Abstract:The microbial flora and fermentation methods affect the growth and metabolism of microorganisms during the fermentation of Pu-erh tea, which ultimately affects its fermentation quality. In this study, sensory evaluation, physicochemical analyses, amplicon high-throughput sequencing, and high-performance liquid chromatography-mass spectrometry were used to investigate the effects of hollow-fermentation on Pu-erh tea’s physicochemical parameters, microbial community structure and flavor. The results showed that there was no significant sensory difference between the hollow-fermented Pu-erh tea and traditional ground-fermented Pu-erh tea; and the microbial clustering of the two types of tea resembled. Compared with the traditional grounded-fermented Pu-erh tea, the species abundance of the eukaryotic microbiota in the hollow-fermented Pu-erh tea increased whilst the species abundance and diversity indices of its prokaryotic microbiota decreased significantly. For the hollow-fermented Pu-erh tea, the relative abundance of Rasamsonia (8.02%→32.29%) and Unclassified Micrococcaceae (8.51%→18.36%) increased significantly, whereas, the relative abundance of Aspergillus (46.03%→28.91%), Blastobotrys (10.14%→1.4%) and Bacillus (7.11%→0.60%) decreased. Meanwhile, the absolute values of pH (6.07→6.55), the contents of soluble polysaccharides (21.70→28.29 mg/g), theabrownin (86.41→109.43 mg/g), and caffeine (1.59→4.59) were significantly higher in hollow-fermented Pu-erh tea. The absolute contents of free amino acids (7.23→7.03 mg/g) and the relative contents of catechins (0.06→0.01) were significantly lower. Redundancy analysis showed that tea polyphenols and epicatechin gallate were significantly correlated with eukaryotic microbiota, while total flavonoids and epicatechin gallate were significantly correlated with prokaryotic microbiota. This study provides theoretical support for the improvement of traditional Pu-erh tea fermentation process.
