Comprehensive Evaluation of Quality of Laoxinghuang in Different Aging Years

To solve the problem of judging the aging years of Laoxianghuang, the relationship between the changes of the physical and chemical qualities and the aging years were analyzed by means of variance analysis and principal component analysis. The physical and chemical qualities of Laoxianghuang included volatile substances, physical and chemical components, and functional components from 6 different aging years were analyzed. TOPSIS method was used to evaluate the different aging years of Laoxianghuang. The results showed that with the extension of aging years, the types of volatile substances and the contents of terpenes increased significantly. The water content decreased and then increased with the extension of aging years. The contents of total sugar and NaCl, pH showed a decreasing trend during the aging process. The contents of total flavonoids and total polyphenols increased gradually, whereas they were not obvious after 8 years of aging. The content of anthocyanins decreased gradually during 8 years of aging (33.33% lower in 8 years of aging than in 3 years of aging), and then gradually increased. Based on the coefficient of variation, correlation and index importance, the coefficients of variation of β-bisabolene and NaCl contents in the first principal component were more than 10%, and there was no significant correlation between them. The variation coefficient of terpinolene in the second principal component and the variation coefficient of total flavonoids in the third principal component were large. The results of the variation coefficients indicated that the contents of β-bisabolene and NaCl, terpinolene and flavone were significantly different in different aging years, which showed that those four indexes had good discretization. Therefore, these four indexes were selected as the core evaluation indexes. TOPSIS comprehensive evaluation method showed that the longer the aging years of Laoxianghuang, the higher the comprehensive score. This evaluation method could provide a more reliable basis and standard for the identification of the aging years of Laoxianghuang.