Aqueous Enzymatic Extraction of Rapeseed Oil and Protein from Dehulled Cold-pressed Double-low Rapeseed Cake

Abstract

Abstract The oil and protein of dehulled cold-pressed double-low rapeseed cake was extracted by an aqueous enzymatic process. The rapeseed cake was treated by the chosen combined enzymes of Viscozyme L and Alcalase 2.4L (VLA,1:1,w/w). Preliminary experiments and Response Surface Methodology (RSM) were used to study the effects of enzyme concentration, incubation time and water-to-cake ratio on the extraction yield of oil and protein. This is how the desirable conditions were obtained. Transmissive electron microscope photo showed that after cold-pressing the cell structure of rapeseed was partly damaged while dehulling had little effect on the cell structure of rapeseed. In RSM experiments water-to-cake ratio showed significant effects on the extraction of oil and protein (P<0.05),while incubation time only showed significant effects on protein yield (P<0.05).The desirable conditions were as follows: 1.0% concentration (w/w) of VLA; water-to-cake ratio(w/w),6:1; 80 min incubation time. Under this condition, the extraction yield of protein and oil were 82.10% and 71.89%, respectively. Through combining both the cold-press and the aqueous enzymatic processes together, the total oil yield reached 91.6%, which is higher than the normal cold-press process or the aqueous enzymatic extraction process alone.