High hydrostatic pressure aided by food-grade enzymes as a novel approach for Okara valorization

Abstract Okara is a cheap, abundant and valuable by-product from soybean but it needs an easy industrial method to maximize its soluble dietary fibre (SDF) content. A novel combination of high hydrostatic pressure (HHP) assisted by the food-grade enzyme Viscozyme ® L was simultaneously used for this purpose. Viscozyme ® L (0.025%) was able to degrade Okara at atmospheric pressure in 120–180 min, and the most effective conditions were found at pH 7 and 37 °C (9.3% SDF). Synergy between HHP and Viscozyme ® L was observed, in terms of SDF release and molecular weight decrease, as determined by direct High Performance Liquid Chromatography - Evaporative Light Scattering Detector analysis (HPLC-ELSD). In fact, at 600 MPa, 0.025% Viscozyme ® L and 30 min treatment, SDF and polysaccharides content were 2.50 and 3.20-times higher than in native Okara, achieving a concentration of 13.53 ± 0.30% (SDF), which improved its nutritional value and applicability in functional foods. Industrial relevance HHP is a novel technological process which is useful for increasing the added value of by-products like Okara by solubilizing their dietary fibre. Some enzymes increase their activity when they are under HHP. A simultaneous method with Viscozyme ® L and HHP on Okara has been optimized for reducing the industrial cost of the process.