The relationship between bacterial dynamics, phenols and antioxidant capability during compressed white tea storage

The quality and efficacy of compressed white tea (CWT) can be affected by the bacterial community during its long-term storage. However, it is not clear how bacteria affect the CWT storage process. In this study, 16S rDNA was used to identify the composition and dynamic changes of bacterial community during CWT storage, and chemometrics methods were used to evaluate the relationship between the bacterial community and phenol/ antioxidant indices. A total of 31 bacterial phyla and 764 bacterial genera were identified during CWT storage, and their diversity decreased significantly at first and then increased significantly (P < 0.05). The 10th year of storage was the key period for changes in bacterial diversity and dominant phyla and genera. The prediction of phenotype and function revealed that these changes were dominated by aerobic bacteria, which could involved in 264 metabolic pathways, including flavonoids metabolism. Chemometric analysis verified that seven core functional bacteria promoted the decline of eight phenols during CWT storage, thus reducing antioxidant capability. In conclusion, this study reveals that the bacteria in CWT affect its antioxidant capability by altering the phenol content during storage. In addition, 29 biomarkers during CWT storage were screened, which accumulated uniquely in different storage years.

Automated summary

In this study, the composition and dynamic changes of the bacterial community during the long-term storage of compressed white tea (CWT) were investigated. The results showed that the bacterial diversity initially decreased and then increased significantly during CWT storage. The dominant phyla and genera of bacteria changed significantly in the 10th year, which was also the key period for alterations in antioxidant capability. The study further revealed that aerobic bacteria played a dominant role in these changes and influenced the phenol content, thus affecting the antioxidant ability of CWT. Additionally, 29 biomarkers unique to different storage years were identified during the study.