Development of the Quality Evaluation System of High Protein Recombinant Rice by Principal Component Analysis

In order to explore the relationship among quality indexes of high protein recombinant rice, 16 kinds of high protein recombinant rice were prepared by extrusion using broken rice and 16 kinds of common protein powder as raw materials. The texture properties, cooking characteristics, gelatinization degree, water solubility index, water absorption index and expansion degree of high protein recombinant rice were determined, and the comprehensive scores of different high protein recombinant rice were calculated by principal component analysis. The quality evaluation index of high protein recombinant rice was screened by stepwise regression, and the comprehensive evaluation system was constructed. The results showed that the cooking quality indexes and texture quality indexes of high protein recombinant rice prepared by different proteins were quite different. The cumulative contribution rate of the three principal components extracted by principal component analysis reached 85.148%, which were 59.4725%(X₁), 17.527%(X₂) and 8.149%(X₃), respectively. Gumminess, dissolution of solid material, hardness, water absorption index, chewiness, cohesion, gelatinization degree, resilience and rice water absorption played a major role in the first principal component, while elasticity, expansion and iodine blue value played a major role in the second principal component. Water solubility index was an important index of the third principal component. Taking the comprehensive score of high protein recombinant rice obtained by principal component analysis as dependent variable (F value), and each index value participating in principal component analysis as independent variable, the theoretical model of comprehensive quality evaluation of high protein recombinant rice was established by stepwise regression analysis: Y=0.915X_gumminess+0.208X_{gelatinization degree}−0.475X_{dissolution of solid material}+0.436X_resilience. According to the model, the best quality of high protein recombinant rice was rice protein recombinant rice, followed by soybean protein isolate recombinant rice, having a good agreement and significant positively correlated with the comprehensive score of principal components (P<0.01), which further confirmed that the model had high reliability.