Amount of Eurotium spp. in Chinese Liupao Tea and Its Relationship with Tea Quality.
J Appl Microbiol. 2020 Jan 23;:
Authors: Li Z, Huang L, Xia N, Teng J, Wei B, Peng D
OBJECTIVE: Eurotium spp. are the sexual states of the genus Aspergillus, and their ascospore is a spherical closed capsule with a golden color. The growth of Eurotium spp. during tea production is a key step in achieving the unique quality of dark tea. This study aimed to evaluate the relationship between Eurotium spp. amount and Liupao tea quality.
METHOD AND RESULTS: The amounts of Eurotium spp. 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 spp. 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 spp. 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 spp. Liupao tea samples with varying levels of Eurotium spp. also exhibited evident differences in aroma and chromaticity. Result of the Pearson correlation test showed that the amount of Eurotium spp. plays a key role in creating the unique quality of Liupao tea.
CONCLUSION: The amount of Eurotium spp. 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.
PMID: 31975478 [PubMed – as supplied by publisher]