Biochemical components and fungal community dynamics during the flowering process of Moringa-Fu brick tea, a novel microbially fermented blended tea

Abstract

Moringa oleifera is a nutritious herb with a pronounced harsh taste. During microbial fermentation of Fu-brick tea, “flowering” promotes the oxidation, decomposition, and hydrolysis of biochemical components, resulting in a unique flavor. To improve the utilization and flavor of Moringa leaves, we developed a novel blended tea. Moringa-Fu brick tea via microbial fermentation and dark tea blending. We investigated chemical compositions and fungal community structures, and their possible correlations, during eight flowering stages using three blending ratios. Metabolic analysis showed that caffeine, theophylline, and gallic acid levels increased, whereas other key metabolite levels decreased after flowering. The genera Aspergillus, Saccharomycetales incertae sedis, and Candida predominated during the early flowering stage, but Eurotium dominated after 3 days with all three ratios. The fungal taxa were grouped into 14 modules, and six keystone taxa were identified. Three fungal genera (Saccharomycetales incertae sedis, Aspergillus, and Cyberlindnera) were the core functional genera linked to the metabolism of biochemical compounds. Supplementing 15% moringa tea with dark tea developed the best flavor, suggesting that this substrate's environment was more suitable for propagating dominant fungi and driving biotransformation. This study can serve as an exemplar for utilizing microbial-fermentation to improve the flavors of harsh-tasting plant resources.