Efficacy of Fermented Teas in Antibacterial Activity

Authors:
Sulak Talawat, Pimpan Ahantharik, Sajeena Laohawiwattanakul, Apinya Premsuk, Sunanta Ratanapo

Abstract:
Fermented tea or "Kombucha" was prepared by a tea broth (1.7 % w/v) and sucrose (10% w/v)
with supplement of commercially available starter culture. Teas used in this study were mulberry tea,
Japanese green tea, Jasmine tea, Ulong tea, and black tea. The teas were fermented for two weeks as an inoculum, following by inoculation to another tea broth and required further two-week static fermentation. In this study, the antibacterial activity of several teas were tested against pathogenic bacteria in human and shrimp (e.g., Vibrio cholerae, Salmonella typhi, Pseudomonas aeruginosa, Vibrio harveyi, Vibrio parahaemolyticus, Vibrio alginolyticus, and Vibrio vulnificus) by disc agar diffusion assay. The pH of fermented teas decreased from around 5 to 2, and the OD600 of tea broth rose significantly from around 0 to 1.5 during the fermentation period. Broth from black tea poses the greatest inhibitory activity by measuring diameters of inhibition zones. V. parahaemolyticus showed the largest susceptibility to fermented tea, while pathogenic bacteria in humans appeared to be less sensitive. Changes in major components of tea broth were also observed by HPLC analysis. The key organic acids, such as succinic acid and gluconic acid produced during the period, increased with time, proving the major role of these acids in the microorganism's growth inhibition.


Keywords: fermented tea, kombucha, tea fungus, pathogenic bacteria, acetobacters



Country: Thailand

Citation: Kasetsart J. (Nat. Sci.) 40 : 925 - 933 (2006)

Study Mailing Address:
Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.

Date Updated: January 14, 2021