不同产地香茶的主要化学成分含量的差异分析

为了更加系统和全面地了解香茶的品质特征,分析比较来自浙江省松阳、遂昌和武义3个不同香茶主产地的香茶样品中的主要化学成分含量、氨基酸组成以及香气成分组成的差异。结果表明,不同产地的香茶样品中的茶多酚、游离氨基酸、咖啡碱、水浸出物、儿茶素总量及儿茶素单体含量等均无显著性差异(P0.05),而氨基酸组分中的天冬酰胺、脯氨酸和异亮氨酸在3个不同产地香茶中的质量分数存在显著性差异(P0.05)。在香茶中共鉴定出49种香气成分,以醇类化合物的种类和相对含量最高(共14种),其总量占所有香气成分的35.33%~46.19%。统计分析发现,香气成分中醇类、醛类和酮类相对含量在3个不同产地之间均存在显著性差异(P0.05)。基于香气成分的相对含量建立了偏最小二乘法判别分析模型(拟合参数为R2Y=0.832,Q2=0.625),成功区分3个产地的香茶样品;通过数据处理软件分析了香茶中的23种关键香气成分在3个不同产地中的分布规律。其中橄榄醇、1-辛烯-3-醇、反-2-辛烯醛、苯甲醛、2,3-环氧-β-紫罗酮、β-紫罗酮、α-紫罗酮、2-正戊基呋喃、反,反-2,4-庚二烯醛、3,5-辛二烯-2-酮、反,反-3,5-辛二烯-2-酮和2-乙基呋喃这12种香气成分主要在松阳香茶中的相对含量最高;β-芳樟醇、α-雪松醇、香叶醇、橙花醇、水杨酸甲酯和顺-3-己烯-苯甲酸酯在遂昌香茶中相对含量最高;而顺-β-罗勒烯、顺-己酸-3-己烯酯、顺-茉莉酮、吲哚和萘在武义香茶中相对含量最高。

Comparative Study on the Contents of the Major Chemical Constituents of Fragrant Tea from Different Producing Areas

In order to more systematically and fully understand the quality characteristics of fragrant tea, the major chemical constituents, amino acid composition and aroma compounds in fragrant tea obtained from three producing areas, i.e. Songyang county, Suichang county and Wuyi county in Zhejiang province, were analyzed and compared in this study. Results showed that the levels of the major chemical constituents including total polyphenols, total free amino acids, caffeine, water extracts, total catechins and catechin monomers were slightly different (P > 0.05) among different producing areas, whereas the levels of amino acids including asparagine, proline and isoleucine were found to be significantly different (P < 0.05). A total of 49 aroma components were detected, with alcohols being the most predominant, including 14 compounds (together accounting for 35.33% to 46.19% of the total aroma compounds. Statistical analysis showed that significant differences in the levels of alcohols, aldehydes and ketones were observed among different areas (P < 0.05). Moreover, fragrant tea samples from three different areas were distinguished successfully using partial least squares discriminant analysis model (R2Y = 0.832 and Q2 = 0.625) which was established based on the relative contents of aroma components. The distribution of 23 key aroma components among different areas was analyzed by a data processing software. The 12 most abundant aroma compounds identified in Songyang area included maali alcohol, 1-octen-3-ol, (E)-2-octenal, benzaldehyde, 2,3-epoxy-β-ionone, β-ionone, α-ionone, 2-pentylfuran, trans,trans-2,4-heptadienal, 3,5-octadien-2-one, trans,trans-3,5-octadien-2-one and 2-ethylfuran, β-linalool, α-cedrol, geraniol, nerol, methyl salicylate and Z-3-hexenyl benzoate were the most abundant aroma compounds in Suichang tea, and cis-β-ocimene, cis-3-hexenyl hexanoate, cis-jasmone, indole and naphthalene were found to be the most abundant in Wuyi area.