Characterization of aroma differences on three drying treatments in Rucheng Baimao (Camellia pubescens) white tea

Abstract

Rucheng Baimao (Camellia pubescens) is an excellent raw material for manufacturing white tea. Drying is the last step in white tea processing and is essential for white tea's aroma. In this study, aroma sensory evaluation combined with volatile compound analysis reveals the characteristic aroma differences of Rucheng Baimao white tea with oven drying (OD), air drying (AD), and sun drying (SD) treatments. Sensory results showed that OD samples had a stronger floral and grassy aroma, AD samples exhibited a more pronounced fresh and pekoe aroma, and SD samples exhibited a unique sunshine odor. Thirty compounds were screened as differential aroma-active compounds of the aroma difference of Rucheng Baimao white tea with three drying treatments using multivariate statistical analysis and relative odor activity value (ROAV ≥1) analysis. The weighted correlation network analysis of the differential compounds revealed the potential association between volatiles and aroma. The results showed that 17 compounds (such as hexanal and p-cymene) were significantly positively correlated with the grassy aroma and 21 compounds (such as linalool and benzeneacetaldehyde) were significantly positively correlated with the floral aroma. Most of these compounds were abundant in OD samples, contributed to its aroma characteristics.