Technology for extraction of perilla seed oil from pressed perilla seed cake with ethanol

To investigate the possibility of using ethanol solution for vegetable oil extraction, the process of solvent extraction of dehulled perilla seed cake obtained from the mechanical press at low temperature was studied. Effects of extraction times, solid to solvent ratio and concentrations of ethanol solution on content of residual oil, protein, tannin and phytic acid in meal were determined by single factor experiments carried out at 78℃. Optimized condition of solvent extraction obtained from orthogonal experiment was using 90% (m/m) ethanol solution as solvent to perform extraction at the solid to solvent ratio of 1︰2.5 for 6 times. The content of residual oil, protein (N×6.25, in dry weight), tannin and phytic acid in meal obtained from the optimized process were 0.46%, 50.5%, 1.7% and 6.01%, respectively. A phase separation phenomenon of the miscella with the oil content up to 1% was observed. When the miscella was chilled to 5℃ for 24 h, the oil content of light phase and heavy phase were less than 3% and more than 90%, respectively. Recovery of solvent will benefit from the chilling operation of miscella. Therefore, ethanol solution is a promising solvent for vegetable oil extraction, but further research is needed to promote this solvent into industrial application.