Optimization of Probiotic-Fermented Beetroot-Spirulina Protein Health Drink Using Response Surface Methodology: Physicochemical, Microbial, and Sensory Attributes
Abstract
This study developed and optimized a probiotic fermented health drink by incorporating spirulina protein isolate (SPI, 68.2% purity) into beetroot juice using response surface methodology (RSM). Fresh beetroot juice (pH 4.45±0.12, Brix 12.5±0.4) was blended with 2-6% w/w SPI via high-shear mixing, sterilized, and fermented with Lactiplantibacillus plantarum MTCC 1325 and Lacticaseibacillus rhamnosus MTCC 5462 (1:1 consortium, proteolytic activity 2.1±0.2 U/mL). A central composite design (20 runs) optimized temperature (28-42°C), time (24-72 h), inoculum (2-5% v/v), and SPI levels, targeting viable counts (>10^9 CFU/mL), titratable acidity (0.8-1.2%), and sensory acceptability (>7/9). Optimum conditions (35°C, 48 h, 3.5% inoculum, 4% SPI) yielded 1.2×10^9 CFU/mL probiotics (R²=0.958, desirability 0.92), pH 3.98±0.11, acidity 0.92±0.05% lactic acid, and overall acceptability 7.9±0.79. Fermentation enhanced viscosity (42.6±2.1 cP, +31.5%), total phenols (28.4±1.6 mg GAE/100 mL, +43.4%), DPPH IC50 (78±4 μg/mL, -37.1%), and protein digestibility (89.6±2.1%, +14.6%) via synergistic proteolysis and betacyanin hydrolysis. Sensory profiling by 30 panelists confirmed superiority over 6% SPI (5.7±1.19, p6/9, and TPC/YM <10^4 CFU/mL, exceeding FAO/WHO minima. RSM validation (97.8% accuracy) supports scale-up for Indian markets, leveraging Haryana's beet production (2.1 Mt/year) and spirulina's sustainability. This beetroot-SPI synergy delivers a tangy, pink, protein-probiotic beverage masking algal off-notes while boosting functionality.
How to Cite
Taruna, Neeraj Sethi, "Optimization of Probiotic-Fermented Beetroot-Spirulina Protein Health Drink Using Response Surface Methodology: Physicochemical, Microbial, and Sensory Attributes", Vol. 3, Issue 7, 14-10-2025, pp. 23-39.
