Wang Qiushuang, Qin Dandan, Jiang Xiaohui, Fang Kaixing, Li Bo, Wang Qing, Pan Chendong, Ni Erdong, Li Hongjian, Chen Dong, Wu Hualing
Tea Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of Tea Plant Resources Innovation and Utilization, Guangzhou 510640, China.
Foods. 2023 Apr 6;12(7):1560. doi: 10.3390/foods12071560.
Guangdong black teas have diverse flavors and aromas. To explore the molecular basis of these aromas, we extracted and analyzed the volatile flavor compounds of 31 black tea samples from 7 districts (Yingde, Luokeng, Renhua, Meizhou, Chaozhou, Lianshan, and Heyuan) in Guangdong Province with headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Then, 135 volatile flavor compounds (VFCs) were identified and grouped into 12 classes according to their chemical structure. Notably, alcohols accounted for 31.40-44.43% of total VFCs. The score plot of supervised partial least squares-discriminant analysis (PLS-DA) revealed good discrimination for most black tea samples. Additionally, 64 compounds with variable importance in projection > 1.0 were identified as differential odorants. Through an odor activity value analysis, eight volatile compounds were identified as the key active differential VFCs: linalool, methyl salicylate, phenylethyl alcohol, -cresol, 3-methyl-butanoic acid, geraniol, benzaldehyde, and benzeneacetaldehyde. Thus, benzeneacetaldehyde and linalool in YJ-Yingde samples, benzaldehyde in Luokeng samples with an almond-like aroma, phenylethyl alcohol in the Heyuan samples, and -cresol and 3-methyl-butanoic acid in the Chaozhou samples were the key volatile flavor compounds that could differentiate local black teas from other black teas. These findings will enrich the research in tea aroma chemistry and provide a method for identifying the origins of Guangdong black teas.
广东红茶具有多样的风味和香气。为探究这些香气的分子基础，我们采用顶空固相微萃取（HS-SPME）结合气相色谱-质谱联用（GC-MS）技术，提取并分析了来自广东省7个地区（英德、罗坑、仁化、梅州、潮州、连山和河源）的31个红茶样品中的挥发性风味化合物。随后，鉴定出135种挥发性风味化合物（VFCs），并根据其化学结构分为12类。值得注意的是，醇类占总VFCs的31.40 - 44.43%。监督偏最小二乘判别分析（PLS-DA）的得分图显示，对大多数红茶样品有良好的区分效果。此外，64种投影变量重要性>1.0的化合物被鉴定为差异气味物质。通过气味活性值分析，8种挥发性化合物被确定为关键活性差异VFCs：芳樟醇、水杨酸甲酯、苯乙醇、间甲酚、3-甲基丁酸、香叶醇、苯甲醛和苯乙醛。因此，英德样品中的苯乙醛和芳樟醇、具有杏仁样香气的罗坑样品中的苯甲醛、河源样品中的苯乙醇以及潮州样品中的间甲酚和3-甲基丁酸是能够区分本地红茶与其他红茶的关键挥发性风味化合物。这些发现将丰富茶叶香气化学的研究，并为鉴定广东红茶的产地提供一种方法。
