Quality Analysis and Comprehensive Evaluation of 14 Varieties of Crabapples

Abstract

A comprehensive and intuitive evaluation system for the quality of crabapples (Malus spp.) was established. In this study, 14 varieties of crabapples were tested. The core quality indexes were selected through variability analysis, correlation analysis, and principal component analysis (PCA) to establish the comprehensive quality evaluation model. The reliability of the model was verified by sensory evaluation and cluster analysis. In addition, the characteristics and utilization values of these varieties were investigated by cluster analysis. The results showed that there were significant differences in 18 quality indexes among the varieties and significant correlations among these quality indexes. PCA showed that the cumulative contribution rate of the first 5 principal components was 89.253%. Combining this result with those of correlation analysis, we found that single fruit mass, solid/acid ratio, sugar/acid ratio, and total flavanol content were the major quality indexes of crabapples. According to the comprehensive evaluation model, ‘123 Xiaopingguo’, ‘Longfeng’, ‘Cuifeng’ and ‘Huangtaiping’ had better fruit quality than the other varieties. The antioxidant activity of crabapple polyphenols showed a positive linear correlation with the contents of polyphenols and flavonoids with correlation coefficients of R2 = 0.837 and 0.728 for 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical scavenging capacity, R2 = 0.829 and 0.768 for 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) radical scavenging capacity, and R2 = 0.575 and 0.969 for ferric ion reducing antioxidant power (FRAP), respectively. Likewise, the sensory evaluation scores were linearly correlated with the PCA scores (R2 = 0.862), indicating the reliability of the comprehensive evaluation model. The results of cluster analysis showed that the crabapple varieties could be divided into 4 categories. Category I included M. orbusta and ‘Haihong’, which could be processed into health products with high VC content. Category II included ‘Jixinguo’, ‘Longfeng’, ‘Cuifeng’ and ‘123 Xiaopingguo’, with good taste and being suitable for fresh consumption. Category III included ‘Adam’, ‘Profusion’, M. micromalus, ‘Brandywine’, and ‘Red Splender’, which are suitable for making polyphenols-rich health foods. Category IV included ‘K9 Qingshaguo’, ‘Kelsey’ and ‘Huangtaiping’, which can be processed into preserved fruit, juice, wine and other products. The results were consistent with those of PCA, corroborating the reliability of the model. The comprehensive quality evaluation system can provide a theoretical basis for the development and utilization of different varieties of crabapples and also provide a good scheme for the quality evaluation of crabapples.

Keywords

• crabapple; fruit quality; comprehensive evaluation model; principal component analysis; sensory evaluation; cluster analysis