Optimization of Water Kefir-based Fermentation Formula of Beetroot (<i>Beta vulgaris</i> L.), Cinnamon (<i>Cinnamomum verum</i>), and Red Ginger (<i>Zingiber officinale Roscoe</i>) for Enhanced Betalain

Recent trends in functional beverage development have highlighted the potential of fermented plant-based products with enhanced bioactive properties. This study explores the incorporation of beetroot (Beta vulgaris L.) in water kefir production and optimizes its formulation through the addition of red ginger and cinnamon to enhance antioxidant and sensory properties. The primary bioactive compound, betalain, present in beetroot contributes substantially to its antioxidant capacity. Recent research, the formulation optimization was conducted through Mixture Design D-Optimal by Design Expert, which systematically evaluated varying concentrations of beetroot (55-70%), red ginger (20-35%), and cinnamon (10-25%) to determine their optimal proportions. The optimized formulation was fermented with water kefir grains for 48 hours at 28°C, resulting in enhanced antioxidant activity through multiple pathways, such as microbial enzymatic degradation of complex compounds, generation of secondary metabolites, and improved bioavailability via cell matrix breakdown. The optimal formulation, comprising 59.528% beetroot, 30.472% cinnamon, and 10.000% red ginger, demonstrated remarkable results with a betalain content is 53.448 mg/100 g achieving a desirability value of 0.785. This research successfully establishes a novel, plant-based functional beverage with elevated antioxidant capacity, offering a viable alternative for health-conscious consumers and those with dairy sensitivities while advancing the field of functional fermented beverages.