Formulation of synbiotic soy-based food product with antihypertensive potential

The specific aims of this study were to select the favorable prebiotic for L casei-01 as well as the suitable inoculum of the probiotic for fermented soy with ACE-inhibitory potential. For that purpose the metabolic activity of L casei-01 in soymilk supplemented with(1.5% w/v) prebiotics Fructooligosaccharide (FOS) or oligofructose enriched inulin (Synergy 1) was assessed. The evaluated parameters were: pH, viable cell counts, proteolysis, organic acid production and inhibition of angiotensine converting enzyme activity (IACE). The cell growth of L casei-01 reached the recommended therapeutic level of 9.58 ± 0.035 log cfu mL-1 for low inoculum samples (0.005 and 0.01%w/v) and 11.543 ± 0.13 log cfu mL-1 for high inoculum samples (0.075 and 0.1%w/v) regardless of the prebiotic used. The lower pH during fermentation, faster cell growth and superior proteolysis in Synergy 1 samples indicated better utilization of that prebiotic vs. FOS. The hydrolysis depended on the prebiotic used, showing higher values in Synergy 1 samples. The faster proteolysis was confirmed by SDSPAG electrophoresis. The Mw of polypeptides in the synbiotic end-products were lower than 30kD. The observed values for inhibition of ACE activity were app. 71, 74, 77 and 78% for inoculum rates of 0.005, 0.01, 0.075 and 0.1% w/v, respectively. Based on the results obtained in our study, the prebiotic Synergy 1 (1.5% w/v) and L. casei-01 at inoculum of 0.01% w/v for low dose and 0.075% w/v for high dose were considered more favorable for the production of synbiotic soy drink with antihypertensive potential.