Puffing pretreatment process is that, in a wet and hot state, quickly make material flake pass through the outlet of extrusion puffing machine, and make the material temperature increases rapidly from 88-110℃, moisture of soybean flake is 10-12%, of cottonseed kernel is 7.5-12%, rice bran puffing grains temperature can reach 130℃ in the outlet.
Through the puffing pretreatment process, the effect of lipase on the quality of oil is deactivated at wet and humid temperatures, the inactivation rate of enzyme has been reached above 95%. Through puffing pretreatment, the extracted flake volume-weight is increased from 400kg/m³to 600kg/m³. It is beneficial to wetting and eliminating the solvent because the evaporation of the puffing particles moisture forms micropores and increases the specific surface area of the solvent contact.
After puffing pretreatment, the volume-weight of raw flake is increased, while the solvent content in wet meal is significantly lower, the puffed material is with highly improved permeability and filtration performance compared with the raw flake, so the extracting rate of puffed material particle can be improved.