基于电子鼻和气相色谱-离子迁移谱法分析不同等级俄色绿茶香气物质差异

Analysis of the difference of volatile compounds in different grades of E’se green tea based on electronic nose and gas chromatography-ion mobility spectrometry

中文关键词:  俄色绿茶  电子鼻  气相色谱-离子迁移谱法  香气物质  质量鉴别

英文关键词:E’se green tea  electronic nose  gas chromatography-ion mobility spectrometry  aroma substances  quality identification

中文摘要:

      目的 研究不同等级俄色绿茶香气成分的组成及差异。方法 采用电子鼻和气相色谱-离子迁移谱法(gas chromatography-ion mobility spectrometry, GC-IMS)对极品(LCJP)、特级(LCTJ)、一级(LCYJ)俄色绿茶的香气物质进行检测, 并利用主成分分析(principal component analysis, PCA)法及正交偏最小二乘法判别分析(orthogonal partial least squares discriminant analysis, OPLS-DA)模型评价识别3种不同等级俄色绿茶间的香气差异。结果 电子鼻和GC-IMS分析结果均表明3种等级茶叶香气特征有显著差别, 其中LCYJ与LCTJ风格相似, 而LCJP风格独特。GC-IMS在3种茶样中共检测出39种挥发性成分, 主要为酯类、醛类、酮类、醇类物质; OPLS-DA模型筛选得到25个变量重要性投影值(variable importance in the projection, VIP)大于1的特征物质, 乙醇、月桂烯在LCJP样本中含量最低, 是引起LCJP茶汤香气清淡风味的主要原因之一。结论 利用电子鼻结合GC-IMS可实现俄色绿茶不同质量等级的有效甄别, 对俄色绿茶的质量化评估具有重要意义, 同时该研究可为后续俄色茶资源的开发利用提供一定理论依据

英文摘要:

      Objective To study the composition and difference of aroma components in different grades of E’se green tea. Methods Electronic nose and gas chromatography-ion mobility spectrometry (GC-IMS) were used to detect the volatile compounds of best quality (LCJP), premium (LCTJ), and first grade (LCYJ) E’se green tea, and principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) model were used to evaluate and identify the aroma differences among the 3 different grades of E’se green tea. Results The results of electronic nose and GC-IMS analysis showed that there were significant differences in the aroma characteristics of the 3 grades of tea. LCYJ had similar style with LCTJ, while LCJP had unique style. A total of 39 volatile components were detected by GC-IMS in 3 kinds of tea samples, mainly including esters, aldehydes, ketones and alcohols. A total of 25 characteristic substances with variable importance in the projection (VIP) greater than 1 were screened out by OPLS-DA model. And the content of ethyl alcohol and myrcene were the lowest in LCJP samples, which was one of the main reasons for the mild flavor of LCJP tea infusion. Conclusion Using electronic nose combined with GC-IMS technology can realize the effectively screening of different quality grades of E’se green tea, which is of great significance to the quality evaluation of E’se green tea. Meanwhile, this study can provide a theoretical basis for the subsequent development and utilization of E’se green tea resources.