Co-Fermentation with Lactiplantibacillus plantarum and Pichia pastoris: A Novel Approach to Enhance Flavor and Quality of Fermented Tea Beverage

Fermented tea beverage (FTB) has garnered significant attention owing to its unique combination of tea and wine flavors and its potential health benefits. This study investigates FTB co-fermented using different inoculum sizes of L. plantarum HYY-S10 and P. pastoris, evaluating physicochemical properties during the fermentation process. The final FTB products were comprehensively evaluated for their antioxidant activity, organic acid content, sensory characteristics, volatile flavor compounds, and microbial diversity. Compared with natural fermentation, the 1:1 mixed fermentation of these two microorganisms enhanced the antioxidant capacity and organic acid content of FTB. Furthermore, sensory evaluation revealed higher overall acceptability. Analysis of volatile compounds demonstrated an increase in the production of alcohols, esters, and ketones, leading to enhanced malty, fruity, and creamy aromas in FTB. Among these compounds, 3-methyl-1-butanol, phenylethyl alcohol, 1,2-propanediol, and 3-hydroxy-2-butanone play pivotal roles in shaping the flavor profile. High-throughput sequencing analysis identified Lactobacillus and Weizmannia as dominant bacteria, while Pichia or Issatchenkia was found to be dominant fungi. This study provides a theoretical foundation for the production of FTB through mixed fermentation with L. plantarum HYY-S10 and P. pastoris while contributing to the practical application of FTB production through mixed fermentation techniques. Collectively, our findings demonstrate that the 1:1 co-fermentation of L. plantarum HYY-S10 and P. pastoris is a promising strategy for developing novel fermented tea beverages with enhanced functional properties and complex, desirable flavors, offering valuable insights for the industrial production of specialty FTBs.