Screening of factors for evaluating freeze-dried strawberry powder based on multivariate statistical analysis

The quality traits of freeze-dried fruit powder of 21 strawberry cultivars were evaluated based on descriptive statistics, correlation analysis, principal component analysis and cluster analysis. The results indicated that only variation coefficients of DPPH radical inhibition rate and b^* value were less than 6% among the 21 quality indexes and the others were larger. Meanwhile, there were different degrees of correlation among the indicators. The principal component analysis method was used to concentrating representation of interrelated variables and the first six principal components together account for 81.895% of the total variability. Among 21 strawberry cultivars, the principal component comprehensive scores of ‘Fenghuang’, ‘Meng’, ‘Jiazhangji’ and ‘Zijinxiangyu’ were higher. According to PCA and clustering results, eight core indexes including hygroscopicity, fructose content, a^* value, soluble protein content, V_C content, pectin content, yield and L^* value selected from six categories of principal components could replace the original 21 indicators to simplify the evaluation indexes of freeze-dried strawberry powder. The results of this study would provide a theoretical basis for evaluating the quality indexes of freeze-dried strawberry powder.