Quality Evaluation of Different Varieties of Oat Based on Principal Components Analysis and Cluster Analysis

In order to study the nutritional value of oats and establish an oat quality evaluation system, 10 oat varieties were selected to determine contents of 9 nutritional components. The variability of various nutritional indexes among oat varieties was analyzed. The quality of oats was comprehensively evaluated by principal component analysis and cluster analysis, and the evaluation model of oat quality was established. The results showed that the oleic acid content of "Huazao No.2" was significantly different from that of other varieties (P<0.05), there was no significant difference between the remaining 8 fatty acids (P>0.05), there was no significant difference in polyunsaturated fatty acids (P>0.05), and there were significant differences in β-glucan content, total phenol content, flavonoid content, water content, starch content and fat content among different oats. Except for water and polysaturated fatty acids content, the coefficient of variation of other nutritional components was more than 10%. "Huazao No.2" was rich in linoleic acid, β-glucan content of "GL380" was up to 4.10%, "Zhang No.14" was rich in flavonoids, containing 4.14 mg RE·g FW^-1, and "Huazao No.2" had the highest protein content of 24.42%. Principal component analysis was conducted for each quality index, and the cumulative variance contribution rate of the four extracted principal components reached 80.006%, reflecting most of the information of the original index. Among all the samples, the varieties with high comprehensive scores in principal component analysis were "026", "H44" and "Zhang 14", indicating that the contents of the first principal components, namely total phenols and polyunsaturated fatty acids, were relatively high and the comprehensive quality was relatively good.In order to quantify the similarity between samples and reduce the interference of deviation samples, cluster analysis was conducted on the basis of principal component analysis. According to the importance of variables (flavonoids > fat > starch > total sugar > water > β-glucan > protein > polyunsaturated fatty acid > total phenol), 10 kinds of oats were divided into 3 categories, the first category included "026", "Huazao No.2", "Bayou No.1", "1048-109" and "Huawan No. 6", the second category included "Zhang No. 14", "029", "Zhang No. 13" and "H44" and the third category was "GL380".The results of this study can provide reference for the quality evaluation of different varieties of oats, and provide theoretical basis for the breeding and development of oats.