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'Cooking oil' is purified fat of plant or animal origin, which is liquid at room temperature.
Some of the many different kinds of edible vegetable oils include: olive oil, palm oil, soybean oil, canola oil, pumpkin seed oil, corn oil, sunflower oil, safflower oil, peanut oil, grape seed oil, sesame oil, argan oil and rice bran oil. Many other kinds of vegetable oils are also used for cooking.
The generic term "vegetable oil" when used to label a cooking oil product refers to a blend of a variety of oils often based on palm, corn, soybean or sunflower oils.
Oil can be flavoured by immersing aromatic food stuffs such as fresh herbs, peppers and so forth in the oil for an extended period of time. However, care must be taken when using garlic and onions to prevent the growth of ''Clostridium botulinum'' (the bacterium which causes botulism) in this medium.

Contents

Health and nutrition

Storing and keeping oil

Types of oils and their characteristics

Waste cooking oil

Notes and References

Other references

External link

Health and nutrition

Fats are an essential nutrient in the human diet, but an unbalanced diet is not healthy. For most individuals, it is appropriate to get 30% of one's daily food energy from fats and oils, which is recommended to ''not'' be evenly divided between monounsaturated, polyunsaturated, and saturated fats as the FDA recommends that ''less'' than 10% of a day's worth of calories should come from saturated fats.^[1]
Cooking oil is a special problem, as hydrogenation of oils makes them more stable, but also creates trans fats which are unhealthy.
Animal products (dairy and lard) can create trans fats for certain usage however the traces of trans fat from animals and other products which have saturated fats are significantly less than the concentration found in oils that has been through hydrogenation and isn't hazardous when consumed normally in a balanced diet. Coconut oil is an exception to the idea.
Some hydrogenation of oils occurs during cooking, causing normally healthy unsaturated fats like olive oil to convert to trans fats. But in non-industrial settings this process does not occur at appreciable quantities.^[2]
Many cooking oils are known sources of various vitamins (A and E), minerals, amino acids, essential fatty acids, and antioxidants.
Peanut and cashew oils and nut-based oils may present a hazard to persons with a nut allergy. A severe allergic reaction may cause anaphylactic shock and result in death.

Storing and keeping oil

Whether refined or not, all oils are sensitive to heat, light and exposure to oxygen. Rancid oil has an unpleasant aroma and acrid taste, and its nutrient value is greatly diminished. To delay the development of rancid oil, a blanket of an inert gas, usually nitrogen, is applied to the vapor space in the storage container immediately after production. This is referred to as tank blanketing.
It is best to store all oils in the refrigerator or a cool, dry place. Oils may thicken, but if you let them stand at room temperature they will soon return to liquid. To prevent negative effects of heat and light, take oils out of cold storage just long enough to use them. Refined oils high in monounsaturated fats keep up to a year, while those high in polyunsaturated fats keep about six months. Extra-virgin and virgin olive oils keep about a year after opening. Olive and other monounsaturated oils keep well up to eight months; unrefined polyunsaturated oils only about half as long.
Some comparisons have been made to vegetable oil relating to its biomass.

Types of oils and their characteristics

''Saturated'' fats are unhealthy in excess, but the consumption of small amounts of these oils is essential. ''Unsaturated'' fats (monounsaturated, polyunsaturated) are generally healthier for those consuming Western-style diets. Nutrition experts recommend that no more than 30% of a Western-style diet be composed of fats. In extremely cold environments, a diet that is up to two-thirds fat is acceptable and can, in fact, be critical to survival in that type of environment.

Type of Oil or Fat	Saturated fat	Monounsaturated fat	polyunsaturated	Smoke Point[3]	Uses
Butter	66%	30%	4%	150 °C (302 °F)	cooking, baking, condiment, sauces, flavoring
Ghee, clarified butter	65%	32%	3%	190 °C (374 °F)	deep frying, cooking, sautéeing, condiment, flavoring
Canola oil	6%	62%	32%	238 °C (460 °F)	frying, baking, salad dressings
Coconut oil	92%	6%	2%	177 °C (350 °F)	commercial baked goods, candy and sweets, whipped toppings, nondairy coffee creamers, shortening
Corn oil	13%	25%	62%	236 °C (457 °F)	frying, baking, salad dressings, margarine, shortening
Cottonseed oil	24%	26%	50%	216 °C (420 °F)	margarine, shortening, salad dressings, commercially fried products
Grape seed oil	12%	17%	71%	204 °C (400 °F)	cooking, salad dressings, margarine
Lard	41%	47%	12%	138-201 °C (280-395 °F)[4]	baking, frying
Margarine, hard	80%	14%	16%	150-160 °C (300-320 °F)	cooking, baking, condiment
Margarine, soft	20%	47%	33%	150-160 °C (300-320 °F)	cooking, baking, condiment
Diacylglycerol (DAG) oil	3.5%	37%	59%	215 °C (420 °F)	frying, baking, salad oil
Olive Oil, Extra Virgin	14%	73%	11%	207 °C (406 °F)	cooking, salad oils, margarine
Olive Oil, Virgin	14%	73%	11%	215 °C (420 °F)	cooking, salad oils, margarine
Olive Oil, Refined	14%	73%	11%	225 °C (438 °F)	Sautee, Stir frying, cooking, salad oils, margarine
Olive Oil, Extra Light	14%	73%	11%	242 °C (468 °F)	Sautee, Stir frying, frying, cooking, salad oils, margarine
Palm oil	52%	38%	10%	230 °C (446 °F)	cooking, flavoring, vegetable oil, shortening
Peanut oil	18%	49%	33%	231 °C (448 °F)	frying, cooking, salad oils, margarine
Safflower oil	10%	13%	77%	265 °C (509 °F)	cooking, salad dressings, margarine
Sesame oil unrefined	14%	43%	43%	177 °C (350 °F)	cooking, deep frying
Sesame oil semi-refined	14%	43%	43%	232 °C (450 °F)	cooking, deep frying
Soybean oil	15%	24%	61%	241 °C (466 °F)	cooking, salad dressings, vegetable oil, margarine, shortening
Sunflower oil	11%	20%	69%	246 °C (475 °F)	cooking, salad dressings, margarine, shortening

There is a general lack of consensus on the smoke points of many popular oils, as well as a lack of standardization for qualifiers such as "refined". Empirical tests are heavily dependent on the qualities of the particular samples (brand, composition, process) available, but appear to be the major source of available data. In the field, experience trumps references, and there is no source that seems truly authoritative. A crude guide is that lighter, more refined oils have higher smoke points. If there is any doubt at all, be fully prepared to extinguish a burning oil fire before heating.

Waste cooking oil

Proper disposal of used cooking oil is an important waste-management concern. Oil is lighter than water and tends to spread into thin and broad membranes which hinder the oxygenation of water. Because of this, a single liter of oil can contaminate as much as 1 million liters of water.^[5] Also, oil can congeal on pipes provoking blockages.
Because of this, cooking oil should never be dumped on the kitchen sink or in the toilet bowl. The proper way to dispose of oil is to put it in a sealed non-recyclable container and discard it with regular garbage.^[6]
Better yet, cooking oil can be recycled. It can be used to produce soap and biodiesel.^[7]

Notes and References

1. FDA Consumer The Food Pyramid Retrieved September 18, 2006
2. Olive Oil Source Cooking with Olive Oil Retrieved December 12, 2006
3.
The smoke point of margarine varies depending on the types of oils used in its formulation, but can be generally assumed to be similar to that of butter.

4.
The smoke point of oils depends primarily on their free fatty acid content (FFA) and molecular weight. Through repeated use, as in a deep fryer, food residues or by-products of the cooking process will accumulate within the oil and lower its smoke point. The values shown in the above table must therefore be taken as approximate, and are not suitable for accurate or scientific use.
5. Natureba — Educação Ambiental. Tips to avoid water waste and to require the preservation of hydro-resources [1] Retrieved August 5, 2007
6. NYC Department of Environmental Protection. Grease Disposal Tips to Help the City's Environment [2] Retrieved August 5, 2007
7. CDM — Executive Board. Production of biodiesel based on waste oils and/or waste fats
from biogenic origin for use as fuel. [3] Retrieved August 5, 2007

Other references

★ O'Brien, R.D. (1998). ''Fats and Oils: Formulating and Processing for Applications.'' Lancaster, PA: Technomic Publishing Co., Inc.

★ Potter, N.N. and J.H. Hotchkiss (1995). ''Food Science - Fifth Edition.'' New York: Chapman & Hall. pp. 359-80, 402-7.

External link

★ American Oil Chemical Society official website