Presenter: Syeda Faatima Zahraa Adnan

Faculty Sponsor: Kathleen C. Murphy

School: Worcester State University

Research Area: Chemistry and Materials Science

Session: Poster Session 2, 11:30 AM - 12:15 PM, 165, D15

ABSTRACT

This study investigates fermentation kinetics in black tea and green tea kombucha by quantifying changes in ethanol and acetic acid concentrations over a 21-day fermentation period. Kombucha is produced using a symbiotic culture of bacteria and yeast (SCOBY), in which yeast convert sugars into ethanol through anaerobic fermentation and acetic acid bacteria subsequently oxidize ethanol into acetic acid under aerobic conditions. The primary objective of this project is to evaluate whether ethanol depletion directly corresponds to acetic acid accumulation during fermentation and to determine whether tea type influences metabolic progression due to differences in substrate composition.

Kombucha samples are collected at 7-day intervals and stored at 20 °C to prevent further fermentation prior to analysis. Acetic acid concentrations are quantified using high-performance liquid chromatography (HPLC) with standard addition to improve analytical accuracy and compensate for matrix effects. Ethanol concentrations are measured using headspace gas chromatography (GC), which analyzes volatile organic compounds in the vapor phase above sealed liquid samples. An internal standard is incorporated into the GC method to improve precision and account for variability in sample preparation and injection.

By comparing metabolic trends between green and black tea substrates, this project aims to characterize the biochemical relationship between ethanol oxidation and acetic acid production within the SCOBY consortium and to assess how substrate composition influences microbial activity and fermentation dynamics.