Abstract: Six raw dark tea samples from the same batch were exposed to a high humidity environment to induce mildew. Besides, two naturally mildewed samples were collected from the market. The volatile components of all these samples were analyzed by simultaneous distillation extraction (SDE) combined with gas chromatography-mass spectrometry (GC-MS) and were evaluated based on the existing literature data on dark tea aroma. The results showed that a total of 23 volatile components were detected in all samples. A total of 38 and 43 volatile compounds were common to the artificially mildewed samples and the naturally mildewed ones, respectively. Palmitic acid, hexahydrofarnesyl acetone, isophytol, chlorophyllic acid, linoleic acid and methyl linolenate were the main volatile components of mildewed dark tea samples. The principal component analysis performed on the aroma components of mildewed dark tea showed that 1-octen- 3-ol, isophytol, phytol, 2,3-octanedione, octadecanoic acid, nonanal, longifolen, phthalic acid diisobutyl ester, β-cyclocitral, 2,6-dimethylcyclohexanol and linalol were highly positively correlated with the first principal component, which were responsible for the floral aroma with rancid and earthy odor and were related to the mildew flavor of sensory evaluation.

Key words: raw dark tea, mildew, volatile compounds