OIL. Oil is liquid fat, usually plant-derived, used as a cooking medium, as a lubricant to keep food from sticking to pans, and as a source of flavor. Oil from animal sources, particularly fish oil, is also used as a nutritional supplement. Oil is also ubiquitous in processed foods.

The difference between oil and fat is that oil is liquid at room temperature while fat is solid. Chemically, both are composed of hydrocarbon chains and are potent sources of energy. The strong molecular bonds of fats and oils make them relatively resistant to heat and thus suitable for high-heat cooking methods such as deep-frying. Oil can be used in conjunction with other fats, such as butter, to raise the temperature of the other fat at which it would otherwise begin to break down and smoke.

History of Oil

Olive oil and sesame oils are among the most ancient oils in...