title: Antioxidant and Antibacterial Activity of the Beverage Obtained by Fermentation of Sweetened Lemon Balm (Melissa officinalisL.) Tea with Symbiotic Consortium  of Bacteria and Yeasts.
abstract: Kombucha is a fermented tea beverage which is traditionally prepared by fermenting sweetened black or green tea (Camellia sinensisL.) with symbiotic consortium of bacteria and yeasts (SCOBY). In this study, lemon balm (Melissa officinalisL.) was used as the only nitrogen source for kombucha fermentation. During the seven-day fermentation process, pH value, titratable acidity (TA), total phenolic content, phenolic compounds, and antioxidant activity against hydroxyl (˙OH) and 1,1-diphenyl-2-picrylhydrazil (DPPH) radicals were measured to detect the connection between the fermentation time and antioxidant and antibacterial activities of lemon balm kombucha. Antibacterial activity of finished beverages with optimum acidity (TA=4-4.5 g/L), the value which is confirmed by long-time kombucha consumers, and enhanced acidity (TA=8.12 g/L) was tested against eleven wild bacterial strains. The results showed that lemon balm could be successfully used as an alternative toC. sinensisL. for kombucha fermentation. Total phenolic content and antioxidant activity against DPPH radicals of lemon balm fermentation broth were higher than those of traditional kombucha. Rosmarinic acid is the main phenolic compound of the lemon balm-based kombucha that probably provides biological activity of the beverage. Judging from the EC50values, kombucha beverages exhibited higher antioxidant activities compared withC. sinensisL. andM. officinalisL. infusions, which can probably be ascribed to SCOBY metabolites. Lemon balm kombucha with both optimum and enhanced acidity showed antibacterial activity, which can be primarily ascribed to acetic acid, but also to some other tea components and SCOBY metabolites.
authors.affiliation: Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, RS-21000 Novi Sad, Serbia.
authors.forename: Aleksandra S
authors.initials: AS
authors.lastname: Velićanski
authors.affiliation: Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, RS-21000 Novi Sad, Serbia.
authors.forename: Dragoljub D
authors.initials: DD
authors.lastname: Cvetković
authors.affiliation: Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, RS-21000 Novi Sad, Serbia.
authors.forename: Siniša L
authors.initials: SL
authors.lastname: Markov
authors.affiliation: Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, RS-21000 Novi Sad, Serbia.
authors.forename: Vesna T Tumbas
authors.initials: VT
authors.lastname: Šaponjac
authors.affiliation: Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, RS-21000 Novi Sad, Serbia.
authors.forename: Jelena J
authors.initials: JJ
authors.lastname: Vulić
keywords: antibacterial activity; antioxidant activity; kombucha; lemon balm tea