Influence of Eurotium cristatum and Aspergillus niger individual and collaborative inoculation on volatile profile in liquid-state fermentation of instant dark teas
Qi Chen a,1 , Mingyue Zhang a,1 , Mengxue Chen a , Mengru Li a ,Haiwei Zhang a , Pengpeng Song a , Tingting An a , Pengxiang Yue b , Xueling Gao a,*
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 sampleswere 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 in dicates that fermentation using different microorganisms is critical in forming unique aroma characteristics of instant dark teas.
KEYWORDS: Instant dark tea 、Eurotium cristatum 、Aspergillus niger 、Liquid-state fermentation 、Volatile components 、Sensory analysis