Trà kombucha và sức khỏe

The Organic Acids

The kombucha culture is a symbiotic culture of bacteria and yeast, comprising Acetobacter (a genus of acetic acid bacteria) and one or more yeasts. These form a zoogleal mat. In Chinese, this microbial culture is called koubo (Chinese: 酵母; literally "yeast mother").

A kombucha culture may contain one or more of the yeasts Saccharomyces cerevisiae, Brettanomyces bruxellensis, Candida stellata, Schizosaccharomyces pombe, Torulaspora delbrueckii, and Zygosaccharomyces bailii. Alcohol production by the yeast(s) contributes to the production of acetic acid by the bacteria. Alcohol concentration also plays a role in triggering cellulose production by the bacterial symbionts.^{[citation needed]}

Although the bacterial component of a kombucha culture comprises several species, it almost always includes Gluconacetobacter xylinus (formerly Acetobacter xylinum), which ferments the alcohols produced by the yeast(s) into acetic acid. This increases the acidity while limiting the alcoholic content of kombucha. G. xylinum is responsible for most or all of the physical structure of a kombucha mother, and has been shown to produce microbial cellulose.^[1] This is likely due to artificial selection by brewers over time, selecting for firmer and more robust cultures.

The acidity and mild alcoholic element of kombucha resists contamination by most airborne molds or bacterial spores. As a result, kombucha is relatively easy to maintain as a culture outside of sterile conditions. The bacteria and yeasts in kombucha may also produce antimicrobial defense molecules.

The kombucha culture can also be used to make an artificial leather.^[2]