基于HS-SPME-GC-MS对不同等级双井绿茶香气物质的研究

Aroma Compounds of Different Grades Shuangjing Green Tea Based on HS-SPME-GC-MS

为探究不同等级双井绿茶香气物质组成特征,利用顶空固相微萃取-气相色谱-质谱联用技术(Headspace solid-phase micro extraction and gas chromatography mass spectrometry,HS-SPME-GC/MS)对修水县双井银毫、双井绿茶特级、双井绿茶一级和双井绿茶二级四个不同等级的双井绿茶的香气物质进行了检测分析。结果表明,从四个不同等级的双井绿茶中共鉴定出70种香气物质,主要包括醇类、烯烃类、烷烃类、酯类等化合物。不同等级的双井绿茶中香气物质组成及相对含量均有差异,通过主成分分析(Principal component analysis,PCA)和偏最小二乘法-判别分析(Partial least squares-discriminant analysis,PLS-DA),可以有效区分不同等级的双井绿茶。不同等级双井绿茶香气差异主要由反式-β-金合欢烯、香叶醇、水杨酸甲酯、茉莉酮、苯乙醇等14种关键化合物差异引起。在不同等级双井绿茶中关键香气物质表现出不同的分布规律,随着芽叶开展,α-椰油烯、石竹烯及己酸乙酯含量降低,而顺式-3-己烯醇、香叶醇及水杨酸甲酯含量呈增加趋势,芳樟醇、茉莉酮、反式-橙花叔醇含量从低到高,随后含量又迅速下降。本文研究了不同等级双井绿茶中香气物质的组成特征及关键香气物质的分布规律,为今后双井绿茶生产提供了理论依据。

To investigate the composition characteristics of aroma compounds in different grades of Shuangjing green tea,headspace solid-phase microextraction gas chromatography-mass spectrometry(HS-SPME-GC/MS)was used to detect and analyze aroma compounds in four different grades of Shuangjing green tea in Xiushui County.These grades included Shuangjing Yinhao,Shuangjing green tea super grade,Shuangjing green tea first grade,and Shuangjing green tea second grade. The results showed that a total of 70 aroma compounds were identified from four different grades of Shuangjing green tea. These compounds mainly included alcohols, olefins, alkanes, esters, and other compounds. The aroma components and relative contents of Shuangjing green tea varied among different grades. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) effectively distinguished between the different grades of Shuangjing green tea. The aroma changes of different grades of Shuangjing green tea were mainly caused by the relative changes in 14 key compounds, such as trans-β-farnesene, geraniol, methyl salicylate, (Z)-jasmone, phenylethyl alcohol, and so on. The key aroma compounds in different grades of Shuangjing green tea exhibited distinct distribution patterns. Accompanied by the development of buds and leaves, the contents of α-copaene, caryophyllene, and hexanoic acid ethyl ester decreased, whereas the contents of cis-3-hexen-1-ol, geraniol, and methyl salicylate showed an increasing trend. The linalool, (Z)-jasmone, and trans-nerolidol contents increased gradually. However, with the full development of the leaves, the contents of linalool, (Z)-jasmone, and trans-nerolidol decreased rapidly. In summary, this study examined the compositional characteristics of aroma compounds and the distribution patterns of key aroma compounds in four grades of Shuangjing green tea. These findings provide a theoretical basis for the future production of Shuangjing green tea.