This study aimed to develop a functional fermented tea beverage utilising Wuyi Rock Tea (WRT) stalks. Fermentation parameters were optimized using response surface methodology, yielding the following optimal conditions: tea stalks, 9 g/L; white sugar, 104 g/L; and dual-strain inoculum, 8%. The resulting product achieved a sensory score of 84.7 and a total phenolic content of 519.13 mg gallic acid equivalents (GAE)/L. It exhibited strong antioxidant, hypoglycemic, and hypolipidemic activities, with a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging rate of approximately 90 %, an α-glucosidase inhibition rate of 83.55 %, and a binding rate of approximately 68 %. Metagenomic analysis revealed that Gluconobacter oxydans dominated the early and late fermentation stages, whereas Starmerella bacillaris prevailed during the mid-stage. Efficient carbohydrate and amino acid metabolism by G. oxydans and S. bacillaris facilitated the synthesis and transformation of functional components. These findings provide a promising strategy for the high-value utilization of tea processing by-products.
Yang et al. (Thu,) studied this question.