Changes in the content of total polyphenols and the antioxidant activity of different beverages obtained by Kombucha ‘tea fungus’

Hazal Özyurt

doi:10.31015/jaefs.2020.3.3

Abstract

Kombucha ‘tea fungus’ is a traditional refreshing drink obtained by fermentation of black tea with sugar as well as a strong symbiosis of acetic bacteria and yeasts. Kombucha tea has several health benefits such as antihyperglycemic, antilipidemic, antimicrobial, hepatoprotective, hypocholesterolemic and anticancer effects due to their antioxidant activity. In this study, six kombucha beverages were prepared by placing Kombucha ‘tea fungus’ in green, black and Echinacea teas, as well as goat, cow and soy’s milk. The fermentation process was monitored by pH, total sugar amount, and titratable activity, as well as their antioxidant activities and total phenolic contents, were analyzed prior to the fermentation process and at the end of fermentation. The results showed that tea-based beverages were fermented for nine days and milk-based beverages were for 6 hours. Their sugar contents were significantly decreased (p &lt; 0.05) as depending on their sugar contents. All fermented beverages displayed a statistically significant decrease (p &lt; 0.05) in the DPPH and ABTS radical scavenging activity at the end of fermentation, while FRAP assays were displayed a statistically significant increase (p &lt; 0.05). Further studies are necessary to the research of nutrients of tea and milk-based beverages on human organs the throughout fermentation.

Highlights

Since consumers have become increasingly aware of the role of diet in promoting health and preventing disease, new food products called functional food have been improved
The overall decrease in pH of the beverages would have been due to the increased concentration of organic acids produced during the fermentation process by Kombucha ‘tea fungus’ as inoculum (Battikh et al, 2012)
The present study demonstrated that milk and tea-based beverages prepared from different substrates have excellent antioxidant activities

Summary

Introduction

Since consumers have become increasingly aware of the role of diet in promoting health and preventing disease, new food products called functional food have been improved. Functional foods have a positive effect on health, physical and mental condition of the human body in addition to the nutritional value and the most famous examples of functional foods are fermented products, especially milk or dairy products (Siró, Kápolna, Kápolna, and Lugasi, 2008). Kombucha is a symbiosis of acetic acid bacteria (Acetobacter), including Acetobacter xylinum, A. xylinoides, Bacterium gluconicum, A. suboxydans, Gluconobacter liquefaciens, A. aceti and A. pasteurianus, various yeasts (the genera of Brettanomyces, Zygosaccharomyces, Saccharomyces, and Pichia depending on the source), including Saccharomyces cerevisiae, S. inconspicus, S. ludwigii, Schizosaccharomyces pombe, Candida tropicalis, C. krusei, Debaryomyces hansenii, Brettanomyces spp., Kloeckera spp., Zygosaccharomyces bailii and Z. Kombucha is composed of a floating cellulosic pellicle layer and the sour liquid broth (De Filippis, Troise, Vitaglione, and Ercolini, 2018) and converted the sugar which is its carbon source into organic acids and ethanol: sucrose into glucose and fructose and produce ethanol, while acetic acid bacteria convert glucose into gluconic acid and fructose to acetic acid

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