Kombucha is a fermented beverage that is produced by fermenting tea and beet sugar solution under aerobic conditions by adding symbiotic culture (yeasts and acetic acid bacteria) named as SCOBY. The health benefits of Kombucha are mainly associated with the phenolic content of substrate and the microbiota of Kombucha cultures. Olive leave and honey contain various antioxidant phytochemicals and have been used as folk medicine for long time in the form of infusion or can also be used directly. Phenolic compounds play role as antioxidant to reduce cardiovascular and neurodegenerative diseases. They also cause to weight loss, reduce the dimension of adipose tissue and blood triglyceride level, promote digestion, and lower the inflammation.
The main objective of this research was to develop a beverage using dried olive leaf (0-5%) and honey (20 °Brix) as an alternative to beet sugar required for the Kombucha fermentation. Phenolic contents of extractable and hydrolysable extracts and the antioxidant activity of the fermented Kombucha beverages supplemented with beet sugar were higher following to the fermentation. The maximum phenolic contents were determined at the 12th day. However, the bioavailability of phenols in the beverages supplemented with honey and olive leaves was much higher than the samples supplemented with beet sugar only.