PHYSICOCHEMICAL PROFILE AND POTENTIAL NUTRITIONAL BENEFITS OF BIO-TRANSFORMED OKARA

Abstract

In this study, three commercial enzymes (Viscozyme-L, Pectinase-Salus and Cellulase-Salus) were optimized for okara hydrolysis. Viscozyme-L and Pectinase-Salus significantly reduced insoluble dietary fiber (from 65.3% to 46.48% and 45.64%, respectively), released soluble dietary fiber (from 4.47% to 8.76% and 12.13%, respectively) and monosaccharides (xylose, glucose and arabinose). Lacticaseibacillus rhamnosus GG and Lactiplantibacillus plantarum R1012 were grew better in okara treated with Viscozyme-L (8.69 and 9.2-log CFU/mL) or Pectinase-Salus (8.49 and 9.4-log CFU/mL), compared to raw okara (7.69 and 7.79-log CFU/mL). Cellulase-Salus induced limited fiber conversion but released the highest amount of free isoflavone. Combined enzymatic hydrolysis and probiotic fermentation reduced off-flavor compounds (hexanal, 2-hexanal, 2-pentylfuran and nonanal) in okara. Moreover, GPC, FT-IR, proximate analysis and selective fermentation revealed that the soluble fiber in okara hydrolysates were mainly low molecular weight, pectin-like polysaccharides with prebiotic potential. This work demonstrated the potential to combine enzymatic hydrolysis and probiotic fermentation on okara valorization