Background: Vinegar could be counted as one of the oldest acetic acid diluted solution
products among the history. It can be produced by various fermentation methods using any sugary
substrate, especially fermented fruit juice. Due to the presence of many kinds of compounds which
formed in the fermentation process, the final vinegar products could show unique functions. The aim
of current study was to produce a new type of vinegar kombucha using different fruit juices substrates.
Methods: Kombucha vinegar was obtained by fermentation of kombucha broth layer on sweetened
pasteurized fruit juices (pomegranate, red grape, sour cherry and apple). Fermentation took
place in 4 L glass vessel and fortified with 2% of previously processed broth. Incubation was
carried out at 27±2 °C for 14 days. Several factors such as; pH, total acidity, and acetic acid content,
invert sugars, remaining sucrose, alcohol, soluble solids and the yield of biomass were
measured periodically (0, 3, 7, 10 and 14 days after processing).
Results: As the fermentation continues, the actual concentration of acids, pH value, fructose content
and biomass yield significantly increased (P<0.01) but the alcohol and residual sucrose content
decreased in all the juices.
Contents of acetic acid on 14th day of fermentation were 3.8, 3.6, 3.5 and 3.4 g/100 ml of pomegranate,
red grape, sour cherry and apple juice vinegar, respectively. Moreover, soluble solid in
kombucha vinegar was determined (24.7, 38.1, 19.1 and 36.5 g/100 ml in pomegranate, red
grape, sour cherry, and apple, respectively).
Conclusion: The composition of different kombucha preparations is greatly affected by the individual
kombucha layer used.