Fermentation kinetics in kombucha tea with tea kind variation based on its processing

Ardheniati M, Andriani MAM, Amanto BS. 2009. Fermentation kinetics in kombucha tea with tea kind variation based on its processing. Biofarmasi 7: 48-55. Tea (Camellia sinensis) is one of agriculture commodities which contains powerful substance, especially in health sector. The kinds of tea in Indonesia are green tea and black tea. Kombucha tea is made from water and tea boiled with fermentation process about 8-12 days. It consists of complex material changed by Acetobacter xylinum bacteria and Saccharomyces cerevisiae leavened. The purpose of the research was to find out the impact of the kinds of tea toward kombucha tea fermentation kinetics with the parameter of specific growth pace (µ), cell growth result (Yx/s), product formation (Yp/s), generation time (td), and the amount of multiplication (N). This research was done in UPT Central Laboratory of MIPA Faculty, Sebelas Maret University, Surakarta. The fermentation process optimization was done with the amount of inoculum of 10% (v/v), the temperature of 30oC and the initial sugar content of 10% (b/v). The analysis toward sugar content reduction, acetate acid content, pH value, and kombucha tea microbiology was done about 8 days of fermentation with 24 hours interval. The data generated were treated by a descriptive analysis and t-test investigation, so that the difference of fermentation kinetics between green kombucha tea and black kombucha tea could be found. The results of the research showed that the fermentation kinetic of green kombucha tea had an aerobe and anaerobe specific growth pace of 0.055/hour and 0.015/hour, respectively, cell growth result 1.901x107 cfu/mg, product formation 0.064, the efficiency of acetic acid production toward sugar reduction 11.814%, the generation time in aerobe and anaerobe condition 12.6 and 46.2 hours, respectively, and the amount of multiple of 3.583 times. Meanwhile, the fermentation kinetic of black kombucha tea showed an aerobe and anaerobe specific growth pace of 0.054/hour and 0.018/hours, respectively, cell growth result 2.425x107 cfu/mg, product formation 0.081, the efficiency of acetic acid production toward sugar reduction 11.510%, the generation time in aerobe and anaerobe condition 12.8 hours and 38.5 hours, respectively, and the amount of multiple 3.583 times. From t-test investigation, it was found that the aerobe specific growth pace, the efficiency of acetic acid production toward sugar reduction, the aerobe generation time, the cell growth, and the product formation were not significantly different. Meanwhile, the anaerobe specific growth pace, the anaerobe generation time, and the amount of multiple were significantly different.