Impact of Kombucha Fermentation on the Flavor and Physicochemical Properties of Tea (Camellia sinensis) Flower Infusions

Abstract

Tea (Camellia sinensis) flower is a nutritious and affordable raw material for beverages. However, the taste of infusions brewed directly from tea flowers with hot water is not very appealing. In the work, the effects of kombucha fermentation on the sensory quality and chemical profiles of tea flower infusions were investigated. During the 5-day fermentation experiment, the samples fermented for 1 day exhibited the best overall flavor characteristics. The flavor of this sample was significantly improved, with a marked increase in sweet aromas and a noticeable enhancement of fruity, sweet, and sour tastes. PacBio sequencing revealed that four Komagataeibacter spp. (88.64%), Novacetimonas hansenii (7.09%), and Zygosaccharomyces bisporus (97.55%) were the dominant bacterial and fungal species in the used Kombucha. A total of 80 volatiles were detected in all samples, and relative odor activity value (ROAV) analysis showed that alpha-ionone, linalool, beta-ionone, decanal, and 1-octen-3-ol were the major contributors to the aroma perception. The pH value and the contents of caffeine, total catechins, amino acids, and proteins decreased, while the contents of total soluble sugars and 21 compounds including sugar derivatives, organic acids, and cyclic adenosine monophosphate (c-AMP) significantly increased. These results provided new insights into the development of tea flower-based kombucha beverage.