Digital evaluation of tea aroma intensity and odor characteristics changes during processing

Abstract Background Huangjingui ( Camellia sinensis )，a kind of oolong tea, is native to Anxi County, Fujian Province, China, and is a national tea tree species. Tea processing is the key link in the formation of its aroma characteristics, and it is important to analyze the influence of each processing process on the aroma intensity and odor characteristics of tea, in order to optimize the tea processing process and improve the quality of tea. Results The processing process favored the accumulation of volatile compounds in oolong tea, as evidenced by the increase in their content from 9.793 to 123.052 μg/kg, of which the highest content was mainly in terpenoids, alcohols and esters substances. The aroma formation of oolong tea was mainly composed of 14 key compounds, among which the most critical compounds were four substances such as geraniol, α‐pinene, methyl salicylate and trans‐β‐ionone. The typical odor characteristics of oolong tea were floral and wood, among which the formation of floral odor mainly came from geraniol and methyl salicylate, and the formation of wood odor characteristics mainly came from α‐pinene and trans‐β‐ionone. Further analysis showed that the aroma quality of oolong tea could be improved by focusing on key processes such as fermentation and kneading during the processing of oolong tea. Conclusion The processing was conducive to the accumulation of aroma compounds of oolong tea, improving the aroma intensity of tea leaves and forming the unique floral and wood odor characteristics of oolong tea.