城步峒茶红茶加工过程中香气物质的动态变化

罗娟; 沈瑜; 肖力争

doi:10.13386/j.issn1002-0306.2025090178

城步峒茶红茶加工过程中香气物质的动态变化

Dynamic Changes in Aroma Components of Camellia sinensis var. assamica cv. Duntsa Black Tea during Processing

摘要

摘要: 为探究城步峒茶红茶的关键香气物质和在加工过程中的形成规律。本研究采用顶空固相微萃取-气相色谱-质谱联用技术（Headspace-solid phase microextraction-gas chromatography-mass spectrometry，HS-SPME-GC-MS），系统分析了鲜叶（XY）、摇青（YQ)、萎凋（WD）、揉捻（RN）、发酵（FJ）、初烘（CH）和成品（CP）七个加工过程样的挥发性物质变化。并进行了主成分分析（Principal component analysis，PCA）与正交偏最小二乘判别分析（orthogonal partial least squares-discrimination analysis，OPLS-DA）及其置换检验，最后通过相对香气活度值（relative odor activity value，rOAV）、香气特征影响（Aroma character impact，ACI）筛选出关键香气成分。结果表明，城步峒茶红茶加工过程中的茶样共鉴定出107种挥发性物质，以醇类、酯类、烯烃类为主，整个加工过程中，醇类、酯类、其他类物质的相对含量总体呈波动下降趋势；醛类、酮类、烯烃类物质的相对含量则呈现波动上升的趋势，基于香气物质的相对含量建立的PCA和OPLS-DA模型可有效区分不同加工过程的茶样；进一步以VIP>1、rOAV>1且ACI>1%为筛选条件，确定芳樟醇、水杨酸甲酯、香叶醇、己酸己酯、反式-橙花叔醇等五种物质共同构成了城步峒茶红茶花果甜香型的香气品质。芳樟醇、香叶醇、己酸己酯的相对含量呈现先上升后下降的趋势，于揉捻阶段达到最高，分别为382.74、123.32和35.43 mg/L，反式-橙花叔醇其相对含量呈现波动增加的趋势，增幅为22.60%，水杨酸甲酯相对含量呈现波动下降的趋势，揉捻阶段含量达到最高点，为252.95 mg/L。本研究结果可为城步峒茶红茶香气品质解析提供一定理论参考依据。

Abstract: In order to investigate the key aroma compounds of Camellia sinensis var. assamica cv. Duntsa black tea and their formation mechanism during processing, this study utilized headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) to systematically analyze the volatiles in fresh leaves (XY), shaking (YQ), withering (WD), rolling (RN), fermentation (FJ), initial drying (CH), and finished product (CP). Principal component analysis (PCA) and orthogonal partial least squares-discrimination analysis (OPLS-DA) with permutation tests were performed. Key aroma compounds were identified using relative odor activity value (rOAV) and aroma character impact (ACI). Results revealed that during the processing, 107 volatile compounds were identified in the tea samples of Camellia sinensis var. assamica cv. Duntsa black tea primarily comprising alcohols, esters, and alkenes. During the whole processing process, the relative content of alcohols, esters and others showed a fluctuating downward trend. The relative content of aldehydes, ketones and olefins showed a fluctuating upward trend. The PCA and OPLS-DA models based on the relative content of aroma substances could effectively distinguish different processing samples. Further screening, with VIP>1, rOAV>1 and ACI>1% as the conditions determined that linalool, methyl salicylate, geraniol, hexyl hexanoate, trans-nerolidol and other five components together constitute the aroma quality of the sweet type of Camellia sinensis var. assamica cv. Duntsa black tea. The relative content of linalool, geraniol, and hexyl hexanoate showed an initial increase followed by a decline, peaking during the rolling stage at382.74, 123.32, and 35.43 mg/L respectively. The relative content of trans-nerolidol showed a fluctuating upward trend, increasing by 22.60%. The relative content of methyl salicylate showed a fluctuating decrease, peaking at 252.95 mg/L during the rolling stage. The results of this study can provide a theoretical reference for the analysis of the aroma quality of Camellia sinensis var. assamica cv. Duntsa black tea.