Chemical Constitution and Antimicrobial Activity of Kombucha Fermented Beverage

Abstract

Kombucha is a traditional beverage of sweetened black tea fermented with a symbiotic association of acetic acid bacteria and yeasts. In this study, kombucha fermented beverage (KFB) appeared to include nine chemical groups (alcohols, acids, lactones, condensed heterocyclic compounds, antibiotics, esters, aldehydes, fatty acids, and alkaloids) of many bioactive metabolites, as elucidated by gas chromatography–mass spectrometry (GC-MS) and IR spectra. The fermented metabolic components of KFB seem collectively to act in a synergistic action giving rise to the antimicrobial activity. Four types of kombucha preparations (fermented, neutralized, heat-treated and unfermented) were demonstrated with respect to their antimicrobial activity against some pathogenic bacterial and fungal strains using agar well diffusion assay. KFB exerted the strongest antimicrobial activities when compared with neutralized and heat-treated kombucha beverages (NKB and HKB). Staphylococcus aureus ATCC6538 (S. aureus) and Escherichia coli ATCC11229 (E. coli) were the organisms most susceptible to the antimicrobial activity of kombucha beverage preparations. Finally, the KFB preparation showed remarkable inhibitory activity against S. aureus and E. coli bacteria in a brain heart infusion broth and in some Egyptian fruit juices (apple, guava, strawberry, and tomato). These data reveal that kombucha is not only a prophylactic agent, but also appears to be promising as a safe alternative biopreservative, offering protection against pathogenic bacteria and fungi.

Microbial Diversity and Characteristics of Kombucha as Revealed by Metagenomic and Physicochemical Analysis

“…Amongst these, Acetobacter, Bacillus, Starmerella and Komagataeibacter and Gluconobacter are the most prominent. These species form symbiosis with beneficial strains in the human gut and can inhibit the growth of infectious microorganisms [1,15]. Acetobacter produce by-products such as acetic and gluconic acid which are effective at inhibiting the growth of some common pathogenic bacteria that can cause the stomach upsets, sickness and diarrhoea associated with food poisoning.…”

“…Interestingly, the esters detected in FTIR analysis indicate increased yeast-induced production of esters. Apart from imparting flavour and aroma to kombucha, these ester groups also have an important role as antibacterial food additives by inhibiting bacterial growth [1]. Esters are hydrophobic in nature which allows the electrostatic interactions with the bacterial cell components resulting in loss of cell viability [45].…”

“…Kombucha has a long history throughout Asia and Europe as a fermented, naturally effervescent, drink that is reported to have multiple health enhancing effects. More recently in vitro and in vivo evidence suggest kombucha has health benefits that include, anti-microbial, antioxidant, detoxification, anti-tumour and immune-enhancing effects, along with enhancing gastrointestinal, hepatic cardiac and neurological function [1][2][3][4]. The microbial communities involved in the fermentation process produce a number of metabolites which make this tea beneficial to the human gut [5].…”

Kombucha Tea—A Double Power of Bioactive Compounds from Tea and Symbiotic Culture of Bacteria and Yeasts (SCOBY)

“…As a result, Kombucha may contribute to the reduction of health disorders such as cancer, cardiovascular diseases, and neurodegenerative diseases. In general, Kombuchas show positive effect on digestion and intestinal microbiota, relief against arthritis, possess antimicrobial activity, relief against hemorrhoids, detoxify body, show hepatoprotective effect, as well as reduce insomnia, relieve headaches, and positively impact a mood [7][8][9]. These activities results from (1) the presence of tea phenolic compounds; (2) phenolic compounds resulting from the metabolic activity of microorganisms (activity of enzymes hydrolyzing tea polyphenols); (3) the presence of organic acids produced by microorganisms; (4) the presence of vitamins from tea leaves or the product of microorganisms; (5) the presence of microbial enzymes and proteins, as well as (6) probiotic activities of microorganisms.…”

Modulation effects of microorganisms on tea in fermentation

“…In addition, black tea extracts fermented by acetic acid bacteria and yeast showed obvious inhibitory effects on Staphylococcus aureus ATCC6538 ( S. aureus ) and E. coli ATCC11229 ( E. coli ) ( 58 ), which suggest that fermented tea might be a potential source of preservatives. The antimicrobial activity of fu-brick tea after fermentation by bursa corundum is obviously improved compared with that without fermentation.…”