Determination of total phenolic content and antioxidant activity of the kombucha beverage derived from lemon balm, linden flowers, oak bark and caraway seeds

Kombucha is a fermented drink original made of Camellia sinensis L. tea sweetened with sugar, produced with symbiotic culture of bacteria and yeasts (SCOBY). Kombucha tea contains cultures of acetic acid bacteria, lactic acid bacteria and yeasts. Chemical assays of kombucha beverage have indicated various types of compounds, such as polyphenols, vitamins, organic acids, sugars, ethanol. The concentration of the compounds depends on fermentation conditions and raw material. Due to the wide range of bioactive compounds, kombucha might have a positive effect on the living organism [1]. The aim of this research was to evaluate total amount of phenolic compounds and antioxidant activity of kombucha prepared from dried lemon balm, linden flowers, oak bark and caraway seeds infusions. This work gains new knowledge on the use of different herbs, which have never been or insufficiently considered as a substrate for kombucha beverage. For this research fermentation was performed using kombucha drink as a starter culture, purchased from a local supermarket. All herbs infusions were sugared with sucrose and infused with broth containing kombucha culture. Black tea was used for comparison reason. Prepared infusions were left for 60 days in room temperature. Beverage pH were measured until the data stabilized. The total amount of phenolic compounds and antiradical activity were evaluated using spectrophotometric methods [2]. The highest quantity of phenolic compounds was found in lemon balm tea before fermentation 983.7±52.3 mg/L (expressed in rutin equivalents), while after fermentation it reduced to 417.1±22.2 mg/L, respectively. The highest antiradical activity was observed in black tea infusion 733.3±9.7 mg/L, while after fermentation it reduced to 320.97±3.16 mg/L. The pH of tested fermented drinks settled to 3.43-3.34 after 12 days of fermentation. The study found that total phenolic compounds content and [...]Gamtos mokslų fakultetasInstrumentinės analizės APCVytauto Didžiojo universiteta