Fermentation of sugared tea with a symbiotic culture of acetic acid bacteria and yeast (tea fungus) yields kombucha tea which is consumed worldwide for its refreshing and beneficial properties on human health. Important progress has been made in the past decade concerning research findings on kombucha tea and reports claiming that drinking kombucha can prevent various types of cancer and cardiovascular diseases, promote liver functions, and stimulate the immune system. Considering the widespread reports on kombucha, we recognized the need to review and update the research conducted in relation to kombucha tea, its products and tea fungus. Existing reports have suggested that the protective effects of kombucha tea are as good as those of black tea, however, more studies on kombucha tea and its composition are needed before final conclusions can be made.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/1541-4337.12073

A review on kombucha tea - microbiology, composition, fermentation, beneficial effects, toxicity, and tea fungus.

This study evaluated the effect of fermentation on the nutritional quality of food-grade soybeans and feedgrade soybean meals. Soybeans and soybean meals were fermented by Aspergillus oryzae GB-107 in a bed-packed solid fermentor for 48 hours. After fermentation, their nutrient contents as well as trypsin inhibitor were measured and compared with those of raw soybeans and soybean meals. Proteins were extracted from fermented and non-fermented soybeans and soybean meals, and the peptide characteristics were evaluated after electrophoresis. Fermented soybeans and fermented soybean meals contained 10% more (P 60 kDa) (P < .05). Fe...

Aspergillus oryzae GB -107 fermentation improves nutritional quality of food soybeans and feed soybean meals

Glucosinolates in crop plants

Changes in content of organic acids and tea polyphenols during kombucha tea fermentation

Yeast ecology of Kombucha fermentation.

Kombucha was prepared in a tea broth (0.5% w/v) supplemented with sucrose (10% w/v) by using a commercially available starter culture. The pH decreased steadily from 5 to 2.5 during the fermentation while the weight of the 'tea fungus' and the OD of the tea broth increased through 4 days of the fermentation and remained fairly constant thereafter. The counts of acetic acid-producing bacteria and yeasts in the broth increased up to 4 days of fermentation and decreased afterward. The antimicrobial activity of Kombucha was investigated against a number of pathogenic microorganisms. Staphylococcus aureus, Shigella sonnei, Escherichia coli, Aeromonas hydrophila, Yersinia enterolitica, Pseudomonas aeruginosa, Enterobacter cloacae, Staphylococcus epidermis, Campylobacter jejuni, Salmonella enteritidis, Salmonella typhimurium, Bacillus cereus, Helicobacter pylori, and Listeria monocytogenes were found to be sensitive to Kombucha. According to the literature on Kombucha, acetic acid is considered to be responsible for the inhibitory effect toward a number of microbes tested, and this is also valid in the present study. However, in this study, Kombucha proved to exert antimicrobial activities against E. coli, Sh. sonnei, Sal. typhimurium, Sal. enteritidis, and Cm. jejuni, even at neutral pH and after thermal denaturation. This finding suggests the presence of antimicrobial compounds other than acetic acid and large proteins in Kombucha. Chemicals/CAS: Plant Extracts; Sucrose, 57-50-1

Kombucha fermentation and its antimicrobial activity

A description is given of the solid-state fermentation of wheat bran by Trichoderma reesei QM9414 at constant temperature and relative humidity. Glucosamine, the oxygen consumption rate (OCR), the carbon dioxide production rate (CPR), changes in wheat bran composition and the production of four enzymes were measured during 125 h of fermentation. A C balance was set up between CO2 production, based on CPR measurements, CO2 production as expected on the basis of substrate composition changes and substrate elemental composition in combination with dry-matter weight loss. Glucosamine was used as the measure of biomass. The results indicate that the glucosamine content of fungi in liquid culture cannot be used to estimate the biomass content in solid-state fermentations. Using glucosamine, correlations between fungal growth and respiration kinetics could only partly be described with the linear-growth model of Pirt. A decline in OCR and CPR started the moment the glucosamine level was 50% of its maximum value. After the glucosamine level had reached its maximum OCR and CPR continued to decline. The activities of xylanase and protease are linearly related to the glucosamine level. No clear correlations between glucosamine and carboxylmethylcellulose-hydrolysing enzyme activity and amylase activity were found.

Solid-state fermentation of wheat bran by Trichoderma reesei QM9414: substrate composition changes, C balance, enzyme production, growth and kinetics.

A novel solid-state fermentation method using polyurethane foam as inert carrier impregnated with a synthetic liquid medium was developed simulating the nutritional composition and culture conditions of solid-state fermentation on wheat bran. With this system, biomass, the important parameter involved in solid-state fermentation processes, can be measured directly. Some other superiorities of this system over conventional solid-state fermentation systems are discussed.

A novel solid-state fermentation system using polyurethane foam as inert carrier

Fermented tea drink, Kombucha, can inhibit the growth of Shigella sonnei, Escherichia coli, Salmonella enteritidis and Salmonella typhimurium. Several metabolites were analyzed every two days during a 14-day Kombucha fermentation. Levels of acetic acid and gluconic acid were found to increase with fermentation time. No lactic acid or ethanol was detected. Systematic investigation of the antimicrobial activity in Kombucha revealed the presence of antimicrobial compounds other than organic acids or proteins (enzymes) produced during fermentation or the tannins originally present in the tea broth.

W. Knol

Papers

Kombucha fermentation and its antimicrobial activity

Solid-state fermentation of wheat bran by Trichoderma reesei QM9414: substrate composition changes, C balance, enzyme production, growth and kinetics.

A novel solid-state fermentation system using polyurethane foam as inert carrier

Characterization of Antimicrobial Activity in Kombucha Fermentation

Accurate determination of process variables in a solid-state fermentation system