Cooking oil

Plant oils
Olive oil from Oneglia.jpg
Olive oil
Types
Vegetable fats (list)
Macerated (list)
Uses
Drying oil - Oil paint
Cooking oil
Fuel - Biodiesel
Components
Saturated fat
Monounsaturated fat
Polyunsaturated fat
Trans fat

Cooking oil is purified fat of plant origin, which is usually liquid at room temperature (saturated oils such as coconut and palm are more solid at room temperature than other oils).

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 may refer to a specific oil (such as rapeseed oil) or may refer to a blend of a variety of oils often based on palm, corn, soybean or sunflower oils.

Oil can be flavored by immersing aromatic food stuffs such as fresh herbs, peppers, garlic and so forth in the oil for a period of time. However, care must be taken when storing flavored oils to prevent the growth of Clostridium botulinum (the bacteria that produces toxins that can lead to botulism).

Contents

Health and nutrition

Olive oil.jpg
Italian olive oil 2007.jpg
Sunflowerseed oil.jpg
Hot chill oil.jpg
Oil3.jpg

The appropriate amount of fat as a component of daily food consumption is the topic of some controversy. Some fat is required in the diet, and fat (in the form of oil) is also essential in many types of cooking. The FDA recommends that 30% or less of calories consumed daily should be from fat.[1] Other nutritionists recommend that no more than 10% of a person's daily calories come from fat.[2] In extremely cold environments, a diet that is up to two-thirds fat is acceptable and can, in fact, be critical to survival.

While consumption of small amounts of saturated fats is essential, meta-studies conducted by several scientists find high correlation between excessive amounts of such fats and coronary heart disease.[3][4] Mayo Clinic highlighted oils that are high in saturated fats include coconut, palm oil and palm kernel oil. Those of lower amounts of saturated fats, and higher levels of unsaturated (preferably monounsaturated) fats like olive oil, peanut oil, canola oil, avocado, safflower, corn, sunflower, soy, mustard and cottonseed oils are generally healthier.[5] The National Heart, Lung and Blood Institute[6] and World Heart Federation[7] have urged saturated fats be replaced with polyunsaturated and monounsaturated fats. The health body lists olive and canola oils as sources of monounsaturated oils while soybean and sunflower oils are rich with polyunsaturated fat. Results of research carried out in Costa Rica in 2005 suggest that consumption of non-hydrogenated unsaturated oils like soybean and sunflower are preferable to the consumption of palm oil.[8]

The labeling of the cholesterol content of foods on the basis of their total saturated fat content is unjustified because not all saturated fats have negative effects on cholesterol.[9] Palmitic acid in palm oil, does not behave like other saturated fats, and is neutral on cholesterol levels because it is equally distributed among the three “arms” of the triglyceride molecule.[10] Studies have indicated that palm oil consumption reduces blood cholesterol in comparison with other traditional sources of saturated fats such as coconut oil, dairy and animal fats.[11]

Saturated fat is required by the body and brain to function properly. In fact, one study in Brazil compared the effects of soybean oil to coconut oil (a highly saturated fat) and found that while both groups showed a drop in BMI, the soybean oil group showed an increase in overall cholesterol (including a drop in HDL, the good cholesterol). The coconut oil group actually showed an increase in the HDL:LDL ratio (meaning there was more of the good cholesterol), as well as smaller waist sizes (something that was not shown in the soybean oil group. See the abstract here.

In 2007, scientists Kenneth C. Hayes and Pramod Khosla of Brandeis University and Wayne State University have indicated that the focus of current research has shifted from saturated fats to individual fats and percentage of fatty acids (saturates, monounsaturates, polyunsaturates) in the diet. An adequate intake of both polyunsaturated and saturated fats is needed for the ideal LDL/HDL ratio in blood, as both contribute to the regulatory balance in lipoprotein metabolism.[12]

Oils high in unsaturated fats may help to lower "bad" LDL cholesterol and may also raise "good" HDL cholesterol, though these effects are still under study.

Peanut, cashew, and other nut-based oils may also present a hazard to persons with a nut allergy. A severe allergic reaction may cause anaphylactic shock and result in death.

Trans fats

Unlike other dietary fats, trans fats are not essential, and they do not promote good health.[13] The consumption of trans fats increases one's risk of coronary heart disease[14] by raising levels of "bad" LDL cholesterol and lowering levels of "good" HDL cholesterol.[15] Trans fats from partially hydrogenated oils are more harmful than naturally occurring oils.[16]

Several large studies[17][18][19][20] indicate a link between consumption of high amounts of trans fat and coronary heart disease and possibly some other diseases. The United States Food and Drug Administration (FDA), the National Heart, Lung and Blood Institute and the American Heart Association (AHA) all have recommended limiting the intake of trans fats.

Cooking with oils

Heating an oil changes its characteristics. Oils that are healthy at room temperature can become unhealthy when heated above certain temperatures. When choosing a cooking oil, it is important to match the oil's heat tolerance with the cooking method.[21]

A 2001 parallel review of 20-year dietary fat studies in the United Kingdom, the United States of America, and Spain[22] found that polyunsaturated oils like soya, canola, sunflower, and corn oil degrade easily to toxic compounds when heated. Prolonged consumption of burnt oils led to atherosclerosis, inflammatory joint disease, and development of birth defects. The scientists also questioned global health authorities’ recommendation that large amounts of polyunsaturated fats be incorporated into the human diet without accompanying measures to ensure the protection of these fatty acids against heat- and oxidative-degradation.

Palm oil contains more saturated fats than canola oil, corn oil, linseed oil, soybean oil, safflower oil, and sunflower oil. Therefore, palm oil can withstand the high heat of deep frying and is resistant to oxidation compared to highly unsaturated vegetable oils.[23] Since about 1900, palm oil has been increasingly incorporated into food by the global commercial food industry because it remains stable in deep frying or in baking at very high temperatures.[24][25] and for its high levels of natural antioxidants.[26]

Oils that are suitable for high-temperature frying (above 230 °C/446 °F) because of their high smoke point include:

Oils suitable for medium-temperature frying (above 190 °C/374 °F) include:

Unrefined oils should not be used for frying, but are safe for simmering.

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.

All oils should be kept in the refrigerator or a cool, dry place. Oils may thicken, they will soon return to liquid if they stand at room temperature. To prevent negative effects of heat and light, oils should be removed from cold storage just long enough for use. Refined oils high in monounsaturated fats keep up to a year (olive oil will keep up to a few years), while those high in polyunsaturated fats keep about six months. Extra-virgin and virgin olive oils keep at least 9 months after opening. Other monounsaturated oils keep well up to eight months, while unrefined polyunsaturated oils will keep only about half as long.

In contrast, saturated oils, such as coconut oil and palm oil, have much longer shelf lives and can be safely stored at room temperature.[27] Their lack of polyunsaturated content causes them to be more stable.[28]

Types of oils and their characteristics

Lighter, more refined oils tend to have higher smoke points. Experience using an oil is generally a sufficiently reliable guide. Although outcomes of empirical tests are sensitive to the qualities of particular samples (brand, composition, refinement, process), the data below should be helpful in comparing the properties of different oils.

Smoking oil indicates a risk of combustion, and left unchecked can also set off a fire alarm. When using any cooking oil, should it begin to smoke, heat should be reduced immediately. Generally, one should be fully prepared to extinguish a burning oil fire before heating, typically by having on hand the lid to place on the pan, or (for the worst case) having on hand the proper fire extinguisher.

Type of oil or fat Saturated Monounsaturated Polyunsaturated Smoke point Uses
Butter 66% 30% 4% 150 °C (302 °F) Cooking, baking, condiment, sauces, flavoring
Ghee, clarified butter 65% 32% 3% 190–250 °C (374–482 °F) Deep frying, cooking, sautéeing, condiment, flavoring
Canola oil 6% 62% 32% 242 °C (468 °F) Frying, baking, salad dressings
Coconut oil 92% 6% 2% 177 °C (351 °F) Commercial baked goods, candy and sweets, whipped toppings, nondairy coffee creamers, shortening
Rice bran oil 20% 47% 33% 254 °C (489 °F) Cooking, frying, deep frying, salads, dressings. Very clean flavoured & palatable.
Corn oil 13% 25% 62% 236 °C (457 °F) Frying, baking, salad dressings, margarine, shortening
Cottonseed oil 24% 26% 50% 216 °C (421 °F) Margarine, shortening, salad dressings, commercially fried products
Grape seed oil 12% 17% 71% 204 °C (399 °F) Cooking, salad dressings, margarine
Lard 41% 47% 2% 138–201 °C (280–394 °F)[29] Baking, frying
Margarine, hard 80% 14% 6% 150 °C (302 °F)[30] Cooking, baking, condiment
Margarine, soft 20% 47% 33% 150–160 °C (302–320 °F) Cooking, baking, condiment
Diacylglycerol (DAG) oil 3.5% 37.95% 59% 215 °C (419 °F) Frying, baking, salad oil
Olive oil (extra virgin) 14% 73% 11% 190 °C (374 °F) Cooking, salad oils, margarine
Olive oil (virgin) 14% 73% 11% 215 °C (419 °F) Cooking, salad oils, margarine
Olive oil (refined) 14% 73% 11% 225 °C (437 °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 (351 °F) Cooking
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 (linoleic) 11% 20% 69% 246 °C (475 °F) Cooking, salad dressings, margarine, shortening
Sunflower oil (high oleic)[31] 9% 82% 9%

Comparison to other types of food

Waste cooking oil

A bin for spent cooking oil in Austin, Texas, USA

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 litre of oil can contaminate as much as 1 million litres of water. Also, oil can congeal on pipes provoking blockages.[35]

Because of this, cooking oil should never be dumped in 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.[36]

Cooking oil can be recycled. It can be used to produce soap and biodiesel.[37]

See also

Notes and references

  1. ↑ "The Food Pyramid". FDA Consumer. http://www.cfsan.fda.gov/~dms/fdpyrmid.html. Retrieved 2006-09-18. 
  2. ↑ Dean Ornish, MD, Lifestyle Program
  3. ↑ Clarke, R; Frost, C; Collins, R; Appleby, P; Peto, R (1997). "Dietary lipids and blood cholesterol: quantitative meta-analysis of metabolic ward studies". BMJ (Clinical research ed.) 314 (7074): 112–7. PMID 9006469. 
  4. ↑ Mensink, RP; Zock, PL; Kester, AD; Katan, MB (2003). "Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: a meta-analysis of 60 controlled trials". The American journal of clinical nutrition 77 (5): 1146–55. PMID 12716665. 
  5. ↑ Dietary fats: Know which types to choose Mayo Clinic website
  6. ↑ Choose foods low in saturated fat National Heart, Lung, and Blood Institute (NHLBI), NIH Publication No. 97-4064. 1997.
  7. ↑ Diet & cardiovascular disease World Heart Federation website
  8. ↑ Kabagambe, Baylin, Ascherio & Campos (November 2005). "The Type of Oil Used for Cooking Is Associated with the Risk of Nonfatal Acute Myocardial Infarction in Costa Rica". Journal of Nutrition. pp. 2674–2679. http://jn.nutrition.org/cgi/content/abstract/135/11/2674. 
  9. ↑ Ng, TK; Hassan, K; Lim, JB; Lye, MS; Ishak, R (1991). "Nonhypercholesterolemic effects of a palm-oil diet in Malaysian volunteers". American Journal of Clinical Nutrition 53 (4): 1015S. PMID 2012009. http://www.ajcn.org/cgi/content/abstract/53/4/1015S. 
  10. ↑ A critical review of the cholesterolemic effects of palm oil Tony Ng Kock Wai, The United Nations University Press, Food and Nutrition Bulletin, Volume 15 (1993/1994), Number 2, June 1994
  11. ↑ Chong, YH; Ng, TK (1991). "Effects of palm oil on cardiovascular risk". The Medical journal of Malaysia 46 (1): 41–50. PMID 1836037. 
  12. ↑ Hayes, Kenneth C.; Khosla (2007). "The complex interplay of palm oil fatty acids on blood lipids". European Journal of Lipid Science and Technology 109: 453. doi:10.1002/ejlt.200700005. 
  13. ↑ Food and nutrition board, institute of medicine of the national academies (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academies Press. p. 423. http://www.nap.edu/openbook/0309085373/html/423.html. 
  14. ↑ Food and nutrition board, institute of medicine of the national academies (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academies Press. p. 504. http://darwin.nap.edu/books/0309085373/html/504.html. 
  15. ↑ "Trans fat: Avoid this cholesterol double whammy". Mayo Foundation for Medical Education and Research (MFMER).. http://www.mayoclinic.com/health/trans-fat/CL00032. Retrieved 2007-12-10. 
  16. ↑ Mozaffarian D, Katan MB, Ascherio A, Stampfer MJ, Willett WC (13 April 2006). "Trans Fatty Acids and Cardiovascular Disease". New England Journal of Medicine 354 (15): 1601–1613. doi:10.1056/NEJMra054035. PMID 16611951. http://content.nejm.org/cgi/content/full/354/15/1601.  PMID 16611951
  17. ↑ W.C. Willett, M.J. Stampfer, J.E. Mason, G.A. Colditz, F.E. Speizer, B.A. Rosner, L.A. Sampson, C.H. Hennekes, Intake of trans fatty acids and risk of coronary heart disease among women, Lancet 341, 581-585 (1993)
  18. ↑ F.B. Hu, M.J. Stampfer, J.E. Manson, E. Rimm, G.A. Colditz, B.A. Rosner, C.H. Hennekens, W.C. Willett, Dietary Fat Intake and the Risk of Coronary Heart Disease in Women, New England Journal of Medicine 337, 1491-1499 (1997) http://content.nejm.org/cgi/content/short/337/21/1491
  19. ↑ K. Hayakawa, Y.Y. Linko, P. Linko, The role of trans fatty acids in human nutrition, Journal of Lipid Science and Technology 102, 419-425 (2000)
  20. ↑ The Nurses' Health Study (NHS)
  21. ↑ Orna Izakson. "Oil right: choose wisely for heart-healthy cooking - Eating Right". E: the Environmental Magazine. http://findarticles.com/p/articles/mi_m1594/is_2_14/ai_98469943/pg_2. 
  22. ↑ Health effects of oxidized heated oils MARTIN GROOTVELD, CHRISTOPHER J.L. SILWOOD, PAUL ADDIS, ANDREW CLAXSON, BARTOLOMÉ BONET SERRA and MARTA VIANA, 2001, Foodservice Research International 13(1):41-55
  23. ↑ De Marco, Elena; Savarese; Parisini; Battimo; Falco; Sacchi (2007). "Frying performance of a sunflower/palm oil blend in comparison with pure palm oil". European Journal of Lipid Science and Technology 109: 237. doi:10.1002/ejlt.200600192. 
  24. ↑ Che Man, YB; Liu; Jamilah (1999). "Quality changes of RBD palm olein, soybean oil and their blends during deep-fat frying". Journal of Food Lipids 6 (3): 181–193. doi:10.1111/j.1745-4522.1999.tb00142.x. 
  25. ↑ Matthäus, Bertrand (2007). "Use of palm oil for frying in comparison with other high-stability oils". European Journal of Lipid Science and Technology 109: 400. doi:10.1002/ejlt.200600294. 
  26. ↑ Sundram, K; Sambanthamurthi, R; Tan, YA (2003). "Palm fruit chemistry and nutrition". Asia Pacific journal of clinical nutrition 12 (3): 355–62. PMID 14506001. http://apjcn.nhri.org.tw/server/APJCN/volume12/vol12.3/fullArticles/Sundram.pdf. 
  27. ↑ [1]
  28. ↑ [2]
  29. ↑ 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.
  30. ↑ 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.
  31. ↑ http://www.sunflowernsa.com/oil/default.asp?contentID=145
  32. ↑ 32.0 32.1 32.2 .nutritiondata.com --> Oil, vegetable, sunflower Retrieved on September 27, 2010
  33. ↑ 33.0 33.1 33.2 .nutritiondata.com --> Egg, yolk, raw, fresh Retrieved on August 24, 2009
  34. ↑ Feinberg School > Nutrition > Nutrition Fact Sheet: Lipids Northwestern University. Retrieved on August 24, 2009
  35. ↑ "Tips to avoid water waste and to require the preservation of hydro-resources". Natureba - Educação Ambiental. http://www.natureba.com.br/nature/saving-water.htm. Retrieved 2007-09-05. 
  36. ↑ "Grease Disposal Tips to Help the City's Environment". NYC Department of Environmental Protection. http://nyc.gov/html/dep/html/residents/congrease.shtml. Retrieved 2007-08-05. 
  37. ↑ "Production of biodiesel based on waste oils and/or waste fats from biogenic origin for use as fuel" (PDF). CDM - Executive Board. http://www.mct.gov.br/upd_blob/0016/16059.pdf. Retrieved 2007-09-05. 

Other references

External links

Edible fats and oils
Fats
Bacon fat · Blubber · Butter · Clarified butter · Cocoa butter · Dripping · Duck fat · Ghee · Lard · Margarine · Niter kibbeh · Salo · Schmaltz · Shea butter · Smen · Suet · Tallow · Vegetable shortening
Oils
Almond oil · Argan oil · Avocado oil · Canola oil · Cashew oil · Castor oil · Coconut oil · Colza oil · Corn oil · Cottonseed oil · Fish oil · Grape seed oil · Hazelnut oil · Hemp oil · Linseed oil (flaxseed oil) · Macadamia oil · Marula oil · Mongongo nut oil · Mustard oil · Olive oil · Palm oil (palm kernel oil) · Peanut oil · Pecan oil · Perilla oil · Pine nut oil · Pistachio oil · Poppyseed oil · Pumpkin seed oil · Rapeseed oil · Rice bran oil · Safflower oil · Sesame oil · Soybean oil · Sunflower oil · Tea seed oil · Walnut oil · Watermelon seed oil
See also: List of vegetable oils · Cooking oil · Essential oil