BIOTRANSFORMATION OF OKARA (SOYBEAN RESIDUE) USING PROBIOTIC BACILLUS SUBTILIS AND BACILLUS COAGULANS

Abstract

Okara (soybean residue), is a side-stream product generated in large amounts from the manufacture of soybean products. This study explored the improvement in nutritional, volatile and physical properties of okara through solid-state fermentation using probiotic Bacillus strains. B. subtilis R0179 converted a significant proportion of okara insoluble dietary fibre to soluble dietary fibre, reduced the levels of hexenal and 2-pentylfuran and released hemicellulosic sugars as well as amino acids in okara. Furthermore, water retention, swelling and emulsification capacities of biotransformed okara increased after 72 h of fermentation. Up to 10 % of this biotransformed okara could be applied as meat extender in pork jerkies with no significant effects on jerky hardness. In contrast, unfermented okara at the same substitution level significantly increased hardness with respect to control jerkies without added okara. These findings suggest the possibility of unlocking greater functional benefits of okara via biotransformation, increasing its potential food applications.