Effect of Brown Algae and Lichen Extracts on the SCOBY Microbiome and Kombucha Properties

Kombucha tea was made by the fermentation of SCOBY culture of green tea broth with the addition of Fucus vesiculosus algae extract, Cetraria islandica lichen extract and their mixture. Kombucha was also made without the herbal supplements as a control. After 11 days of fermentation, in addition to the yeast Brettanomyces bruxellensis and the bacteria Komagataeibacter rhaeticus and Komagataeibacter hansenii contained in all of the samples, the yeast Zygosaccharomyces bailii and bacteria Komagataeibacter cocois were detected in the samples with the herbal extracts. In all of the kombucha with herbal additives, the total fraction of yeast was decreased as compared to the control. The total content of polyphenols and the antioxidant activity of the beverages with and without the addition of herbal extracts were comparable. The kombucha made with the algae extract showed an increased content of sucrose and organic acids, while the fructose and glucose content in the samples with algae and the mixture of extracts were lower than in the other samples. The samples with the algae extract had the highest organoleptic indicators aroma, clarity and acidity, while the control samples had slightly higher indicators of taste and aftertaste. The results of this study indicate the potential of algae and lichens as functional supplements for obtaining non-alcoholic fermented beverages with additional nutraceutical value.

Automated summary

Kombucha tea was fermented with the SCOBY culture of green tea broth and the addition of Fucus vesiculosus algae extract, Cetraria islandica lichen extract and their mixture. The presence of yeast Zygosaccharomyces bailii and bacteria Komagataeibacter cocois was detected in the samples with herbal extracts. The kombucha with herbal additives showed a decrease in yeast fraction compared to the control, but the polyphenols content and antioxidant activity were comparable. The algae extract enhanced the sucrose and organic acids content in the kombucha, while the fructose and glucose content were lower in samples with algae and the mixture of extracts. The samples with algae extract had the highest organoleptic indicators, while the control samples had slightly higher taste and aftertaste indicators. These findings suggest the potential of algae and lichens as functional supplements for non-alcoholic fermented beverages.