A new functional kefir fermented beverage obtained from fruit and vegetable juice: Development and characterization

A juice containing a mixture of fruits and vegetables (70% apple, 9% strawberry, 12% carrot and beet 9%) was evaluated as a potential substrate for the production of a novel probiotic beverage made with kefir grains. The effects of the kefir grains amount (1–4%, w/v) and fermentation time (12, 24 and 48 h) on the beverage composition, sensory qualities and colour were investigated. The results indicated that the amount of kefir grains have a significant effect on the content of the organic acids (lactic, acetic, citric, succinic, and malic acid), CO2 production, acidity, and viscosity and colour parameters (lightness (L*), hue (hab) and Chroma (C*ab)). Fermentation time also significantly affected all the parameters analyzed in the samples. The most suitable conditions to achieve the highest overall acceptability for the fermented beverage based on a mix of fruits and vegetable juice was: 2% (w/v) kefir inoculum during 24 h of fermentation time. •Juice fermented with kefir was evaluated to produce a novel probiotic beverage.•The effects of kefir amount and fermentation time on the beverage were investigated.•Fermented juice promoted changes in physico chemical, sensory and colour parameters.•Changes in physico chemical properties of beverages have a beneficial health effect.