(R)-Linalool is a key indicator of aroma quality levels of a distinctive black tea (Camellia sinensis var. Yinghong No. 9)

Camellia sinensis var. assamica is a major variety used to produce black tea. However, the core compounds influencing its aroma quality are unknown. In this study, Yinghong No. 9 black tea (YJBT), a distinctive black tea in South China, was analyzed. We detected 44 aroma compounds and identified seven key contributors, namely linalool, geraniol, trans -linalool oxide (furanoid), hexanal, methyl jasmonate, phenylacetaldehyde, and β-ionone. Linalool, which was generally more abundant in spring tea than in summer tea, contributed significantly to sweet and floral aromas. ( R )-Linalool was the primary linalool form in Yinghong No. 9, wherein it was highly abundant in high-quality tea leaves. The substantial expression of a linalool synthase gene and the relatively high catalytic efficiency of the encoded enzyme likely contributed to the accumulation of ( R )-linalool. This study identified the primary aroma compounds in YJBT, providing a foundation for advancing our knowledge of the aromatic quality of black tea.