Okara is an abundant, inexpensive and rich in dietary fibre by-product from soybean with potential prebiotic effect, although an increase in soluble dietary fibre (SDF) and low molecular weight carbohydrates (LMWC) would be desirable. Therefore, a simultaneous treatment with food-grade enzymes (Ultraflo® L or Viscozyme® L) and high hydrostatic pressure (HHP) was used to improve LMWC profile. Release of LMWC from Okara was monitored and estimated using a newly calibrated and validated HPLC method with an ion-exchange column and evaporative light scattering detection (HPLC-ELSD). Both enzymes improved the effect of the HHP treatment. Treatment at 600MPa, 40°C for 30min achieved a decrease in the average molecular weight of polysaccharides from 12.74±3.97kDa to 3.85±1.33 or 1.59±0.40kDa when Ultraflo® L or Viscozyme® L were used, respectively. Ultraflo® L (15min) and Viscozyme® L (30min) at 600MPa, were the most effective treatments.Using industrial by-products as a source of nutraceuticals is interesting from an economical point of view. The content of low molecular weight polysaccharides of Okara has been maximized to increase its value as a prebiotic. An industrial adapted treatment with high hydrostatic pressure assisted by food-grade enzymes has been employed. In addition, a new HPLC-ELDS method has been calibrated for monitorizating the process.