基于HS-SPME-GC-O/MS方法分析新、陈大红袍中的关键差异性香气活性成分

Analysis of Key Differential Aroma-Active Components in New and Aged Dahongpao Oolong Teas Based on HS-SPME-GC-O/MS Technology

香气是评价茶叶品质的重要因素之一。为系统解析新、陈大红袍中香气成分差异,从而为大红袍的科学储藏提供参考依据,本研究采用顶空固相微萃取-气相色谱质谱联用法(HS-SPME-GC-MS)和气相色谱-嗅觉测量法(GC-O)从新大红袍和陈年大红袍中共鉴定出185种香气成分和45种香气活性化合物。偏最小二乘法判别分析和非参数检验结果表明:31种关键香气化合物在新、陈两组大红袍样品之间存在统计学差异(P<0.05)。通过化合物峰面积与香气强度值对新、陈大红袍中的关键差异香气化合物和香气活性化合物进行对比分析,结果表明:2-乙酰基呋喃、3,5-二甲基-2-乙基-吡嗪、芳樟醇、苯乙醇、乙酸苯乙酯、吲哚和己酸己酯等7种化合物的峰面积与香气强度值呈现一致的变化趋势,说明它们对于区分新、陈年大红袍香气有重要贡献。因此,这些化合物是区分新、陈大红袍的关键差异性香气活性成分,具有作为判别陈年武夷岩茶的化学标志物的潜在应用前景。本研究结果为大红袍香气的科学评价和“新陈茶”的判别提供了技术参考。

Aroma is one of the most important factors to evaluate the quality of tea.In order to systematically analyze the difference of aroma components in new and aged Dahongpao oolong teas,and thus provided a scientific basis for storing Dahongpao teas,headspace-solid-phase microextraction combined with gas chromatography-mass spectrometry(HS-SPME-GC-MS)and gas chromatography-olfactometry(GC-O)were mainly used in this study.A total of 185 aroma compounds were identified from new Dahongpao and aged Dahongpao oolong teas by HS-SPME-GC-MS,and 45 aroma-active components were identified by using GC-O method.Partial least squares discriminant analysis(PLS-DA)and non parametric test indicated that there were 31 key aroma compounds with statistical differences between the two groups(P<0.05).Whereafter,the key aroma compounds with statistical differences and aroma-active components in new and aged Dahongpao were further investigated by combining the peak areas and aroma intensity(AI).Results showed that the peak areas of 2-acetylfuran,3,5-dimethyl-2-ethylpyrazine,linalool,phenylethyl alcohol,phenethyl acetate,indole and hexyl hexanoate had the same trend as those of aroma intensity.Therefore,these key differential aroma-active components have important contribution for distinguishing the aroma between the new and aged Dahongpao oolong teas,which present a potential applications in the identification of aged Wuyi rock teas.The results of this study provide some technical references for the scientific evaluation of Dahongpao aroma and the discrimination of"new and aged"teas.