A comprehensive review on microbiome, aromas and flavors, chemical composition, nutrition and future prospects of Fuzhuan brick tea

Background: Fuzhuan brick tea (FBT) as a representative type of dark tea is one of the three treasures of the ancient Silk Road in China together with Chinaware and Silk, and has become increasingly popular due to its unique flavors and health benefits. However, the knowledge of FBT is only scattered, and obviously, the more comprehensive study is requisite to reveal the relationship between consumption of FBT and human health, and further prospect the future of FBT-derived products. Scope and approach: A more comprehensive review to FBT was reported for the first time, and in this paper, microbiome, aromas and flavors, chemical ingredients and their compositions and nutrition, as well as the future prospects of developing FBT-derived products were reviewed and discussed. Key findings and conclusions: FBT contains a rich microbiome environment, where microbial genera represented by characteristic Eurotium cristatum, Debaryomyces, Aspergillus and Klebsiella may grow dynamically during the fermented manufacturing process. Under the actions of microorganisms and their metabolic enzymes, the content of all the major compounds significantly changed, leading to the production of unique aromas and flavors represented by ketones and alcohols, as well as the formation of indispensably new metabolic components with physiological activities. FBT and FBT-derived products owing to its nontoxicity and excellent bioactivities may service as functional food to protect human health and prevent chronic diseases. For the food industrial application, it is believed that the unique post-fermentation with complex mixed microbes mainly contributed by Eurotium cristatum may be conducive to microbial transformation and the formation of the functional compounds.