Winterization

The term winterization implies that the oil is subjected to cold temperature in order to separate some amount of solids and then separate the solids from the liquid fraction . The solids are removed via filtration . The liquid fraction thus obtained is used as cooking oil, salad oil, and also for formulation of margarine and shortening. Winterization process removes waxes from sunflower oil, safflower oil. Canola oil, and corn oil.
Crude sunflower oil may contain 300-400 PPM of wax oil expelled from well corticated seeds, and this can be much higher and can be up to 2000 PPM if the seeds are not properly decorticated.

The wax content in sunflower oil is reduced through the winterization process. In this process the oil is heated at first to ensure that all of the waxes are completely melted. The oil is then chilled under controlled cooling rate. This separate the waxes from the Oil , which is then separated from the rest of the oil though filtration.