The evaluation of black carrot, green cabbage, grape, and apple juices as substrates for the production of functional water kefir-like beverages.

Water kefir (WK) is a nondairy probiotic beverage produced using water kefir grains that are highly adaptable to diverse food substrates. Fruit and vegetables have been used more in beverage production in recent years due to their plentiful nutritional qualities. In this context, the aim of this study is to develop fruit-vegetable juice-based beverages fermented with WK grains in order to produce novel, non-dairy, probiotic water kefir-like beverages (W-KLBs) with improved sensory and nutritional properties. In this context, black carrot (BC), apple (A), grape (G), and green cabbage (GC) juices are fermented with commercial WK grains. Results showed that BC-KLB possessed the highest antioxidant activity (75.50%), total phenolic (1248.60 mg GA/L), and total monomeric anthocyanin (391.31 mg/L as cyaniding-3-glucoside equivalent) content. Also, the sensory evaluation demonstrated that BC-KLB was the most favorable sample, while GC-KLB received negative feedback. These findings strongly support the suitability of BC juice to develop W-KLB with high added value and functional properties.