Evaluation of physicochemical and bioaccessibility properties of goji berry kombucha

Abstract

Kombucha is an ancestral beverage that is made by fermentation of sweetened tea, involving symbiosis of acetic acid bacteria and yeast species. In this study, red goji berry (Lycium barbarum L.) and black goji berry (Lycium ruthenicum Murr.) were selected as substrates for kombucha beverage production and their physicochemical, sensory and in vitro total phenolic and antioxidant bioaccesibility properties were compared to black tea kombucha. Total phenolic content of all kombucha samples fluctuated during fermentation and storage. All kombucha samples had higher antioxidant activity than their infusions. Total phenolic content and antioxidant capacity in in vitro predigestion and postdigestion of samples observed as follows: black tea kombucha > black goji berry kombucha > red goji berry kombucha. Present study demonstrated that black goji berry and red goji berry fruits were suitable for kombucha beverage production. However, black goji berry kombucha was the most desirable beverage in all terms of sensory properties. PRACTICAL APPLICATIONS: Kombucha is an ancestral beverage that made by fermentation of sweetened tea, involving symbiosis of acetic acid bacteria and yeast species. It is accepted as functional beverage having antihypertrophic, antihyperglycemic, antihyperlipidemic, and membrane stabilizing properties. Consumption of goji products has increased due to their claimed health benefits including the treatment of diseases related to liver, kidney, eyesight, immune system, and circulation. In this study, black and red goji berries were used for kombucha production in order to design a beverage with desirable sensory characteristic, high antioxidant activity as well as high bioaccessibility.