Differences in Key Flavor Substances and Quality between Charcoal-Baked and Electrically Baked White Tea

In this study, the differences in the aroma substances, major flavor substances and sensory quality of different grades of charcoal-baked and electrically baked white tea were studied by gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC) combined with chemometrics methods. The results showed that a total of 262 volatile compounds were detected, with terpenes, heterocyclic compounds, alcohols, esters and ketones being the major components, and 2-phenyl ethanol, linalool, geraniol, methyl salicylate, laurene, and (E)-linalool oxide accounting for a higher proportion of the total amount of volatile compounds. Compared with electrically baked white tea, 77, 16 and 93 differential volatile substances were identified from charcoal-baked Yinzhen, Baimudan and Shoumei tea, respectively. Odor activity value (OAV) analysis showed that linallinol, geraniol, 2-phenyl ethanol and laurene were important aroma substances of charcoal-baked white tea, which contribute to natural refreshing, floral and fruity or sweet aromas. Analysis of non-volatile compounds showed that there were significant differences in the content of total and individual catechins, tea polyphenols, caffeine and water extract between charcoal-baked and electrically baked white tea. The results of sensory evaluation were consistent with those of volatile and non-volatile substances. This study is helpful to understand the aroma and flavor quality of charcoal-baked white tea and provides theoretical support for improving the quality of white tea.