Abstract
Chinese post-fermented teas are produced through special fermentation by microorganisms, with fungi significantly contributing to their flavor and sensory characteristics. Here, the fungal community structure and function were investigated using Illumina HiSeq sequencing of the fungal ITS rDNA region across different post-fermented teas, including Fuzhuan, Qingzhuan, Tianjian black, Liupao, and raw and ripened Pu-erh. Additionally, the headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) technology was used to compare the volatile components of tea samples, and moisture content, pH, total nitrogen, carbon-nitrogen ratio, and total sulfur were measured. All the tea samples were slightly acidic, with pH values of 5.56-6.43, and Ascomycota was the most dominant phylum, representing over 90% of the relative abundance. However, there were significant differences at the genus level in the six typical post-fermented teas. Aspergillus was the most dominant genus in Fuzhuan (91.16%), Qingzhuan (54.89%), Tianjian (64.11%), and Liupao (47.43%) teas, whereas Debaryomyces and Blastobotrys were the most dominant genera in raw (35.67%) and ripened (78.88%) Pu-erh tea, respectively. A functional prediction analysis revealed that most fungal gene functions were involved in metabolism. A total of 26 main volatile components were detected, which differed in composition among six tea samples. This is the first comparative analysis of fungal communities and volatile components in different typical Chinese post-fermented teas, and the results will aid the design of better culturing strategies for the specific dominant fungal species and the influence of fungi on aroma types of post-fermented teas.