Journal of Food Processing & Technology

Abstract

Evaluation of Chemical and Microbiological Characteristics of Kombucha Tea Produced during an Extended Fermentation

Dillon Lorraine* and Hamid B. Ghoddusi

Kombucha tea is a non-alcoholic beverage, acquiring significant interest due to claimed medicinal properties. In this study, the chemical and microbial properties of kombucha cultivated on Green (GT) Black (BT) and a combination of 1:1 Green and Black Tea (GBT) at different time points up to 26 days of fermentation were evaluated. Emphasis was placed on determining health promoting organic acid contents, namely Glucuronic Acid (GlcUA), Acetic Acid (AA) and Lactic Acid (LA) and purine alkaloid caffeine in three Kombucha formulations by High- Performance Liquid Chromatography (HPLC). Furthermore, Kombucha samples were enumerated on MRS agar for Lactic Acid Bacteria (LAB). The effect of an extended fermentation was monitored for changes to sucrose content and pH values.

Organic acids were determined using the liquid chromatograph coupled to a photo-diode detector, using reversed phase (C18 column) and isocratic elution with 3% phosphoric acid 97% and methanol 3% as mobile phase. Determination of caffeine was also carried out by HPLC equipped with a UV detector under isocratic conditions with 0.5% Trifluoracetic (TFA) 83% and methanol 17% (83:17). The method validation parameters showed efficiency, coefficient of variation between 0.47% and 3.07% (n=3) for repeatability. The average concentrations of caffeine, GlcUA, AA and LA were found in the ranges of 0.24-0.30 mg/ml, 1.74-2.35 mg/ml, 6.01-8.99 mg/ml, 0.47-0.55 mg/ ml, respectively. GT as a substrate produced significantly higher amounts of GlcUA in Kombucha compared to BT and GBT (P ≤ 0.05). GT produced higher amounts of caffeine compared to BT and GBT. Maximum LAB numbers were achieved on day 13 in all samples, with GBT being the highest.

Published Date: 2024-07-29; Received Date: 2020-05-25