Study On The Special Rice For Glutinous Rice Products

Twenty-two cultivars of glutinous rice were used as raw materials to prepare glutinous rice dough and rice cake in this study.Physical properties and pasting properties of 22 cultivars of glutinous rice were investigated.The correlations between rice properties and eating quality of the two major products were discussed.The comprehensive quality evaluation models of the products were obtained by principal component analysis(PCA).In order to determine the raw materials which have good quality,hierarchical cluster analysis(HCA)were used to classify the quality of glutinous rice products.Additionally,stepwise linear regression(SLR)was used to investigate the interrelationship between comprehensive scores and indicators of rice materials.The core indicators effecting the comprehensive quality of products were screened out by SLR.The effects of different storage time on the quality of glutinous rice materials and products were also discussed.The main research results are as follows:(1)The composition(moisture,protein,lipid,total starch,amylose),pasting properties and thermodynamic properties of glutinous rice,as well as the texture properties of products were measured.The correlation between glutinous rice quality and products quality was discussed: there were significant correlations between the moisture content,lipid content,peak viscosity,breakdown,setback,minimum viscosity,final viscosity,gelatinization enthalpy of glutinous rice and texture quality of glutinous rice dough.And there were also significant correlations between the protein content,total starch content,peak viscosity,breakdown,setback,gelatinization enthalpy of glutinous rice and the quality of rice cake.(2)PCA was used in this study,the texture properties of products were set as independent variables.The comprehensive quality evaluation models of the products were obtained respectively.The original indicators were transformed into 3 components.At the same time,the variance contributions and eigenvectors of principal components were formed to calculate the comprehensive scores of the products.The comprehensive scores showed that: Zhennuo is the most suitable for making glutinous rice dough and Wankennuo-1 is the most suitable for rice cakes among 22 cultivars of glutinous rice.(3)According to the similarity of the samples and the squared Euclidean distance,comprehensive scores of products were classified by the method of Groups Linkage.Three clusters were screened out based on squared Euclidean distance at 5.The results showed that Fengnuo-1,Tenuo-2072,Zhennuo and glutinous rice with the same quality as above are supposed to be chosen as materials for producing glutinous rice dough.Fengnuo-1,Enuo-9,No.896,Tenuo-2072,Hongnuo-1,Zhennuo,99-25,Anhui-Taihu nuo,Heinuo,Zinuo,Wankennuo-1 and Wanjingnuo are supposed to be chosen as materials for producing glutinous rice cake.(4)SLR was used to investigate the interrelationship between comprehensive scores and indicators of rice materials,the equations which were established by SLR could be regard as the models for quality prediction of products.As for glutinous rice dough,amylose content and lipid content of glutinous rice are the key indicators that effect comprehensive quality of products.The comprehensive score of rice dough has significant positive correlation with amylose content and negative correlation with lipid content.The glutinous rice dough shows better quality if the amylose content of material is above 2.52% as well as the lipid content is below 1.03%.As for glutinous rice cake,peak viscosity and final viscosity of glutinous rice are the key indicators that effect comprehensive quality of products.The comprehensive score of rice cake has significant positive correlation with final viscosity and negative correlation with peak viscosity.The glutinous rice cake shows better quality if the final viscosity of material is above 581.33 c P as well as peak viscosity is below 2532 c P.(5)2 cultivars of glutinous rice were stored at room temperature for 0,2,4,6,8 and 10 months.The acidity,freeze-thaw stability,pasting properties and thermodynamic properties of glutinous rice were measured.The results showed that those indicators mentioned above were all changed.This caused the hardness of products to increase and the springiness to decrease,which proved that the internal changes of glutinous rice during storage made the products quality worse.