Quality Difference Analysis of Raw and Wine-Processed Polygonati Rhizoma Based on Correlation Between Color and...

The dried rhizome of Polygonati Rhizoma, known as Huangjing, is commonly used clinically in both its raw and wine-processed forms. However, the distinctions in quality between them remain unclear, and the methods for identifying them are considerably intricate. This study aimed to analyze the differences in color and changes in key components between raw and wine-processed Polygonati Rhizoma, to reveal the correlation between the color and chemical components of Polygonati Rhizoma before and after processing, and to provide a reference for the identification and quality evaluation of Polygonati Rhizoma processed products. Based on the subjective judgment of the external properties of raw and wine-processed Polygonati Rhizoma by the eyes, an electronic eye was used to quantify their color objectively. The contents of extractum and polysaccharide were determined, and HPLC fingerprint profiles of raw and wine-processed Polygonati Rhizoma were also established to represent their chemical composition characteristics systematically. Chemometric analysis was performed using SIMCA 14.1 to evaluate their quality differences, while SPSS 27.0 and Origin software were employed for correlation analysis between color and chemical components. From raw to wine-processed Polygonati Rhizoma, the color of the samples darkened. Polysaccharide showed a decreasing trend, while extractum increased. The results of the HPLC fingerprint indicated significant chemical differences between raw and processed samples. Peaks were identified as 5-HMF (Peak 10), DDMP (Peak 12), and polygonatine A (Peak 17). By comparing the peak areas of 18 chromatographic peaks of the samples, it was revealed that from raw to processed samples, the peak areas of seven chromatographic peaks increased, one decreased, seven new components were newly generated, and three components disappeared. Based on OPLS-DA analysis of peak areas, the samples could be classified into two groups clearly; there were five chromatographic peaks with a VIP value greater than 1.0. The chromatographic peaks were numbered in order of their value as 7, 10, 17, 16, and 8; these five components were the main factors that distinguished raw and processed samples. Correlation analysis showed that the polysaccharides were positively correlated with L*, b*, and E_ab* but negatively correlated with a*. Extractum and Peaks 7, 8, 10, 16, and 17 were significantly negatively correlated with L*, b*, and E_ab* but positively correlated with a*. Regression analysis indicated that the contents of Peaks 7, 17, and 8, extractum, and polysaccharides could be predicted by combining the chromatic values with the regression equations, while the other components could not. This study showed that chromaticity could serve as an effective tool for predicting the component content of raw and wine-processed Polygonati Rhizoma. It will provide new ideas and methods for the identification and quality evaluation of different Polygonati Rhizoma processed products and offer a reference for standardizing traditional Chinese medicine processing techniques.