Cooking oil
Cooking oil is also used in food preparation and flavoring not involving heat, such as salad dressings and bread dips.
Growth at colder temperatures tends to result in higher levels of omega-3 fatty acids in seed oils.
In the US, trans fats are no longer "generally recognized as safe", and cannot be added to foods, including cooking oils, without special permission.
[31] Those oils with higher linolenic fractions are avoided due to polymerization or gumming marked by increases in viscosity with age.
[citation needed][33] In a cool, dry place, oils have greater stability, but may thicken, although they will soon return to liquid form if they are left at room temperature.
To minimize the degrading effects of heat and light, oils should be removed from cold storage just long enough for use.
[24] High oleic acid oils include almond, macadamia, olive, pecan, pistachio, and high-oleic cultivars of safflower and sunflower.
[54] The flash point is the temperature at which oil vapors will ignite but are not produced in sufficient quantities to stay lit.
Cold-pressed oils are extracted under a controlled temperature setting usually below 105 °C (221 °F) intended to preserve naturally occurring phytochemicals, such as polyphenols, tocotrienols, plant sterols and vitamin E which collectively affect color, flavor, aroma and nutrient value.
Refinement then alters the appearance, texture, taste, smell, or stability of the oil to meet buyer expectations.
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.
[105] 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.
The proper way to dispose of oil is to put it in a sealed non-recyclable container and discard it with regular garbage.
It can be used in animal feed, soap, make-up, clothes, rubber, detergents, directly as fuel, and to produce biodiesel.
[114] Grease traps or interceptors collect fats and oils from kitchen sinks and floor drains.
[115] In Kenya, thieves sell stolen electric transformers to operators of roadside food stalls for reuse of the oil in deep frying, suitable for prolonged use longer than regular cooking oil, but a threat to consumer health due to the presence of PCBs and polycyclic aromatic hydrocarbons.
