Biological, chemical and antioxidant activities of different types Kombucha
Rania F. Ahmed, Mohamed Hikal, Khadiga Abou-Taleb
Abstract
Three types of Kombucha fermented tea, rice, and barley were produced in order to study their changes of biological and chemical parameters. About a 2-fold increase in mushroom dry weight after 8 days of growth was observed with Kombucha tea. The optical density of the Kombucha extracts gave the same trend. Moreover, Kombucha tea recorded the highest specific growth rate and lowest doubling time. The total acidity, ethanol content, and total protein content were incremented with the fermentation process to reach the peak after 6–8 days as in descending order: tea > barley ≥ rice. The scavenging abilities of DPPH were in descending order, tea (89.69%) > barley (76.19%) > rice (36.04%). The total phenolic compounds of Kombucha tea (88.8 ppm) have the same trend, which more than 3-fold of Kombucha rice (26.11 ppm). Results revealed that the Kombucha tea preservation method using heat treatment (at 76 and 100 °C for 10 min) was not successful, resulting in a decrease in antioxidant amounts to 71.0 and 53.42% and total phenolic compounds to 40.22 and 45.69 ppm, respectively.