Abstract: 【Objective】 The aim of the paper was to investigate the variations in the comprehensive quality of peaches and nectarine chips from the different cultivars and establish scientific evaluation models for peach and nectarine chips. 【Method】 Peach and nectarine fruit from 49 varieties grown in the north of China were selected for the testing materials. 17 quality evaluation indexes were measured, including organoleptic quality indexes (e.g. color, hardness, crispness, explosion ratio, and so on), physical and chemical characteristic indexes (e.g., soluble solid content, crude fat content, crude protein content, crude fiber content, and so on) and processing quality indexes (output ratio and rehydration ratio). The method of a variable coefficient was used to investigate the differences in quality evaluation indexes from different peach and nectarine cultivars. The relationship between these indexes and the characteristic indexes were selected by factor analysis (FA). The weights and the levels of the characteristic indexes were calculated by an analytic hierarchy process (AHP) and a range analysis method, respectively. The levels in cultivars effectively were classified by discrimination functions which were obtained by K-means cluster (KC) and discriminate analysis (DA). 70% of the samples were selected as the testing samples, and the others were used as the verification set data, which could verify the fitness of the functions. 【Result】 (1) 17 quality evaluation indexes dispersed with the coefficient of variation ranging from 0.70%-344.02%. (2) Five characteristic indexes were determined based on the method of FA, which explained 74.626% of the total variances. The first principal component (PC1) was related to reducing sugar content and sugar-acid ratio, which were the taste quality factors. The principal component (PC2) was related to the output ratio and rehydration ratio, which were the processing quality factors. The third principle component (PC3) was related to the L value and b value, which were the color quality factors. And the fourth and fifth principal components (PC4 and PC5) were related to the crude protein content and explosion ratio, respectively, which had higher weights than the others. Five quality evaluation indexes were selected as the characteristics indexes, namely, reducing sugar, rehydration ratio, L value, crude protein content, and expansion ratio. (3) Based on the AHP, the weights of the characteristics indexes were 0.0824, 0.1724, 0.2732, 0.0480, and 0.4240, respectively. Also, the scoring standard of the characteristic indexes were established. (4) Discrimination functions of different grades were established, which had satisfactory recognition accuracy up to 100%, and only one sample was discriminated inaccurately. Ruipan19, Delaifulaika, and Dajiubao were the best cultivars used to produce peach and nectarine chips, Ruipan 21, Juhuang, and Yanhong were the good cultivars used to produce peach and nectarine chips, and Rupan 20, Sengelin, and Huangjinxiu were the worst cultivars used to processing peach chips. 【Conclusion】 Peach and nectarine chips’ comprehensive quality can be evaluated by 5 characteristics indexes, namely, reducing sugar content, rehydration ratio, L value, crude protein content, and expansion ratio. The grading standard and the scoring standard of the 5 indexes set up a scientific foundation for evaluating peach and nectarine chips’ quality. The established discrimination functions were effective in discriminating peach and nectarine chips’ quality.

Key words: peach chips, quality evaluation, characteristic indexes, factor analysis, analytics hierarchy process, discriminant analysis