Comparative Analysis on Aromatic Components of Sun-dried Green Tea from Different Townships in Menghai County

In this paper, sensory evaluation, electronic nose and gas chromatography mass spectrometry (GC-MS) were used to analyze the main aromatic components and differences of sun-dried green tea in different townships of Menghai County. Sensory evaluation showed that the main aroma types of sun-dried green tea in townships were different, with fruit aroma in the Bulang Mountain, green aroma in Xiding, woody aroma in Meng'a and Mengzhe, floral aroma in Mengman, Gelang and Mengsong. The results of electronic nose showed that the aroma of sun-dried green tea in different townships was significantly different, and W1S, W1W, W2S and W2W sensors played a major role in distinguishing. In PCA analysis, the Bulang Mountain and Meng'a Mingxian were different from other townships. A total of 77 volatile substances were detected in sun-dried green tea from 7 townships by GC-MS, mainly including olefins, alkanes and alcohols, the most abundant being linalool, d-limonene, cedrol, limonene, α-cedrene. The result of Clustering thermogram showed that the general similarity of volatile substances in Gelanghe, the Bulang Mountain, Mengsong, Mengman and Xiding was the highest, and the difference between Meng'a, Mengzhe and other towns was the largest. There were 38 components with aroma description could be divided into three types: fruit aroma, flower aroma and woody aroma(green). The total relative content of volatile matter of each aroma type varied greatly in different townships. The highest total relative content of volatile matter of fruit aroma, flower aroma and woody aroma (green) types were the Bulang Mountain, Mengman and Mengzhe respectively. 2~3 kinds of special aromatic components could be found in the sun-dried green tea in other townships except Mengsong. Among them, the Bulang Mountain had safranal and naphthalene, Mengman had benzaldehyded and 1, 2, 4-trimethylbenzene, Meng'a had p-cymene and (-)-α-pinene, Gelanghe had 4-carene, cyclohexanol and α-pinene, Mengzhe had (S)-(-)-α-terpineol, (R)-camphor, and cedrene, Xiding had α-ocimene. The comprehensive analysis showed that there were great differences in sensory evaluation and volatile aroma types, types and relative content of the aroma of sun-dried green tea in different townships of Menghai, showed distinctive aroma quality characteristics.