Ethanol extraction of canola oil: Kinetics and effects of type of solvent and microwave-pretreatment☆

Abstract

The phenomenon and kinetics of the ethanol extraction of canola oil from microwave-pretreated seeds was studied using a Fick’s diffusion model. The extraction was performed in a batch system at constant temperature (313–333 K) at different times (300–64 800 s); then the total solvent-free extracts (SFE) were washed with hexane, obtaining oil as a hexane-soluble fraction (HSE) along a hexane-insoluble fraction. The values of the fitted parameters were different from those obtained by hexane extraction, showing an influence of the solvent on the kinetic parameters. A comparison of SEM images of pre-extracted, post-extracted with ethanol and post-extracted with hexane meals showed a dilution of the structural matrix with ethanol, not observed in post-extraction samples with hexane. This would indicate that a microwave-pretreatment is not necessary for the ethanol extraction of canola oil under the studied conditions, although it is important for breaking seed structures to facilitate the conventional extraction with hexane.

Keywords

• canola oil
• ethanol
• kinetics
• microwave