基于HS-SPME/GC×GC-TOFMS/OAV不同栗香特征绿茶关键香气组分分析

采用顶空固相微萃取结合全二维气相色谱-飞行时间质谱技术分析3类典型栗香绿茶的挥发性成分,并采用香气活度值(odor activity value,OAV)法对关键香气组分进行筛选。结果表明:3类不同栗香特征的绿茶共鉴定出79种共有香气组分,其中萜烯类较多,醛类物质相对含量最高;基于OAV不小于1,共筛选出12种关键香气组分,其中己醛、1-辛烯-3-酮、β-紫罗兰酮在3类典型栗香绿茶中OAV均不小于10,特别是1-辛烯-3-酮在3类典型栗香绿茶中OAV均超过100;以OAV结果为基础,在模拟体系中添加相同浓度和比例的关键香气组分进行香气重构,3类典型栗香重构样与对照样的夹角余弦值均在0.97以上。本研究明确了12种关键香气组分对栗香绿茶特征香气的贡献作用,并通过香气重组实验进一步证实了结果的可靠性,为绿茶赋香物的定性及量化理论研究提供了一定的理论依据。

Analysis of Key Odorants Responsible for Different Chestnut-Like Aromas of Green Teas Based on Headspace Solid-Phase Microextraction Coupled with Comprehensive Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry and Odor Activity Value

The volatile components of green tea samples with three different typical chestnut-like aromas were investigated using headspace solid phase microextraction(HS-SPME)combined with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry(GC×GC-TOFMS).The key odorants responsible for chestnut-like aroma were identified based on their odor activity values(OAV).The results showed that a total of 79 compounds were identified as common components among the three chestnut-like aromas,the majority of which were terpenes,while aldehydes showed the highest content.Moreover,12 compounds with OAV≥1 were identified as the key odorants responsible for the chestnut-like aromas,among which hexanal,1-octen-3-one and trans-β-ionone exhibited higher OAV(≥10).Notably,1-octen-3-one showed the highest OAV(>100)in all three chestnut-like aroma types.In addition,based on the OAV results,the key aroma components added at the same concentrations and ratios to the simulation system for aroma reconstitution.The cosine values of reconstituted samples and standard references for the three typical chestnut-like aromas were all above 0.97.The contribution of 12 key aroma components to the characteristic aroma of chestnut-like green teas were preliminarily confirmed,and the reliability was further confirmed by aroma reconstitution experiments.The results provide theoretical support for qualitatively and quantitatively evaluating green tea aroma compounds.