基于HS-SPME/GC-MS/O分析滇绿茶特征香气物质

The Analysis of Characteristic Aroma Compounds in Dian Green Tea by Application of HS-SPME/GC-MS/O

采用顶空固相微萃取结合气相色谱-质谱/嗅闻(HS-SPME/GC-MS/O)技术,对滇绿茶的香气物质进行定性、相对定量以及感官分析。将26个茶样根据产地分为四组,通过绿茶传统感官审评和香气定量描述性分析(QDA)筛选出3个品质突出的滇绿茶样品。HS-SPME/GC-MS/O分析结果表明:在上述3个样品中共鉴定出83种挥发性成分,总相对含量为10.694%,主要为醛、酮和芳香族化合物,对应的主要香气物质有22种。综合仪器分析和感官评价结果得出,香气强度最高的化合物有2,3-辛二酮(奶香)、月桂烯(柑橘香/花香)、(E,E)-2,4-庚二烯醛(花香)、苯甲醛(杏仁味)、芳樟醇(柑橘香/花香)、二氢芳樟醇(柠檬味/甜香)、香叶醇(玫瑰香/柑橘味)、柠檬烯(柑橘味)、香叶基丙酮(青草味)、二甲基硫醚(玉米香)、3-甲基丁醛(麦芽香)、6-甲基-5-庚烯-2-酮(爆米花香/烘烤香)、别罗勒烯(罗勒草香)、己醇(青草味/杏仁味)、水杨酸甲酯(清凉/薄荷味)、β-大马士酮(煮苹果味)、茉莉酮(花香)和β-紫罗兰酮(花香),上述化合物为滇绿茶特征香气成分。该研究为滇绿茶香气品质提升和工艺改进提供了理论基础。

Dian green tea,a kind of green tea made from fresh leaves of large leaf tea variety in Yun⁃nan province,present unique aroma quality.However,its characteristic aroma compounds were un⁃clear.Headspace solid phase microextraction combing with gas chromatography-mass spectrometry/olfactometry(HS-SPME/GC-MS/O)was applied for the identification,quantitation,and sensory analysis of the aroma components of Dian green tea.26 samples were divided into 4 groups according to their origins.Based on the traditional green tea sensory evaluation and quantitative descriptive analysis(QDA),three Dian green tea samples with high quality were selected.The results of HSSPME/GC-MS/O showed that a total of 83 odorants were identified in S3,S6,S15 tea infusions,and the total relative content was 10.694%.Among which,aldehydes,ketones,and aromatic com⁃pounds were the main constituents.Twenty-two corresponding major aroma compounds were found.Among the 43 aroma substances with higher content(>0.05%),alcohols,aldehydes,ketones,and esters commonly present pleasure odor notes,and play a direct role in the formation of aroma quality of Dian green tea.Alcohols mainly evoked an alluring flowery and fruity aroma.Aldehydes were closely related to the formation of tea aroma and various specific aroma characteristics,and their relative contents were high in Dian green tea.Aromatic aldehydes such as benzaldehyde mainly present almond-like note,while many kinds of aliphatic aldehyde were found and they mainly showed freshy and flowery odor.Most of the esters had a strong fruity flavor.However,methyl salicylate,a common odorant in tea,had the strong freshy perception.It contributed to the aroma quality of Dian green tea significantly.Ketones were another main aroma component in Dian green tea,and their aroma characteristics were closely related to their structures.It is worth mentioning that although low contents in Dian green tea,some aroma substances such asβ-damasone and(E)-4-heptenal evokes obvious aroma in low concentrations because of their low odor thresholds in water.According to the re⁃sults of the instrumental and sensory analysis,compounds present highest aroma intensities were 2,3-octanedione(milk-like),laurene(citrus-like/flowery),(E,E)-2,4-heptadienal(flowery),benzaldehyde(almond-like),linalool(citrus-like/flowery),hotrienol(lemon-like/sweety),geraniol(rose-like/citrus-like),limonene(citrus-like),geranylacetone(grassy),methyl sulfide(corn-like),3-methylbutanal(malty),6-methyl-5-hepten-2-one(popcorn-like/roasty),(4E,6Z)-alloocimene(basil-like),1-hexanol(grassy/almond-like),methyl salicylate(fresh,mint-like),β-damascenone(cooked apple-like),jasmonone(flowery),andβ-ionone(flowery).The above mentioned com⁃pounds were regarded as key odorants of Dian green tea.The study characterized the key aroma com⁃pounds of Dian green tea,which provides the theoretical basis for aroma quality and process improve⁃ment of Dian green tea.