Pilot-Plant Proof-of-Concept for Integrated, Countercurrent, Two-Stage, Enzyme-Assisted Aqueous Extraction of Soybeans

Proof-of-concept for integrated, countercurrent, two-stage, enzyme-assisted aqueous extraction processing of soybeans was demonstrated on a pilot-plant scale (75 kg extruded flaked soybeans) where the protease used to demulsify the cream was recycled into upstream extraction stages. Oil, protein, and solids extraction yields of 98.0 +/- A 0.5%, 96.5 +/- A 0.4%, and 86.8 +/- A 0.5% were achieved by using the integrated countercurrent process. A three-phase horizontal decanter centrifuge efficiently separated the solids from the two liquid fractions (skim and cream). Fine separation between the two liquid fractions was important to reducing the volume of skim contaminating the cream fraction, thereby reducing the amount of enzyme used for cream demulsification and subsequent extraction. We were able to reduce enzyme use when moving from the laboratory to the pilot-plant scale, which reduced the degree of protein hydrolysis and improved cream demulsification. Enzyme-catalyzed cream demulsification was 91.6% efficient and 93.0% free oil recovery from cream was achieved by using the integrated approach.