Rapid profiling of volatile compounds in green teas using Micro-Chamber/Thermal Extractor combined with thermal desorption coupled to gas chromatography-mass spectrometry followed by multivariate statistical analysis

In the present work, a simple, rapid and reliable method using Micro-Chamber/Thermal Extractor (μ-CTE) combined with thermal desorption (TD) coupled to gas chromatography-mass spectrometry (TD-GC-MS) was developed for investigating the differences in aroma determinants among three chestnut flavor green teas (tender chestnut, chestnut, and cooked chestnut). The extraction parameters such as sample amount, extraction time, and chamber temperature were evaluated through orthogonal experimental design to achieve the maximum of extraction efficiency. Subsequently, the repeatability and precision of the method were confirmed under optimal conditions. A total of 97 volatile compounds were identified in 15 green tea samples. Furthermore, multivariate statistical analysis including partial least square-discrimination analysis (PLS-DA) and hierarchical clustering analysis (HCA) were conducted to reveal the detailed distinctions of three chestnut flavor green teas. Totally, 41 potential volatile markers were identified based on variable importance in projection (VIP) score > 1, which were responsible for the discrimination of green teas with three different flavor characteristics. The results suggest that the proposed strategy is a feasible and rapid technique to distinguish green teas and will provide scientific role on the special flavor quality assessment of green teas.