What Are the Methods of Canola Oil & Rapeseed Oil Production?

Rapeseed oil production is obtained in two methods - by pressing or extraction. For each method, the seed must be fragmented and prepared for processing. Finally, it is refined using water precipitation and organic acid to remove gums and free fatty acids, filtering to remove color, and deodorizing using steam distillation. Canola/rapeseed at this point oil is ready to be packaged and sold as cooking oil, or further processed into a wide range of consumer and commercial products.

1. Pressing - mechanical fat extraction in a press. Chemicals are not used in the process. The seeds are crushed in a screw press, rubbed into a pulp and the extracted oil passes through filters, on which residues are retained. The oil obtained via this process is of high quality. Pressing can be done in two ways:

Cold method - oils obtained mechanically at a controlled temperature - cold-pressed oils - discharge temperature maintained at a level no higher than 50° C. The most expensive method of obtaining oils. The oil obtained is rich in unsaturated fatty acids, has an intense color and smell. Because it does not contain a preservative it should be quickly used up.

Hot method - involves the production of oil at a temperature of 160 - 200° The yield of seeds of oil plants doubles, but the unsaturated fatty acids are changed into unfavorable trans-isomers.

2. Chemical (extraction) - isolation of oil with chemical solvents (most often with hexane), while heating up to high temperatures (over 100° C). This is the most efficient and cheapest method of obtaining oil, however, it deprives the raw material of valuable nutrients and leaves traces of chemical solvent, therefore it is not recommended in food. Currently, extraction is more often preceded by pressing. After receiving the oil, the next stage is the refining or purification stage (it is not obligatory).