Identification of the different aroma compounds between conventional and freeze dried wuyi rock tea (Dangui) using headspace solid phase microextraction

Abstract

Wuyi rock tea, a kind of semi-fermented Oolong tea, is produced around Wuyi Mountain. Due to its unique aroma and taste, namely the aroma of flowers and the earthy taste of rocks (hence its name as Wuyi rock tea), it has become very popular in China. Its characteristics are associated with the manufacturing processes. During which many compounds are produced. Nonvolatile compounds contribute to the taste, while volatile compounds contribute to the aroma. In this study, volatile compounds from two samples using different drying methods were extracted using headspace-solid phase microextraction (HSSPME) approach, and then analyzed, compared and identified with gas chromatography-mass spectrometry (GC-MS). Among the volatile compounds, trans-nerolidol, farnescene, hexyl hexanoate, indole and geraniol were identified, and found to have high content in both samples. The analytical results showed that freeze drying process is an alternative drying method, which is especially suitable for the production of highly scented Wuyi rock tea.