Dewaxing (also called winterization) of sunﬂower oil is essential when the oil is to be used as salad oil. The presence of wax makes the oil appear cloudy at room temperature. The oil normally becomes cloudy in 5–6h but with proper dewaxing the oil remains clear after 24h of storage at 0˚C.
The following steps are used to dewaxing sunﬂower oil:
1.Crude oil is reﬁned and bleached to low phosphorus (<1ppm) and low moisture content (<0.1%).
2.The oil is heated to 55˚C to make sure the oil is fully liquid.
3.The oil is cooled slowly to 7–8˚C.
4.Cooled oil is held in a specially insulated tank with a special slow-speed mechanical agitator.
5.Preferably, the oil is held for 12–24h at this temperature.
6.The oil is mixed with diatomaceous earth/filter aid through an in-line mixing system and filtered through a pressure leaf filter pre-coated with diatomaceous earth/filter aid.
7.The filtered oil is collected, checked for cold test and filterable impurities, and then deodorized.
8.The deodorized oil is checked again for cold test along with the other analyses listed earlier.