Synergistic Effects of Okara-Based Prebiotic and Lactobacillus plantarum Probiotic: Development of A Nutraceutical Formulation for Gut Health

Probiotics and prebiotics collectively known as synbiotics enhance gut health and microbial activity. The study attempted to develop a freeze-dried synbiotic nutraceutical formulation with Okara as a prebiotic and L. plantarum as a probiotic to improve gut health while preserving beneficial microbes. L. plantarum was morphologically characterized using biochemical assays, and enzymatic profiling was performed with VITEK 2C. Okara's protein content and ash levels were examined to evaluate its pharmacognostic characteristics and prebiotic efficacy was assessed at 1%, 2%, 3%, and 4% concentrations, emphasizing specific growth rate, pH, % titratable acidity, and dry biomass. Nine batches of a synbiotic powder formulation containing cryoprotectants such as mannitol, sorbitol, and maltodextrin, with probiotics and prebiotics, were freeze-dried. Three of the nine batches have been selected, with B2 selected for further examination. L. plantarum viability was evaluated before and after freeze-drying and storage at 4-8 °C. The prebiotic efficacy test demonstrated that 2% okara resulted in significant growth, indicating significant L. plantarum proliferation. After 48 hours, the pH declined to 4.24, and the percentage titratable acidity gradually increased, indicating significant lactic acid production. The dry biomass content was maximum at 2% okara. Following freeze-drying, viable counts decreased to 3.78 ± 0.045 log CFU/mL and 3.54 ± 0.015 log CFU/mL after 7 days of storage. Batch B2 demonstrated excellent flow properties, smaller particle size with minimum drying loss. At 48 hours, the zone of inhibition against E. coli was demonstrated to be highly susceptible. L. plantarum counts increased to 9.68 ± 0.19 log CFU/mL after 48 hours in the in vitro co-culture investigations with E. coli. However, the number of E. coli bacteria decreased significantly. The combination demonstrated remarkable effectiveness in enhancing L. plantarum proliferation while suppressing E. coli, indicating plausible uses in nutritional supplements for promoting gut health.