Comprehensive evaluation of polyphenols from 35 apple varieties based on principal component and cluster analysis

The purpose of this research was to investigate the variations between apple varieties and polyphenols, varieties and contents of polyphenols from 35 apple varieties were analyzed, interrelationships between apple varieties and polyphenols were investigated by correlation, principal component ( PCA) and cluster analysis ( CA) . Results showed that there were obvious differences between apple varieties and polyphenols, some polyphenols had the significant relationship.The first four components represented 75% of the total variability on the base of the total variance explained and screen plot of principal component analysis.The first principal component was related to hyperoside, procyanidins B2, and the second principal component was related to phloridzin. The sample score plots visually displayed the relationship between apple varieties and polyphenols. The varieties of Qinyang, Gala Ⅰand Gala Ⅱwere located on the first quadrant of the plot for PC1 and PC2, these apple varieties were early-maturing varieties, Brachyplast Huaguan, Huaxing Huacui were located on the second quadrant of the same plot, they were middle-maturing varieties, Golden Delicious, Fuji, Qinguan were located on the fourth quadrant of the same plot.CA classified 35 varieties into five main groups on the basis of the measured parameters, which was consistent with the results of PCA score plots.Comprehensively evaluated of different apple varieties and polyphenols will provide the theoretical support.