Study on dynamic changes in characteristic volatile compounds uncovers aroma development of Hainan Dayezhong (Camellia sinensis var. assamica) black tea.

To elucidate the characteristic aroma of Hainan Dayezhong black tea, GC-MS, GC-olfactometry, and electronic nose analyses were used to examine the changes in volatile compounds. A total of 527 volatiles were identified and quantified, of which 80 compounds with relative odor activity values exceeding 1 in dried tea samples were selected as biomarkers. Floral and sweet-associated volatiles, including damascenone, benzaldehyde, and linalool, were proposed to be responsible for the characteristic aroma. Our results indicated that multiple stresses occurring during withering, rolling, and fermentation contributed to the distinctive floral aroma, while the thermal effects of drying enhanced sweet odors by volatilizing certain fragrant compounds, thereby improving the final quality of the dried tea. These findings provide a foundation for quality control in practical manufacturing and will contribute to the development of standard operating procedures for producing Hainan Dayezhong black tea with desirable aromas.