glutelin and prolamin is closely related to rice quality, but albumin and globulin demonstrate little influence on rice quality. A positive and extremely significant correlation exists between glutelin, prolamin and rice quality. Moreover,glutelin is significantly related to exterior quality,it also extremely negative correlated with chalky rice rate and chalkiness, the correlation index are r=-0.50**and-0.47respectively. Close relationship also exists between prolamin and processing quality. A positive and extremely significant correlation exists when prolamin is compared with milled rice ratio and head rice ratio, and the correlation index are0.40and0.58**respectively.