cottonseed oil

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Cottonseed oil is a cooking oil extracted from the seeds of cotton plant of various species, mainly Gossypium hirsutum and Gossypium herbaceum. Cotton grown for oil extraction is one of the big four genetically modified crops grown around the world, next to soy, corn, and rapeseed (canola).^[1]

The cottonseed has a similar structure to other oilseeds such as sunflower seed, having an oil bearing kernel surrounded by a hard outer hull; in processing, the oil is extracted from the kernel. Cottonseed oil is used for salad oil, mayonnaise, salad dressing, and similar products because of its flavor stability.^[2] The cottonseed oil undergoes intensive treatment after extraction to reduce the level of gossypol found in untreated cottonseed oil, the consumption of which may produce undesirable side-effects.^[3]

Chemical composition of cottonseed oil

Its fatty acid profile generally consists of 70% unsaturated fatty acids including 18% monounsaturated (oleic), 52% polyunsaturated (linoleic) and 26% saturated (primarily palmitic and stearic).^[4]

Cottonseed oil is described by scientists as being "naturally hydrogenated" because the saturated fatty acids it contains are the natural oleic, palmitic, and stearic acids. These fatty acids make it a stable frying oil without the need for additional processing or the formation of trans fatty acids . Cottonseed oil is not required to be as fully hydrogenated for many purposes as some of the more polyunsaturated oils. On partial hydrogenation, the amounts of monounsaturated fatty acids actually increase. When hydrogenated to a typical Iodine Value of about 80, for example, its fatty acid profile shifts to 50% monounsaturated, 21% polyunsaturated, and 29% saturated, which are all well within current diet/health guidelines.^[2]

Gossypol is a biologically-active yellow polyphenolic compound produced by cotton and other members of the order Malvaceae, such as okra.^[5] This coloured compound found in tiny glands in the seeds, leaf, stem, tap root bark, and root of the cotton plant. The adaptive function of the compound is believed to be one of facilitating insect resistance.

The three key steps of refining, bleaching and deodorization that are involved in producing finished oil act to reduce the gossypol level. Ferric chloride, a chemical relative to chlorine that is also used to in sewage treatment, is often used to decolorize cottonseed oil.^[6]

Health concerns regarding cottonseed oil

Cottonseed oil is high on the hit list for many nutritionists, who deem it too high in saturated fat and too low in monounsaturated fat.^[7] Detractors say that cottonseed oil may contain natural toxins and unacceptably high levels of pesticide residues; cotton is not classified as a food crop, and farmers use many agrichemicals when growing it.^[8]. Cottonseed oil has traditionally been used in recognizably fatty foods such as potato chips and is a primary ingredient in Crisco, the shortening product.^[9]But since it is significantly less expensive than olive oil or canola oil, cottonseed has started to creep into a much wider range of processed foods, including cereals, breads and snack foods. Products that say "may contain one or more of these oils" and list cottonseed, virtually always contain it.^[10] Cottonseed oil resists rancidity and therefore offers a longer shelf life for food products in which it is an ingredient.

Physical properties

Once processed, cottonseed oil has a mild taste and appears generally clear with a light golden color, the amount of color depending on the amount of refining.^[11] Cottonseed oil has a relatively high smoke point as a frying medium. Like other long-chain fatty acid oils, cottonseed oil has a smoke point of about 450 degrees Fahrenheit.^[5] Cottonseed oil is high in tocopherols which also contribute to its stability giving products that contain it a long shelf life, hence manufacturers' proclivity to use it in packaged goods.

Use as a food

1. As a cooking oil, it is used for frying in commercial cooking. It is often a primary ingredient in shortening and margarine.^[2]
2. Cottonseed oil is one of the most common oils in commercial frying in the production of potato and corn chips.^[2][5]
3. Cottonseed oil is used as cocoa butter substitutes after hydrogenation and/or fractionation.^[2][5]
4. Hydrogenated cottonseed oil is used in frozen desserts to replace more expensive butter fat.^[5]

References

1. ^ "Reports on GM Canola". http://www.dpi.vic.gov.au/dpi/nrensr.nsf/LinkView/AE641E63162D0A50CA256ECA000A8B123A8D6D972510B1ED4A2567C40015A7EE.  from the Australian Department of Primary Industries
2. ^ ^{a b c d e} Twenty Facts About Cottonseed Oil. National Cottonseed Products Association.
3. ^ "Low potassium levels from use of Gossypol linked to paralysis". International Family Planning Perspectives 7 (1): 24–25. 1981. "Gossypol, a male antifertility agent derived from the cotton plant, may be the cause of hypokalemic paralysis in a small but significant proportion of its users.". 
4. ^ Cottonseed Oi Use. NTOK Cotton (North Texas, Oklahoma, and Kansas cotton industry partnership).
5. ^ ^{a b c d e} Jones, Lynn A.; King, C. Clay (1996). "Cottonseed oil". in Y. H. Hui (ed.). Bailey's Industrial Oil and Fat Products, Edible Oil and Fat Products: Oils and Oilseeds. New York: Wiley. ISBN 978-0-471-59426-0. 
6. ^ [1]Research abstract: Southern Regional Research Laboratory
7. ^ [2]Dr. Weil: Why you should avoid cottonseed oil
8. ^ [3]Article: The Awful Truth About Cottonseed Oil
9. ^ [4]Crisco.com: Ingredient facts
10. ^ [5]Cotton 24/7: Cottonseed oil use on the rise
11. ^ [6]Cottonseed oil website of the National Cottonseed Products Association.