<Li> Deodorizing, by treating with high - heat pressurized steam to evaporate less stable compounds that might cause "unusual" odors or tastes . </Li> <Li> Preservative addition, such as BHA and BHT to help preserve oils that have been made less stable due to high - temperature processing . </Li> <P> Filtering, a non-chemical process which screens out larger particles, could be considered a step in refinement, although it doesn't alter the state of the oil . </P> <P> Most large - scale commercial cooking oil refinement will involve all of these steps in order to achieve a product that's uniform in taste, smell and appearance, and has a longer shelf life . Cooking oil intended for the health food market will often be unrefined, which can result in a less stable product but minimizes exposure to high temperatures and chemical processing . </P>

Another word for a fat or oil is due to its three part structure