黑茶(DT)在中国拥有丰富的文化历史,并因其独特的风味和潜在的健康益处而获得了相当大的消费者。在这项研究中,顶空固相微萃取(HS-SPME)结合气相色谱-质谱(GC-MS),相对气味活性值(ROAV),用化学计量学方法检测和分析了不同地理区域的五种黑茶的香气成分差异。结果表明,来自不同地理区域的五个DT类型不同,数量,和挥发性化合物的相对浓度。HS-SPME-GC-MS在56个DT样品中鉴定出了1372种挥发性化合物。使用ROAV和化学计量学方法,基于ROAV>1和VIP>1。18种关键香气化合物可作为DT分类的潜在指标,包括二氢Actinidiolide,芳樟醇,1,2,3-三甲氧基苯,香叶基丙酮,1,2,4-三甲氧基苯,cedrol,3,7-二甲基-1,5,7-辛三烯-3-醇,β-紫罗兰酮,4-乙基-1,2-二甲氧基苯,水杨酸甲酯,α-紫罗兰酮,香叶醇,芳樟醇氧化物I,芳樟醇氧化物II,6-甲基-5-庚烯-2-酮,α-松油醇,1,2,3-三甲氧基-5-甲基苯,和1,2-二甲氧基苯。这些化合物为区分不同地理区域的5种DTs的差异提供了一定的理论依据。这项研究为鉴定DTs中的挥发性物质和阐明关键香气化合物的差异提供了一种潜在的方法。缩写:DT,黑茶;FZT,腐竹茶;LPT,广西六保茶;QZT,湖北青专茶;TBT,四川藏茶;PET,云南普洱茶;ROAV,相对气味活性值;OT,气味阈值;HS-SPME,顶空固相微萃取;GC-MS,气相色谱-质谱法;PCA,主成分分析;PLS-DA,偏最小二乘判别分析;HCA,层次聚类分析。
Dark tea (DT) holds a rich cultural history in China and has gained sizeable consumers due to its unique flavor and potential health benefits. In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS), relative odor activity value (ROAV), and chemometrics approaches were used to detect and analyze aroma compounds differences among five dark teas from different geographical regions. The results revealed that the five DTs from different geographical regions differed in types, quantities, and relative concentrations of volatile compounds. A total of 1372 volatile compounds of were identified in the 56 DT samples by HS-SPME-GC-MS. Using ROAV and chemometrics approaches, based on ROAV>1 and VIP>1. Eighteen key aroma compounds can be used as potential indicators for DT classification, including dihydroactinidiolide, linalool, 1,2,3-trimethoxybenzene, geranyl acetone, 1,2,4-trimethoxybenzene, cedrol, 3,7-dimethyl-1,5,7-octatrien-3-ol, β-ionone, 4-ethyl-1,2-dimethoxybenzene, methyl salicylate, α-ionone, geraniol, linalool oxide I, linalool oxide II, 6-methyl-5-hepten-2-one, α-terpineol, 1,2,3-trimethoxy-5-methylbenzene, and 1,2-dimethoxybenzene. These compounds provide a certain theoretical basis for distinguishing the differences in five DTs from different geographical regions. This study provides a potential method for identifying the volatile substances in DTs and elucidating the differences in key aroma compounds. Abbreviations: DT, dark tea; FZT, Fuzhuan tea; LPT, Guangxi Liupao tea; QZT, Hubei Qingzhuan tea; TBT, Sichuan Tibetan tea; PET, Yunnan Pu-erh tea; ROAV, Relative odor activity value; OT, Odor threshold; HS-SPME, Headspace solid-phase microextraction; GC-MS, Gas chromatography-mass spectrometry; PCA, Principal components analysis; PLS-DA, Partial least squares-discriminant analysis; HCA, Hierarchical clustering analysis.