Understanding Kombucha Tea Fermentation: A Review

Kombucha is a beverage of probable Manchurian origins obtained from fermented tea by a microbial consortium composed of several bacteria and yeasts. This mixed consortium forms a powerful symbiosis capable of inhibiting the growth of potentially contaminating bacteria. The fermentation process also leads to the formation of a polymeric cellulose pellicle due to the activity of certain strains of Acetobacter sp. The tea fermentation process by the microbial consortium was able to show an increase in certain biological activities which have been already studied; however, little information is available on the characterization of its active components and their evolution during fermentation. Studies have also reported that the use of infusions from other plants may be a promising alternative

Evolution of Polyphenols during Syrah Grapes Maceration: Time versus Temperature Effect

The effect of maceration time and temperature on the phenolic compounds of Syrah grape musts was studied. Pre-fermentation cold (10 °C) and heat maceration (60, 70 and 80 °C) were applied and compared to traditional maceration (control, 25 °C). The macerations were monitored and the kinetic profile of the maceration was studied by taking samples at 0, 2, 4, 8, 24 and 48 h. The results showed that heat treatment had the most significant effect on the extraction of total polyphenol. A significant loss of anthocyanin content was observed when the maceration was extended beyond eight hours at high temperatures, while longer maceration times seemed to favor the extraction of tannins. A principal component analysis showed that independently of the vinification technique, and for the same grape varieties, different winegrowing regions and harvest years affected the phenolic composition of the grape ski

Analysis of the impact of fining agents types, oenological tannins and mannoproteins and their concentrations on the phenolic composition of red wine

This paper aimed to evaluate and analyze the effect of five fining agents, commercial tannins and mannoproteins on the pigment, color and tannins composition of a Cabernet Sauvignon red wine. The wines were analyzed 2 d after treatment and immediately after separation of sedimentation. Color was evaluated by spectrophotometry and polyphenols were analyzed by spectrophotometry and HPLC-DAD. The results showed that all treatments affected the phenolic contents of the wine. The most remarkable effects on phenolic composition were produced by bentonite and Polyvinylpolypyrrolidone (PvPP) + potassium caseinate which significantly decreased anthocyanins and tannins concentrations, respectively. The use of vegetable protein and gelatin has a less impact on the color and phenolic contents of red wines. The antioxidant activity was little affected by treatments except the addition of tannins that increased it. Principal components analysis demonstrates the importance of a low concentration of agents for high total polyphenol levels

Synthesis and evaluation of chromone-2-carboxamide derivatives as cytotoxic agents and 5-lipoxygenase inhibitors

In the present study, we prepared a series of 21 chromone carboxamide derivatives bearing diverse amide side chains. Their potency to inhibit the proliferation of breast (MCF-7), ovarian (OVCAR and IGROV), and colon (HCT-116) cancer cell lines, was evaluated in vitro using the MTT assay. Among these compounds, 13 showed promising cytotoxic activity against at least one cancer cell line with IC50 in the range 0.9–10 μM. Our compounds were also screened for their anti-inflammatory activity as putative inhibitors of 5-lipoxygenase. Structure-activity relationships studies on our chromone carboxamide derivatives revealed that the presence of a 6-fluoro substituent on the chromone nucleus (R1) or propyl and 3-ethylphenyl groups on the amide side chain (R2) has a positive impact on the cytotoxic activity. In terms of the anti-inflammatory activity, hydrophilic chromone carboxamide derivatives showed greater 5-lipoxygenase inhibition. The physico-chemical properties of chromone carboxamides are in accordance with the general requirements of drug development process and ligand efficiency values allow further structure optimization, with compound 4b as a lead

Impact of fermentation conditions on the production of bioactive compounds with anticancer, anti-inflammatory and antioxidant properties in kombucha tea extracts

The production of natural bioactive compounds through the fermentation of plants has increased in recent years. The biological activities of the extracts obtained from the fermentation of black tea with the kombucha consortium were evaluated. To improve the productivity of these compounds two different vessel geometries were used and successive extractions with solvents of increasing polarity were performed. Forty-seven compounds were identified by GC–MS, including several organic acids and phenolic compounds. Total phenolic content, pH value, and antioxidant, antiproliferation and anti-inflammatory activities were measured after 21 days of fermentation. A higher surface/height (s/h) ratio seemed to enhance the anti-inflammatory activity of kombucha tea, resulting in IC50 value of 9.0 ± 0.1 μg/mL compared to 24.3 ± 0.2 μg/mL with the lowest ratio. Regarding the anticancer activity, the highest inhibition percentage of 55.3% at 50 μg/mL against the HCT-116 human colon carcinoma cell line was obtained with the ethyl acetate extract after 21 days of fermentation compared to the value of 8% obtained with the same extraction solvent using the non-fermented black tea. These results showed that fermentation may improve the biological activities of the tea and that the production of bioactive compounds can vary depending on the fermentation condition

Antioxidant activity of phenolic acids and esters present in red wine on human Low-Density Lipoproteins

To evaluate the antioxidant activity of different phenolic acids and their esters, three types of experiments have been used. Electron paramagnetic resonance (EPR) quantitative analysis was carried out using the acetaldehyde/xanthine oxidase system and Fenton's reaction to generate superoxide and hydroxyl radicals, respectively. In a second test, hydroperoxides generated by Cu2+-catalysed oxidation of low density lipoproteins (LDL) were quantified by a modified iodometric method. In a third assay, LDL were oxidized with Esterbauer's method and modified LDL species were quantified by HPLC. The results show that the esterified phenolic derivatives present a better antioxidant activity, on the lipoperoxidation of LDL, than the corresponding phenolic acids

Metabolome-microbiome signatures in the fermented beverage, Kombucha

Kombucha is a fermented tea. Here we investigate the fermentation kinetics, metabolite production, microbiome and potential health promoting properties of three different kombucha consortia. Shotgun metagenomic sequencing revealed several dominant bacterial genera such as Komagataeibacter, Gluconacetobacter and Gluconobacter. Brettanomyces and Schizosaccharomyces were the most dominant yeasts identified. Species distribution reflected different patterns of sugar consumption, with S. pombe being present in samples with the highest sugar conversion. Liquid-liquid extractions were performed with organic solvents in order to obtain dried extracts, which were later characterized. HPLC-DAD and GC-MS analysis revealed differences in the production of organic acids, sugars, alcohols and phenolic compounds, where the presence of caffeine, propanoic acid and 2,3 butanediol differ greatly across the three kombuchas. Metabolomic analysis exhibited a link between the microbiota and the production of bioactive compounds in kombucha fermentation. In vitro assays were carried out in order to evaluate potential health-promoting features of the fermented teas, with notable outcomes including antioxidant ability against DPPH radical and against the 15-lipoxygenase enzyme, indicating a potential anti-inflammatory activity. These investigations considerably enhance our understanding of the relationship between the microbiota and metabolites as well as health promoting potential of kombucha and have the potential for the development of future generations of kombucha products in which these relationships are optimized

Radical trapping properties of imidazolyl nitrones

The ability of ten imidazolyl nitrones to directly scavenge free radicals (R√) generated in polar (√OH, cysteinyl, √CH3) or in apolar (CH3–√CH–CH3) media has been studied. When oxygen or sulfur-centered radicals are generated in polar media, EPR spectra are not or weakly observed with simple spectral features. Strong line intensities and more complicated spectra are observed with the isopropyl radical generated in an apolar medium. Intermediate results are obtained with √CH3 generated in a polar medium. EPR demonstrates the ability of these nitrones to trap radicals to the nitrone C(α) atom (alpha radical adduct) and to the imidazol C(5) atom (5-radical adduct). Beside the nucleophilic addition of the radical to the C(α) atom, the EPR studies suggest a two-step mechanism for the overall reaction of R√ attacking the imidazol core. The two steps seem to occur very fast with the √OH radical obtained in a polar medium and slower with the isopropyl radical prepared in benzene. In conclusion, imidazolyl nitrones present a high capacity to trap and stabilize carbon-centered radicals

Physicochemical properties of bacterial cellulose obtained from different Kombucha fermentation conditions

The production of bacterial cellulose has been limited due to its high cost and low productivity. Alternative low‐cost sources of this biopolymer of high purity and biocompatibility are needed in order to benefit from its enormous potential. Kombucha tea is a trend functional beverage whose production is growing exponentially worldwide, and the bacteria present in this fermented beverage belonging to the genus Komagataeibacter are capable of producing a crystalline biofilm with interesting properties. Obtaining bacterial cellulose from Kombucha tea has already been studied, however several fermentation conditions are being optimized in order to scale‐up its production. In this study, we characterized the bacterial cellulose produced from three different Kombucha fermentation conditions. The scanning electron microscopy images revealed the crystalline structure of the biofilms. The energy‐dispersive x‐ray analysis exhibited the chemical composition of the crystals. The thermogravimetric analysis showed a rate of degradation between 490 and 560°C and the differential scanning calorimetry confirmed the presence of crystalline and amorphous regions in the bacterial cellulose samples. The results suggested that crystalline cellulose could be obtained by varying the fermentation conditions of Kombucha tea

Synthese, proprietes physicochimiques, et activites pharmacologiques de complexes antitumoraux derives du platine(II), relations structure-activite

SIGLEINIST T 74039 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc