[Analysis of volatile component changes in wine-processing of Rhei Radix et Rhizoma based on headspace-gas chromatography-ion mobility spectrometry combined with chemometrics].

Based on volatile components, the dilution ratio of yellow rice wine to water in wine-processed Rhei Radix et Rhizoma was optimized, and the types and relative content changes of volatile components during the wine processing of Rhei Radix et Rhizoma were systematically investigated. Chemometrics combined with relative odor activity value(ROAV) was applied to further screen the key volatile components during the wine processing. Headspace-gas chromatography-ion mobility spectrometry(HS-GC-IMS) technology, along with VOCal 04.07 software and the Gallery Plot plugin, was employed to analyze the fingerprint and total ion intensity of samples prepared with different yellow rice wine dilution ratios. Preliminary screening results indicated that a dilution ratio of yellow rice wine to water of 1∶1 yielded the optimal outcome. Furthermore, based on HS-GC-IMS data, principal component analysis(PCA), partial least squares-discriminant analysis(PLS-DA), and variable importance in projection(VIP) analysis, combined with ROAV, were used to identify the key volatile components during the wine processing of Rhei Radix et Rhizoma. A total of 107 volatile components and their peak intensity information were detected. Through database matching, 81 components were identified, belonging to 12 categories of compounds. Among these, esters and sulfides account for a relatively high proportion, while phenols and ethers account for a relatively low proportion. During the processing, the peak intensities of hydrocarbons, acids, nitrogen-containing heterocycles, and nitrogen-sulfur compounds remained generally stable. The peak intensities of ketones and sulfides showed an initial increase followed by a decrease, whereas the peak intensity of esters exhibited a trend of first increasing, then decreasing, and subsequently increasing again. Although the changing trends of alcohols, oxygen-containing heterocycles, aldehydes, ethers, and phenols were not obvious, the peak intensities of alcohols and oxygen-containing heterocycles reached their highest levels at 12 min, while that of ethers was the lowest at 12 min. Through chemometric analysis and peak intensity changes, 29 volatile components with significant differences were screened, which effectively distinguished different processing stages of wine-processed Rhei Radix et Rhizoma, and 12 min was determined as the optimal processing endpoint. Combined with ROAV analysis, 2-methyl-3-furanthiol was ultimately identified as the key aroma component, while methyl isovalerate, 3-methyl-1-butanol, and butanal were identified as modifying components. In terms of volatile composition, a yellow rice wine to water of 1∶1 was found to be optimal. Esters and sulfur-containing compounds are the main volatile components of wine-processed Rhei Radix et Rhizoma, with 2-methyl-3-furanthiol serving as a key indicator for determining the optimal processing stage.