3个产地不同等级庐山云雾茶挥发性成分主成分分析

Principal Component Analysis of Volatile Compounds in Different Grades of Lu Mountain Clouds-Mist Tea from Three Regions

以顶空固相微萃取法结合气相色谱-质谱联用技术对3个产地不同等级庐山云雾茶挥发性物质进行测定。结果在所有样本中共鉴定出76种挥发性成分。利用主成分分析方法寻找影响不同等级庐山云雾茶挥发性成分的主要因子。结果表明,通远镇庐山云雾茶提取了4?个主成分累计方差贡献率达到80.4%;赛阳镇庐山云雾茶提取了3?个主成分累计方差贡献率达到87.9%;星子县庐山云雾茶提取了3?个主成分累计方差贡献率达到89.8%,得分图中不同等级庐山云雾茶能通过各自的化学特征被完全区分开。结合载荷图中变量重要性因子大于1的挥发性成分,寻找出不同等级特征香气物质。结果表明,等级越高价格越贵的庐山云雾茶,如己醛、顺-3-己烯-1-醇、正己醇、庚醛、苯甲醛、2-正戊基呋喃、柠檬烯、异佛尔酮、芳樟醇、茉莉酮等呈香挥发性物质的相对含量就越高。本实验为研究庐山云雾茶的等级区分提供了一种新的思路。

The volatile compounds of different grades of Lu Mountain Clouds-Mist Tea from three regions（Tongyuan township, Saiyang township, and Xingzi county） were investigated by solid phase micro extraction（SPME） followed by gas chromatography-mass spectrometry（GC-MS）. A total of 76 of volatile components were identified. Principal component analysis was applied to find out the main factors affecting the volatile components in different grades of Lu Mountain Clouds-Mist Tea. The results showed that the first 4, 3 and 3 principal components contributed cumulatively to 80.4%, 87.9%and 89.8% of the total variation for the teas from Tongyuan, Saiyang and Xingzi, respectively. Different grades of tea could be discriminated by their respective chemical properties. The volatile compounds with variable importance in the projection（VIP） value greater than 1 in the loading plots were screened for the characteristic aroma compounds in different grades of tea. The results showed that the higher grade and more expensive Lu Mountain Clouds-Mist tea had higher contents of aroma compounds, such as hexanal,（Z）-3-hexen-1-ol, hexanol, heptanal, benzaldehyde, 2-pentyl-furan, limonene, isophorone, linalool, and jasmone. This study provides a new idea for grade discrimination of Lu Mountain Clouds-Mist Tea.