Background: Taiping houkui tea won the title of “the King of Green Tea” at the International Tea Exposition in 2004, which had an orchid fragrance but the material basis of the orchid fragrance had not been revealed yet. Objective: To investigate the material basis of the orchid fragrance and identify the quality grade of Taiping houkui tea. Methods: A method was developed for evaluating orchid-like aroma between different grades Taiping houkui tea by solid-phase micro extraction (SPME) and comprehensive two-dimensional gas chromatography coupled with time-of-fight mass spectrometry (GC×GC-TOFMS). The crushed tea sample in a 25 mL headspace bottle was incubated at 90°C for 10 min. Then the gaseous sample was extracted by SPME divinylbenzene/polydimethylsiloxane fiber for 50 min and thermally desorpted at 250°C for 2 min. Results: In total, 735 volatile compounds were determined by SPME- GC×GC-TOFMS and 15 compounds were related to orchid-like aroma. Conclusions: The high-quality Taiping houkui tea has the orchid fragrance and the low-grade one does not; thus orchid-like aroma can be used as a reference of grades of Taiping houkui tea. Highlights: Thirty different grades of Taiping houkui tea samples were compared and analyzed experimentally, and the results showed that the special aroma substances, which played a key role in grade discrimination of Taiping houkui tea, were found by the statistical method.

中文翻译：

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固相微萃取-综合二维气相色谱-战斗时间质谱法评估不同品位太平厚魁茶之间的兰花样香气

背景：太平猴魁茶在2004年国际茶展上荣获“绿茶之王”的称号，该茶虽然具有兰花香气，但其物质基础尚未透露。目的：探讨兰花香的物质基础，确定太平厚魁茶的质量等级。方法：建立了固相微萃取（SPME）和二维气相色谱-飞行时间质谱（GC×GC-TOFMS）相结合的评价太平厚魁茶不同品系兰花样香气的方法。将25毫升顶空瓶中的压碎茶样品在90°C下孵育10分钟。然后将气态样品用SPME二乙烯基苯/聚二甲基硅氧烷纤维萃取50分钟，并在250°C下热脱附2分钟。结果：用SPME-GC×GC-TOFMS测定了735种挥发性化合物，其中15种与兰花样香气有关。结论：优质太平侯奎茶有兰花香，低档无香。因此，类似兰花的香气可以作为太平厚魁茶品位的参考。重点：通过实验比较和分析了三十种不同等级的太平厚朴茶样品，结果表明，采用统计方法发现了特殊的香气物质，这些物质在太平厚朴茶的等级鉴别中起着关键作用。