Effects of Nixing Pottery Storage on Microbial Community Characteristics, Quality, and Volatile Components of Liupao Tea

Liupao tea tended to suffer from unbalanced microbial community structure during storage, which further caused quality deterioration of tea, resulting in economic losses and potential food safety risks. Nixing Pottery (NP) exhibited remarkable advantages in the storage and fresh keeping of tea. Taking glass containers (GC) as the control group, this study investigated the effects of NP on the infusion color, non-volatile internal components, volatile aromatic components, and microbial community structure of Liupao tea during a 24-month storage period. The results indicated that Liupao tea stored in NP showed significant differences compared with that stored in GC. Compared with the tea stored in GC, Liupao tea preserved in NP for 24 months exhibited a reddish-brown appearance with higher brightness, and the degradation rates of non-volatile substances, such as water extracts, free amino acids, and tea polyphenols, were relatively slower. A total of 128 volatile compounds were detected by GC-MS, among which 34 were differential volatile compounds, and these compounds collectively led to the flavor differences between Liupao tea stored in NP and GC. High-throughput sequencing results revealed that Firmicutes and Proteobacteria maintained stable dominant positions for a long time in the NP storage system. Correlation analysis suggested statistical associations between microorganisms, including Firmicutes and Eurotiales, and the transformation of major chemical components in Liupao tea. This study laid a theoretical foundation for the storage and fresh keeping of Liupao tea, the industrial promotion of NP, and the development of new natural mineral-based packaging materials for fermented tea.