By: Nutrition Expert- Vidula Kozarekar, Mumbai.
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Kombucha is the name of the beverage obtained from the fermentation of tea, mainly black tea (there are also other varieties that can be used as a base for its preparation, such as green and oolong tea, also known as blue tea); with added sugar as a substrate for fermentation. Although this beverage has originally been prepared using tea, it is possible to find variations made with infusions like mint, lemon balm or jasmine (1).
This beverage is made by fermenting sugared tea using a symbiotic culture of bacteria and yeasts. Kombucha consumption has been associated with some health effects such as: the reduction of cholesterol levels and blood pressure, reduction of cancer propagation, the improvement of liver, the immune system, and gastrointestinal functions. The beneficial effects of Kombucha are attributed to the presence of bioactive compounds that act synergistically (1).
The taste of the beverage is slightly acidic and slightly carbonated, which provides greater acceptance among consumers. Some metabolic products of Symbiotic Culture of Bacteria and Yeast (SCOBY), like acetic acid and other organic acids, possess antibacterial activity and prevents contamination of the drink by pathogenic bacteria.
The typical method of preparation of the Kombucha beverages using sugared black tea: (2)
- Multipurpose Tea
Kombucha beverage is known to possess many prophylactic and therapeutic benefits; it is believed to help in digestion, give relief against arthritis, act as a laxative, prevent microbial infections, combat stress and cancer, provide relief against haemorrhoids, impart a positive influence on the cholesterol levels, and facilitate excretion of toxin as well as blood cleansing (3), (4), (5).
Reduction of menstrual disorders and menopausal hot flashes, improving eye sight, cellular regeneration, and stimulation of glandular systems in the body, relieving bronchitis and asthma and the enhancement of general metabolism are a few more of the health benefits which have been claimed to be associated with consumption of the Kombucha broth (4).
- Probiotic Effect
This beverage is also associated with influencing the gastrointestinal microbial flora in humans by acting as a probiotic drink and helping in balancing the intestinal flora, thus facilitating the normalization of intestinal activities to a certain extent (3), (6), (7).
- Good for Hair, Skin & Nail
It is also known to have the ability to improve the health of hair, skin, and nails, reduce stress and nervous disturbances, reduce insomnia, relieve headaches, reduce the craving for alcohol of an alcoholic person, and prevent the formation of bladder infections (4), (5).
- Kidney Health
Reducing the kidney calcification is also known to be a beneficial effect of this beverage (4).
- Higher Anti-Oxidant Capacity than Regular Black Tea
The microbial community has the ability to enhance the radical scavenging activity of black tea by the fermentation process; showing a higher antioxidant capacity than black tea (5), (8).
Home brewing Kombucha: (9)
- In small-scale and home brewing, Kombucha is typically made in glass jars topped with fabric. Black or green tea leaves are steeped in hot water with sugar, then removed.
- When the sweetened tea has cooled, it is mixed with white vinegar or a bit of Kombucha from a previous batch to make the liquid more acidic.
- A gelatinous mat of symbiotic culture of bacteria and yeast (SCOBY) is then added, and the brew is covered with a tight-weave fabric or paper coffee filter and left to ferment at room temperature for 7–30 days.
- The living components of SCOBY can vary widely but generally include strains of Saccharomyces cerevisiae and other yeasts, as well as a number of bacteria, including Gluconacetobacter xylinus.
- Fresh or dehydrated SCOBY can be bought from suppliers, or a “mother” can be taken from a previous batch of Kombucha.
- In the fermentation process, the alcohols produced by the yeasts are converted by the bacteria into organic acids.
- The final Kombucha product contains vitamin C, vitamins B6 and B12, thiamine, acetic acid, and lactic acid, as well as small amounts of sugar and ethanol, depending on the length of fermentation.
- The drink can be consumed plain or mixed with fruit juices, or it can be flavoured with spices and herbs; many commercial brews are sweetened and flavoured.
- The SCOBY itself can be eaten fresh or dried and is sometimes used as a meat substitute.