Kombucha based on unconventional parts of the Hibiscus sabdariffa L.: Microbiological, physico-chemical, antioxidant activity, cytotoxicity and sensorial characteristics

This study aimed to develop and characterize two new types of kombucha beverages on H. sabdariffa L. of leaves and stems. For kombucha production, the microorganism's growth conditions in the tea from the leaves or stems were first evaluated. After that, the flavoring of the beverages with grape juice was performed. For the kombucha beverage on H. sabdariffa leaves, the optimized fermentation conditions were 5.93% leaves and 5.81% sucrose; for the kombucha beverage on H. sabdariffa stems, they were 4.75% stems and 9.30% sucrose. The fermentation and flavoring increased the phenolic and flavonoid compounds and the antioxidant activity. For the cytotoxicity, the incubated cells' morphologies and cell viability were not affected by the kombuchas. The two new types of grape-flavored kombucha beverages on H. sabdariffa were characterized by the sensory panel as vinegar aroma, leaves H. sabdariffa flavor, vinegar flavor, sour taste, and concentrated. The two new types of grape-flavored kombucha beverages on H. sabdariffa were well accepted. The results showed that the leaves and stems of the H. sabdariffa are potential raw materials for kombucha production.