Effects of Different Inocula Fermentation on Physicochemical, Nutritional and Antioxidant Activities of Non-Alcoholic Finger Millet (<i>Eleusine coracana</i> L.) Beverages

The rising demand for plant-based, lactose-free functional beverages amid gut health concerns positions finger millet (FM, <i>Eleusine coracana</i>) as a promising substrate. This study assessed sprouting and fermentation inoculum effect: dairy starters (<i>Streptococcus thermophilus</i> and <i>Lactobacillus bulgaricus</i>) or backslopping with commercial <i>Mageu</i> on microbial growth, fermentation dynamics, nutrition, antioxidants, color, and texture of FM beverages. Microbial growth increased modestly over 48 h OD₆₀₀ = 0.169–0.201, peaking in non-sprouted FM with dairy starters (ND) at OD600 = 0.201). ND showed the fastest pH decline (ΔpH = 2.19), while sprouted FM with dairy starters (SD) or backslopping (SB) had controlled acidification. Total titratable acidity increased from 0.14 to 0.66%, with the highest total soluble solids in sprouted substrates (SD = 11.26 °Brix; SB = 10.97 °Brix). Proximate analysis revealed SB had high crude fiber (2.86%) and SD highest protein (4.02%). Sprouted beverages excelled in minerals (SB Ca = 27.00 mg/100 g; SD Ca = 25.75 mg/100 g), while ND or non-sprouted FM fermented spontaneously (NS) had high Fe (4.31%, 2.65%) and K (48.08%, 38.32%). ND showed peak antioxidants: phenolics 10.54 µg/mL, DPPH 87.80%, FRAP 21.24 µM Fe²⁺/g, ABTS 79.09%. Sprouted beverages displayed distinct color (<i>L</i>* = 37.67–39.65, <i>C</i>* = 25.94–27.03) versus commercial <i>Mageu</i> (<i>L</i>* = 57.89, <i>C</i>* = 14.50) and favorable texture (firmness 12.78–13.40 g, secondary peak force ~−7.2 g). Controlled fermentation of sprouted FM yields nutrient-dense, antioxidant-rich, vegetarian beverages with superior attributes, affirming its functional potential.