Abstract: To investigate the aroma characteristics and dynamic changes of volatile compounds of Dahongpao at different charcoal baking times, quantitative descriptive analysis (QDA), headspace solid-phase microextraction (HS-SPME) and comprehensive two-dimensional gas chromatography-quadrupole time-of-flight mass spectrometry (GC×GC-Q-TOF/MS) were applied to analyze the volatile compounds at different charcoal baking times of 200 min, 300 min, 400 min, 500 min and 600 min (LF200, LF300, LF400, LF500 and LF600). The results show that the grassy aroma appeared in the early stage of charcoal baking, and with the extension of charcoal baking time, the grassy aroma gradually disappeared, and the floral and fruity aroma were prominent, and the floral and fruity aroma were the most porminent in the LF600 sample. A total of 304 volatile compounds were detected in Dahongpao at different charcoal baking times, among which alcohols, aldehydes and esters were the main ones. The principal component analysis (PCA) and hierarchical cluster analysis (HCA) results divided the samples under different carbon baking times into three groups, and 11 major differential compounds were screened by variable important for the projection (VIP)>1 and relative odor activity value (ROAV)>1. Among them, the relative content of (E,E)-2,4-hexadienal in the grassy characteristic decreased with the extension of the charcoal baking time, while the relative contents of methyl benzoate, methyl phenylacetate, nerolidol and myrcene in the fruity characteristics increased with the extension of the charcoal baking time. The purpose of this study was to regulate the quality of Dahongpao, and to improve the drinking attributes for the subsequent production and processing of Dahongpao.

Key words: Dahongpao, baking times, aroma characteristics, volatile components