Starter Culture Optimization for Cereal- and Millet-Based Fermented Beverages

Natural and standardized mixed starter systems were successfully evaluated for fermentation of six cereal and millet matrices. The natural starter containing 5% curd and 2% sugar showed substrate-dependent fermentation, requiring 12 h for white rice, red rice, and barley and 24 h for finger millet, pearl millet, and sorghum. Growth-kinetic analysis further demonstrated differences among the grain matrices. In comparison, the 5% mixed starter achieved a presumptive LAB population of 2.19 × 1010 CFU/mL within 6 h, with pH 4.35 ± 0.078, titratable acidity of approximately 0.841% lactic acid, μmax of 2.88 h−1, and a calculated doubling time of 0.24 h. These findings demonstrate the importance of substrate-specific fermentation conditions and show that controlled mixed inoculation can shorten fermentation under the tested conditions. Further independent-batch validation, molecular confirmation of starter organisms, strain-specific enumeration, substrate-consumption analysis, sensory evaluation, and storage-stability studies are required before strain-specific probiotic or commercial shelf-life claims can be established

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