State Key Laboratory of Tea Plant Biology and Utilization, Key Laboratory of Food Nutrition and Safety, Anhui Engineering Laboratory for Agro-products Processing, School of Tea and Food Science & Technology, Anhui Agricultural University, Hefei 230036, China.
Food and Biological Engineering, Zhangzhou Institute of Technology, Zhangzhou 363000, China.
Food Chem. 2021 Jul 15;350:129234. doi: 10.1016/j.foodchem.2021.129234. Epub 2021 Feb 6.
The three instant dark teas were produced from instant green tea (IGT) by liquid-state fermentations using the microorganisms Eurotium cristatum (EFT), Aspergillus niger (AFT), and sequential inoculation of E. cristatum/A. niger (EAFT), respectively. The volatile compounds of four tea samples were extracted by headspace-solid phase microextraction (HS-SPME) and analyzed using gas chromatography-mass spectrometry (GC-MS) coupled with chemometrics. A total of 97 volatile compounds were tentatively identified to distinguish three fermented instant dark from IGT. Alcohols, acids, esters, ketones, aldehydes, and heterocyclics could be clearly distinguished by principal component analysis (PCA), venn diagram, heatmap analysis and hierarchical cluster analysis (HCA). Descriptive sensory analysis revealed that AFT had a moldy, woody and herbal aroma; EFT showed woody and herbal aroma; and EAFT smelled an herbal, sweet, minty and floral aroma. This study indicates that fermentation using different microorganisms is critical in forming unique aroma characteristics of instant dark teas.
三种速溶黑茶分别由速溶绿茶（IGT）通过液态发酵得到，使用的微生物分别为冠突散囊菌（EFT）、黑曲霉（AFT）和冠突散囊菌/黑曲霉顺序接种（EAFT）。通过顶空固相微萃取（HS-SPME）提取四个茶样中的挥发性化合物，并使用气相色谱-质谱联用（GC-MS）结合化学计量学进行分析。共鉴定出 97 种挥发性化合物，可区分三种发酵速溶黑茶和 IGT。通过主成分分析（PCA）、venn 图、热图分析和层次聚类分析（HCA）可以清楚地区分醇类、酸类、酯类、酮类、醛类和杂环类。描述性感官分析表明，AFT 具有发霉、木质和草药香气；EFT 表现出木质和草药香气；而 EAFT 则散发出草药、甜、薄荷和花香。本研究表明，使用不同微生物进行发酵对速溶黑茶独特香气特征的形成至关重要。
