Probiotics characterization of fermented tiger nut-millet-blended beverage

Abstract This study investigated the functional characteristics and probiotic potential of lactic acid bacteria (LAB) isolated from a fermented tiger nut-millet beverage. The beverage was prepared using a traditional tiger nut fermentation process (sorting, cleaning, soaking, spicing, wet-grinding, fermentation, filtration, chilling, and storage), and samples were collected at 6-hour intervals throughout the 48-hour fermentation time for microbiological analysis. The isolated LAB were evaluated for probiotic properties, including tolerance to acidic pH, bile salts, and phenol. Their antibiotic susceptibility and antibacterial activities against selected pathogenic bacteria were also assessed. LAB counts increased from 2.30 to 6.40 log10 CFU/mL during fermentation. The isolates were identified using the API 50 CHL system and 16S rRNA gene sequencing, revealing members of the genera Leuconostoc and Lactiplantibacillus. Selected isolates exhibited strong tolerance to simulated gastrointestinal conditions, with survival rates exceeding 50% at acidic pH (2.0–3.0), bile salt concentrations (0.3% and 2%), and phenol concentrations (0.2% and 0.3%). The isolates also demonstrated susceptibility to clinically relevant antibiotics and exhibited antibacterial activity against selected foodborne pathogens, producing inhibition zones ranging from 11.0 to 20.0 mm. These findings demonstrate the probiotic potential of LAB and their suitability for developing non-dairy functional foods and nutraceutical products.