Fruit quality analysis and comprehensive evaluation of 30 bayberry varieties

Abstract:【Objective】There are differences in fruit quality among different bayberry varieties. Understanding fruit quality traits can provide valuable information and evaluation tools for breeding and developimg excellent bayberry varieties. Therefore, the purpose of this study was to explore the comprehensive quality traits and their differences of bayberry fruit, and to establish an efficient evaluation system for the quality of bayberry fruit.【Methods】In order to explore the fruit quality traits, the fruits of 30 bayberry varieties were collected in this study, and 20 indexes such as average weight, fruit shape index, edible rate, fruit hardness, total soluble solids content, titratable acid, glucose, sucrose, fructose, ascorbic acid (AsA), malic acid, citric acid, amino acid (AA), proanthocyanidin, flavonoid, total phenol, calcium (Ca), iron (Fe), zinc (Zn) and selenium (Se) were measured. The fruit quality of different bayberry varieties was analyzed and evaluated by using SPSS17.0 statistical software for coefficient of variation analysis, correlation analysis, principal component analysis and comprehensive score ranking. 【Results】There were significant differences in the fruit quality indexes among 30 bayberry varieties, and the coefficient of variation ranged from 3.13% to 78.94%. The fruit shape index was between 0.92 and 1.06, and the edible rate was between 83% and 94%, indicating that the coefficient of variation of fruit shape index and edible rate was small. In terms of fruit internal quality, the content of sucrose in bayberry fruit was the highest, followed by fructose and glucose. Among the organic acids, the content of malic acid varied greatly among different bayberry varieties, but the content of citric acid varied lit-tle. In terms of functional nutrients in fruits, the coefficient of variation of proanthocyanidins among different bayberry varieties was relatively high, and the coefficient of variation of AsA, flavonoids and total phenols was medium. Correlation analysis showed that there was a certain correlation between the quality indexes of different bayberry varieties, and some indexes were even highly correlated. Average fruit weight was significantly and positively correlated with malic acid, and significantly and negatively correlated with Fe and Zn contents in fruits. There was a significant positive correlation between fruit shape index and AsA content. There was a significant negative correlation between edible rate and titratable acid. Fruit hardness was significantly and positively correlated with glucose and significantly and negatively correlated with Ca contents. There was a significant correlation between glucose, sucrose, fructose and soluble solids. There was a significant positive correlation between AsA and citric acid and proanthocyanidin content. There was a significant positive correlation between citric acid and proanthocyanidin content. Total phenols were significantly and positively correlated with malic acid and proanthocyanidins, and extremely significantly and positively correlated with flavonoids content. In addition, the mineral elements in the fruit were significantly or extremely significantly and negatively correlated with some fruit nutrient elements. The principal component analysis of 17 traits of 30 different bayberry varieties was carried out by eliminating the sensory indexes with less variation, such as shape index, edible rate and fruit hardness. Six principal components with eigenvalues greater than 1 were extracted, and the cumulative contribution rate was 80.017%. The contribution rate of principal component 1 was 25.155%, and the first principal component was mainly determined by citric acid, AsA and proanthocyanidin. The contribution rate of principal component 2 was 20.085%, and the second principal component was mainly determined by soluble solids content and fructose. The contribution rate of principal component 3 was 13.048%, and the main components determining the size of the third principal component were flavonoids and total phenols. The contribution rate of principal component 4 was 8.483%, and the main factor determining the size of the fourth principal component was malic acid. The contribution rate of principal component 5 was 6.835%, and the main factor determining the size of the fifth principal component was titratable acid. The contribution rate of principal component 6 was 6.409%, and it was mainly Se mineral element that determined the size of the sixth principal component. The first and third principal components could mainly represent fruit function, the second, fourth and fifth principal components could represent fruit flavor, and the sixth principal component mainly could represent fruit mineral nutrition. Soluble solids content, titratable acid, ascorbic acid (AsA), malic acid, total phenols and Se mineral element were selected as the core indicators for the evaluation of fruit quality traits of bayberry by comprehensive correlation analysis and principal component analysis. By principal component analysis, Changshuzaohong, Muyemei, Xiaoheitou, Dayexidi, Xiaoyexidi, Zaoshuyihao and Xishanzaoshu got the higher scores.【Conclusion】Through the comprehensive analysis of the fruit quality of 30 bayberry varieties, the conclusions are as follows: soluble solids content, titratable acid, AsA, malic acid, total phenols and Se mineral element can be used as the core indicators for the quality evaluation of bayberry. Correlation analysis and principal component analysis can be used to provide a reference basis for the screening of excellent bayberry varieties.