Amount of Eurotium sp. in Chinese Liupao tea and its relationship with tea quality

Abstract

Objective Eurotium sp. are the sexual states of the genus Aspergillus, and their ascospore is a spherical closed capsule with a golden colour. The growth of Eurotium sp. during tea production is a key step in achieving the unique quality of dark tea. This study aimed to evaluate the relationship between Eurotium sp. amount and Liupao tea quality. Methods and Results The amounts of Eurotium sp. in 26 differently aged Liupao tea samples from several factories were studied. Indicators related to the quality of Liupao tea were investigated. The amounts of Eurotium sp. were divided into 0, 105 and 106 levels, and quantitative real‐time polymerase chain reaction (qPCR) was performed. Using ultrahigh‐performance liquid chromatography and high‐performance liquid chromatography, the amounts of emodin and physcion were determined to be closely related to the amount of Eurotium sp. Emodin was not found or occurred in minimal amounts in all raw Liupao tea samples. By contrast, physcion was found in Liupao tea at the 106 level of Eurotium sp. Liupao tea samples with varying levels of Eurotium sp. also exhibited evident differences in aroma and chromaticity. Result of the Pearson correlation test showed that the amount of Eurotium sp. plays a key role in creating the unique quality of Liupao tea. Conclusion The amount of Eurotium sp. in dark tea detected via qPCR can be used as a quantitative quality indicator for evaluating dark tea. Significance and Impact of the Study The present study provides an efficient method for identifying the different qualities of dark tea and addressing quality control issues in fermenting dark tea.

Discrimination and characterization of the volatile profiles of five Fu brick teas from different manufacturing regions by using HS–SPME/GC–MS and HS–GC–IMS

“…These esters were dominated by methyl salicylate and ethyl acetate. Methyl salicylate imparts the aroma of wintergreen oil and mint and has been reported to be one of the key VOCs contributing to the characteristic flavor of FBT samples ( Li et al, 2020a , 2020b ). Notably, organic acids were present at low levels in all FBT samples.…”

Comparison of the Fungal Community, Chemical Composition, Antioxidant Activity, and Taste Characteristics of Fu Brick Tea in Different Regions of China

“…For instance, Zhao et al reported that Aspergillus produced a variety of enzymes (pectinesterase, endo-1,4-β-xylanase, catalases, catalase-peroxidases, alkaline protease, and peroxiredoxins) that contributed to the oxidation of tea polyphenols and degradation of plant cell wall ( 30 ). Furthermore, the genus Aspergillus make great contribution to the enhancement of taste by secreting enzymes like proteases, α-amylases glucoamylases, xylanases, and other hemicellulose to decompose complex carbohydrates, proteins and lipid into small molecules in FBT and produce unique flavor ( 31 , 32 ). Besides, it was found that Saccharomycopsis and Debaryomyces were more abundant in the ZJ sample than that in other regions, and Monascus and Wallemia were the two genera that only existed in the ZJ sample.…”

Multiplex PCR Identification of Aspergillus cristatus and Aspergillus chevalieri in Liupao Tea Based on Orphan Genes

“…It was found that the amount of Eurotium sp. plays a vital role in developing the unique quality of Liupao tea [ 46 ]. As described by Li [ 47 ], Aspergillus can change the volatile profiles of Liupao tea.…”