8 - Instant controlled pressure drop as new intensification ways for vegetal oil extraction

Abstract

Solvent extraction (SE) of plant-based ingredients is a crucial process in food and pharmaceutical industries. Different studies have aimed to increase the procedure efficiency, reduce the production cost, and improve the environmental aspect. They separately used the well known instant controlled pressure drop (DIC) texturing as a controlled plant pretreatment, and the ultrasound (US) technology during the solvent interaction process. The DIC modification of the plant structure improves the technological aptitude of the grain throughout higher solvent diffusivity issued from greater porosity and tortuosity with possibly more broken-wall cells. Moreover, the use of US allows improving the properly said SE process. By phenomenologically modeling oil SE kinetics using the NER (Neglected External Resistance), conditions to integrate the washing diffusion model, a constant effective diffusivity Deff was obtained. This reveals that the main US impact was to create a permanent microagitation of the solvent within the pore possibly without significantly generating along 160-min extraction time exploded cells by cavitation effects. This experimental and modeling study proved the synergetic impacts that DIC as texturing technology and US as assisting SE operation can trigger. Moreover, DIC treatment was proved to be much more effective compared to expanding. Another low-temperature DIC treatment performed under various cycles can also be used for deodorization, decontamination, etc. By dropping the pressure toward a primary vacuum of about 3–5kPa, DIC has concerned a large range of starch-free products even thermally sensitive materials, which can be effectively expanded with a completely controlled manner. Most existing conventional flash depressurization processes of texturing operations such as puffing, cooking/extrusion, expanding, and steam explosion require up to four times higher saturated-dry steam pressure and are up to twice more expensive for poorer performance and too limited to starch-based materials.