Corn oil

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Corn oil, in a 5-liter plastic bottle
Corn oil, plastic jugs in cardboard boxes, 33 lbs. each

Corn oil (maize oil) is oil extracted from the germ of corn (maize). Its main use is in cooking, where its high smoke point makes refined corn oil a valuable frying oil. It is also a key ingredient in some margarines. Corn oil is generally less expensive than most other types of vegetable oils. One bushel of corn contains 1.55 pounds of corn oil (2.8% by weight). Corn agronomists have developed high-oil varieties; however, these varieties tend to show lower field yields, so they are not universally accepted by growers.

Corn oil is also a feedstock used for biodiesel. Other industrial uses for corn oil include soap, salve, paint, rustproofing for metal surfaces, inks, textiles, nitroglycerin, and insecticides. It is sometimes used as a carrier for drug molecules in pharmaceutical preparations.

Production

Almost all corn oil is expeller-pressed, then solvent-extracted using hexane or 2-methylpentane (isohexane).[1] The solvent is evaporated from the corn oil, recovered, and re-used. After extraction, the corn oil is then refined by degumming and/or alkali treatment, both of which remove phosphatides. Alkali treatment also neutralizes free fatty acids and removes color (bleaching). Final steps in refining include winterization (the removal of waxes), and deodorization by steam distillation of the oil at 232–260 °C (450–500 °F) under a high vacuum.[1]

Some specialty oil producers manufacture unrefined, 100%-expeller-pressed corn oil. This is a more expensive product since it has a much lower yield than the combination expeller and solvent process, as well as a smaller market share.

Constituents and comparison

Vegetable oils
Type Processing
Treatment
Saturated
fatty acids[2]
Mono-
unsaturated
fatty acids[2]
Polyunsaturated fatty acids Oleic acid
(ω-9)
Smoke point
Total poly[2] linolenic acid
(ω-3)
Linoleic acid
(ω-6)
Avocado   11.560 70.554 13.486 1 12.5   480 °F (249 °C)[3]
Canola (rapeseed)   7.365 63.276 28.142 10 10   400 °F (204 °C)[4]
Coconut   91.000 6.000 3.000   2 6 350 °F (177 °C)[4]
Corn[5]   12.948 27.576 54.677 1 58 28 450 °F (232 °C)
Cottonseed   25.900 17.800 51.900 1 54 19 420 °F (216 °C)[5]
Flaxseed/Linseed (European)[6]   7.500 15.500 79.000 64 15 11 225 °F (107 °C)
Olive   14.000 72.000 14.000 1.5 15   380 °F (193 °C)[4]
Palm   49.300 37.000 9.300   10 40 455 °F (235 °C)
Peanut   16.900 46.200 32.000   32 48 437 °F (225 °C)[5]
Safflower (>70% linoleic)   8.000 15.000 75.000       410 °F (210 °C)[4]
Safflower (high oleic)   7.541 75.221 12.820       410 °F (210 °C)[4]
Soybean   15.650 22.783 57.740 7 50 24 460 °F (238 °C)[5]
Sunflower (<60% linoleic)   10.100 45.400 40.100 0.2 39.8 45.3 440 °F (227 °C)[5]
Sunflower (>70% oleic)   9.859 83.689 3.798       440 °F (227 °C)[5]
Cottonseed (hydrogenated)[2] Hydrogenated 93.600 1.529 0.587   0.287  
Palm (hydrogenated) Hydrogenated 47.500 40.600 7.500      
Soybean (hydrogenated)[2] Hydrogenated 21.100 73.700 0.400 0.096    
Values as percent (%) by weight of total fat.

Effects on health

Some medical research suggests that excessive levels of omega-6 fatty acids, relative to omega-3 fatty acids, may increase the probability of a number of diseases and depression.[8][9][10] Modern Western diets typically have ratios of omega-6 to omega-3 in excess of 10 to 1, some as high as 30 to 1, partly due to corn oil which has an omega-6 to omega-3 ratio of 49:1. The optimal ratio is thought to be 4 to 1 or lower.[11][12]

A high intake of omega-6 fatty acids may increase the likelihood that postmenopausal women will develop breast cancer.[13] Similar effects were observed on prostate cancer.[14] Other analysis suggested an inverse association between total polyunsaturated fatty acids and breast cancer risk.[15]

See also

References

  1. 1.0 1.1 Corn Refiners Association. Corn Oil 5th Edition. 2006
  2. 2.0 2.1 2.2 2.3 2.4 2.5 Lua error in package.lua at line 80: module 'strict' not found. All values in this column are from the USDA Nutrient database unless otherwise cited.
  3. What is unrefined, extra virgin cold-pressed avocado oil?, The American Oil Chemists’ Society
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  6. Fatty acid composition of important plant and animal fats and oils (German) 21 December 2011, Hans-Jochen Fiebig, Münster
  7. Scheda tecnica dell'olio di palma bifrazionato PO 64 (Italian)
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Further reading

  • Lua error in package.lua at line 80: module 'strict' not found.

External links