The antioxidant activity of kombucha fermented milk products with stinging nettle and winter savory
JASMINA S VITAS, RADOMIR V MALBASA, JOVANA A GRAHOVAC, EVA S LONCAR
This paper investigates the antioxidant activity of fermented milk products obtained by kombucha fermentation. Two starter cultures were used as follows: starter obtained after kombucha fermentation on sweetened stinging nettle extract, and starter obtained after kombucha fermentation on sweetened winter savory extract. The starters were added to milk with 0.8, 1.6 and 2.8% milk fat. Fermentation was carried out at 37, 40, and 43C and stopped when the pH reached 4.5. Antioxidant activity to hydroxyl and DPPH radicals was monitored using response surface methodology. Kombucha fermented milk products with stinging nettle (KSN) and with winter savory (KWS) showed the same antioxidant response to hydroxyl and different responses to DPPH radicals. The synergetic effect of milk fat and fermentation temperature to antioxidant activity to hydroxyl radicals for both types of kombucha fermented milk products (KSN and KWS) was established. The optimum processing conditions in terms of antioxidant activity were: milk fat around 2.8% and process temperature around 41 and 43C for KSN and KWS, respectively.
Keywords: kombucha, fermented milk products, antioxidant activity, stinging nettle, winter savory.
Citation: Chemical Industry & Chemical Engineering Quarterly 19 (1) 129?139 (2013)
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Date Updated: February 10, 2020