Kombucha beverages made from Camellia nitidissima Chi and Camellia sinensis flowers—physicochemical properties, sensory properties and bioactivity

Recently, various plant materials other than tea have been used as substrates for kombucha beverages. To improve the aroma and other qualities of kombucha, Camellia sinensis and Camellia nitidissima Chi flowers were used as raw materials to prepare novel kombucha beverages (marked as TFK and GFTK), which were systematically compared to traditional kombucha made from black tea. The results revealed that the biomass of kombucha made from TFK increased the most among all samples. TFK had the highest content of organic acids, with 9.03 g/L of acetic acid and 5.57 g/L of gluconic acid. Metabolomic analysis revealed that TFK showed the highest concentration of organic nitrogen compounds, whereas GFTK had the highest concentration of flavonoids. There were 183 kinds of volatile components identified in the 3 kombuchas, only 20 of which were common aroma components. Among the three kombucha beverages, TFK had the highest digestive enzyme inhibitory activity and was also second only to GFTK in terms of anti-oxidant properties. In terms of sensory properties, TFK had a higher fruit score compared to GFTK, but there was no significant difference in floral intensity between these two samples. Therefore, the C. sinensis flower is more suitable for preparing kombucha.