Antioxidant Potential and Composition of Winery Effluent Based Kombucha Products.

Purpose: This study further examined the biological potential of winery effluent based kombucha products. The antioxidant compounds and antioxidant potential of obtained kombucha samples were determined. Methods: In order to establish the most suitable fermentation parameters the kombucha fermentation process was performed at 20, 25 and 30 °C on the winery effluent substrate with 3, 5 and 7% of total sugars during 0, 3, 6 and 9 days. The antioxidant potential was measured by DPPH and hydroxyl radical scavenging capacity, as well as reducing power determination by spectrophotometric methods. Very well-known antioxidant compounds, vitamin C and phenolic acids were determined by HPLC and total phenols were determined by spectrophotometric method. Results: The content of vitamin C, total phenols and phenolic acids (gallic, p-hydroxybenzoic, caffeic, syringic, p-coumaric acid) was measured. All samples showed the DPPH and hydroxyl radical scavenging capacity, as well as reducing power. Conclusion: The most suitable production variables for kombucha beverage with the highest antioxidant potential were 25 °C and 3 days of fermentation. Statistical analysis indicated strong positive correlation between gallic acid content and DPPH radical scavenging capacity and gallic acid content and reducing power. Modelling of antioxidant potential and antioxidant compounds content was performed. [ABSTRACT FROM AUTHOR]