title: Changes in free-radical scavenging ability of kombucha tea during fermentation.
abstract: Kombucha tea is a fermented tea beverage produced by fermenting sugared black tea with tea fungus (kombucha). Free-radical scavenging abilities of kombucha tea prepared from green tea (GTK), black tea (BTK) and tea waste material (TWK) along with pH, phenolic compounds and reducing power were investigated during fermentation period. Phenolic compounds, scavenging activity on DPPH radical, superoxide radical (xanthine-xanthine oxidase system) and inhibitory activity against hydroxyl radical mediated linoleic acid oxidation (ammonium thiocyanate assay) were increased during fermentation period, whereas pH, reducing power, hydroxyl radical scavenging ability (ascorbic acid-iron EDTA) and anti-lipid peroxidation ability (thiobarbituric assay) were decreased. From the present study, it is obvious that there might be some chances of structural modification of components in tea due to enzymes liberated by bacteria and yeast during kombucha fermentation which results in better scavenging performance on nitrogen and superoxide radicals, and poor scavenging performance on hydroxyl radicals.
authors.affiliation: Department of Biotechnology, Sathyabama University, Jeppiar Nagar, Rajiv Gandhi Salai, Chennai 600 119, Tamil Nadu, India.
authors.forename: R
authors.initials: R
authors.lastname: Jayabalan
authors.affiliation: Microbial Biotechnology Division, Department of Biotechnology, Bharathiar University, Coimbatore, Tamil Nadu, India.
authors.forename: P
authors.initials: P
authors.lastname: Subathradevi
authors.affiliation: R&D Centre, Parry Agro Industries Limited, Murugalli Estate, Valparai, Tamil Nadu, India.
authors.forename: S
authors.initials: S
authors.lastname: Marimuthu
authors.affiliation: Department of Food Science and Technology, Institute of Agricultural Science and Technology, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: M
authors.initials: M
authors.lastname: Sathishkumar
authors.affiliation: Microbial Biotechnology Division, Department of Biotechnology, Bharathiar University, Coimbatore, Tamil Nadu, India. Electronic address: kswamibiotech@yahoo.co.in.
authors.forename: K
authors.initials: K
authors.lastname: Swaminathan
keywords: DPPH; Free-radical scavengers; Kombucha; Tea manufacture waste