Olive oil has been a part of human culture for millennia.[4] Archaeological evidence shows that olives were turned into olive oil by 6000 BC[4] and 4500 BC in present-dayIsrael.[5] Pagnol, p. 19, says the 6th millennium inJericho, but cites no source.[citation needed] In ancient Egypt, plant oils including cedar oil, cypress oil, and olive oil were used during themummification process.[6]
Vegetable oils have been used as lighting fuel for lamps, cooking, medicine and lubrication.[citation needed]Palm oil has long been recognized in West and Central African countries, and European merchants trading with West Africa occasionally purchased palm oil for use as a cooking oil in Europe. It became highly sought-after commodity by British traders for use as an industrial lubricant for machinery during Britain'sIndustrial Revolution.[7]
Modern history
Palm oil formed the basis of soap products, such as Lever Brothers' (nowUnilever) "Sunlight", and B. J. Johnson Company's (nowColgate-Palmolive) "Palmolive,"[8] and by around 1870, palm oil constituted the primary export of some West African countries.[9]
In the United States,cottonseed oil was developed and marketed byProcter & Gamble as a creamed shortening –Crisco – as early as 1911.[10]Ginning mills were happy to have someone haul away the cotton seeds. The extracted oil was refined and partiallyhydrogenated to give a solid at room temperature and thus mimic natural lard, and canned under nitrogen gas. Compared to the rendered lard Procter & Gamble was already selling to consumers, Crisco was cheaper, easier to stir into a recipe, and could be stored at room temperature for two years without turning rancid.[citation needed]
Soybeans are protein-rich, and the medium-viscosity oil rendered from them was high in polyunsaturates.Henry Ford established a soybean research laboratory, developed soybean plastics and a soy-based synthetic wool, and built a car "almost entirely" out of soybeans.[11] Roger Drackett had a successful new product withWindex. He invested heavily in soybean research, seeing it as a smart investment.[12] By the 1950s and 1960s, soybean oil had become the most popular vegetable oil in the US; today it is second only topalm oil. In 2018–2019, world production was at 57.4 MT with the leading producers includingChina (16.6 MT),US (10.9 MT),Argentina (8.4 MT),Brazil (8.2 MT), andEU (3.2 MT).[13]
The early 20th century also saw the start of the use ofvegetable oil as a fuel indiesel engines and in heating oil burners.Rudolf Diesel designed his engine to run on vegetable oil. The idea, he hoped, would make his engines more attractive to farmers who had a source of fuel readily available. Diesel's first engine ran on its own power for the first time inAugsburg, Germany, on 10 August 1893 on nothing butpeanut oil. In remembrance of this event, 10 August has been declared "International Biodiesel Day".[14] The first patent on Biodiesel was granted in 1937.[15] Periodic petroleum shortages spurred research into vegetable oil as a diesel substitute during the 1930s and 1940s, and again in the 1970s and early 1980s when straight vegetable oil enjoyed its highest level of scientific interest. The 1970s also saw the formation of the first commercial enterprise to allow consumers to run straight vegetable oil in their vehicles. However,biodiesel, produced from oils or fats usingtransesterification is more widely used. Led by Brazil, many countries builtbiodiesel plants during the 1990s, and it is now widely available for use in motor vehicles, and is the most commonbiofuel in Europe today. In France, biodiesel is incorporated at a rate of 8% in the fuel used by all French diesel vehicles.[16]
In the mid-1970s, Canadian researchers developed a low-erucic-acid rapeseed cultivar. Because the word "rape" was not considered optimal for marketing, they coined the name "canola" (from "Canada Oil low acid"). The U.S.Food and Drug Administration approved use of the canola name in January 1985,[17] and U.S. farmers started planting large areas that spring. Canola oil is lower in saturated fats and higher in monounsaturates. Canola is very thin (unlike corn oil) and flavorless (unlike olive oil), so it largely succeeds by displacing soy oil, just as soy oil largely succeeded by displacing cottonseed oil.[citation needed]
The production of vegetable oils went up 125% between 2000 and 2020, driven by a sharp increase inpalm oil.[18]
Many vegetable oils are consumed directly, or indirectly as ingredients in food – a role that they share with someanimal fats, includingbutter,ghee,lard, andschmaltz. The oils serve several purposes in this role:
Shortening – as in giving pastries a crumbly texture.
Enriching – adding calories and satisfaction in consumption
Texture – altering how ingredients combine, especially fats and starches
Flavor base – oils can also "carry" flavors of other ingredients, such as peppers,[19] since many flavors are due to chemicals that are soluble in oil.
Oils can be heated to temperatures significantly higher than the boiling point of water, 100 °C (212 °F), and used tofry foods. Oils for this purpose must have a highflash point. Such oils include both the major cooking oils –soybean,rapeseed,canola,sunflower,safflower,peanut,cottonseed, etc. – and tropical oils, such ascoconut,palm, andrice bran. The latter are particularly valued in Asian cultures for high-temperature cooking, because of their unusually high flash points.
Industrial
Vegetable oils are used as an ingredient or component in many manufactured products.[citation needed]
Many vegetable oils are used to make soaps, skin products, candles, perfumes, and other personal care and cosmetic products. Some oils are particularly suitable asdrying oils, and are used in making paints and other wood treatment products. They are used inalkyd resin production. Dammar oil (a mixture of linseed oil anddammar resin), for example, is used almost exclusively in treating the hulls of wooden boats. Vegetable oils are increasingly being used in the electrical industry asinsulators as vegetable oils are not toxic to the environment,biodegradable if spilled and have highflash and fire points. However, vegetable oils are less stable chemically, so they are generally used in systems where they are not exposed tooxygen, and they are more expensive than crude oil distillate. Synthetic tetraesters, which are similar to vegetable oils but with four fatty acid chains compared to the normal three found in a natural ester, are manufactured byFischer esterification. Tetraesters generally have high stability to oxidation and have found use as engine lubricants. Vegetable oil is being used to produce biodegradablehydraulic fluid[20] andlubricant.[21]
One limiting factor in industrial uses of vegetable oils is that all such oils are susceptible to becomingrancid. Oils that are more stable, such asben oil ormineral oil, are thus preferred for industrial uses.Castor oil has numerous industrial uses, owing to the presence of ahydroxyl group on the fatty acid. Castor oil is a precursor toNylon 11. Castor oil may also be reacted withepichlorohydrin to make a glycidyl ether, which is used as a diluent and flexibilizer withepoxy resins.[citation needed]
Pet food additive
Vegetable oil is used in the production of some pet foods. AAFCO[22] defines vegetable oil in this context as the product of vegetable origin obtained by extracting the oil from seeds or fruits which are processed for edible purposes.[citation needed]
TheNNFCC estimates that the total net greenhouse gas savings when using vegetable oils in place of fossil fuel-based alternatives for fuel production, range from 18 to 100%.[24]
The production process of vegetable oil involves the removal of oil from plant components, typically seeds. This can be done via mechanical extraction using anoil mill or chemical extraction using a solvent. The extracted oil can then be purified and, if required, refined or chemically altered.[citation needed]
Mechanical extraction
Oils can be removed via mechanical extraction, termed "crushing" or "pressing". This method is typically used to produce the more traditional oils (e.g., olive, coconut, etc.), and it is preferred by mosthealth-food customers in the United States and in Europe.[citation needed] There are several different types of mechanical extraction.[25]Expeller pressing extraction is common, though thescrew press,ram press, and ghani (poweredmortar and pestle) are also used. Oilseed presses are commonly used in developing countries, among people for whom other extraction methods would be prohibitively expensive; the ghani is primarily used in India.[26] The amount of oil extracted using these methods varies widely, as shown in the following table for extractingmowrah butter in India:[27]
The processing of vegetable oil in commercial applications is commonly done by chemical extraction, using solvent extracts, which produces higher yields and is quicker and less expensive. The most common solvent is petroleum-derivedhexane. This technique is used for most of the "newer" industrial oils such as soybean and corn oils.[citation needed] After extraction, the solvent is evaporated out by heating the mixture to about 149 °C (300 °F).[29]
Unsaturated vegetable oils can be transformed through partial or completehydrogenation into oils of higher melting point, some of which, such asvegetable shortening, will remain solid at room temperature.
Hydrogenating vegetable oil is done by raising a blend of vegetable oil and a metal catalyst, typically nickel, in a near-vacuum to very high temperatures, and introducing hydrogen. This causes the carbon atoms of the oil to break double bonds with other carbons. Each carbon atom becomes single-bonded to an individual hydrogen atom, and the double bond between carbons can no longer exist. A fully hydrogenated oil, also called asaturated fat, has had all of its double bonds converted into single bonds. If apolyunsaturated oil is left incompletely hydrogenated (not all of the double bonds are reduced to single bonds), then it is a "partially hydrogenated oil" (PHO). An oil may be hydrogenated to increase resistance torancidity (oxidation) or to change its physical characteristics. As the degree of saturation is raised by full or partial hydrogenation, the oil's viscosity and melting point increase.
While full hydrogenation produces largely saturated fatty acids, partial hydrogenation results in the transformation of unsaturated cis fatty acids tounsaturated trans fatty acids in the oil mixture due to the heat used in hydrogenation. Partially hydrogenated oils and their trans fats have been linked to an increased risk of mortality fromcoronary heart disease,[31] among other increased health risks. These concerns have led to regulations mandating the removal of partially hydrogenated oils from food.[32]
Deodorization
In the processing of edible oils, the oil is heated under vacuum to near the smoke point or to about 232 °C (450 °F),[33] and water is introduced at the bottom of the oil. The water is immediately converted to steam, which bubbles through the oil, carrying with it any chemicals that are water-soluble. The steam sparging removes impurities that can impart unwanted flavors and odors to the oil. Deodorization is key to the manufacture of vegetable oils. Nearly all soybean, corn, and canola oils found on supermarket shelves go through a deodorization stage that removes trace amounts of odors and flavors, and lightens the color of the oil. However, the process commonly results in higher levels of trans fatty acids and distillation of the oil's natural compounds.[34][35][36]
World production of main vegetable oils by main producers
Typical productivity of some oil crops, measured intons (t) of oil produced perhectare (ha) of land per year (yr).Oil palm is by far the highest yielding crop, capable of producing about 4 tons of palm oil per hectare per year.
The following triglyceride vegetable oils account for almost all worldwide production, by volume. All are used as both cooking oils and asSVO or to make biodiesel. According to the USDA, the total world consumption of major vegetable oils in 2007/08 was:[41]
Used in cooking, cosmetics, soaps and as a fuel for traditional oil lamps
These figures include industrial and animal feed use. The majority of European rapeseed oil production is used to produce biodiesel, or used directly as fuel in diesel cars, which may require modification to heat the oil to reduce its higherviscosity.[citation needed]
Other significant oils include:
Corn oil, one of the most common cooking oils, is used for cooking oil, salad dressing, margarine, mayonnaise, prepared goods like spaghetti sauce and baking mixes, and to fry prepared foods like potato chips and French fries.
Seed oils are vegetable oils obtained from theseed (endosperm) rather than other parts of plants. Most vegetable oils are seed oils. Examples are sunflower, corn, and sesame oils.
Oils are extracted first by expeller or cold pressing methods, then solvent extraction removes the rest of the oils from the leftover matter. This is a method used by larger capacity oil mills. As the energy consumption of the mechanical press increases as more oil is released, it is more efficient to extract the rest of the oil (past around 60%) by solvent extraction.
A large quantity of used vegetable oil is produced and recycled, mainly from industrialdeep fryers in potato processing plants,snack food factories andfast food restaurants.
Recycled oil has numerous uses, including use as adirect fuel, as well as in the production ofbiodiesel,livestock feed, pet food, soap, detergent, cosmetics, and industrial chemicals.
Since 2002, an increasing number ofEuropean Union countries have prohibited the inclusion of recycled vegetable oil from catering in animal feed. Used cooking oils from food manufacturing, however, as well as fresh or unused cooking oil, continue to be used in their animal feed.[73]
Shelf life
Due to their susceptibility to oxidation from exposure to oxygen, heat and light, resulting in the formation ofoxidation products, such asperoxides andhydroperoxides, plant oils rich in polyunsaturated fatty acids have a limited shelf-life.[74][75]
Product labeling
In Canada, palm oil is one of five vegetable oils, along with palm kernel oil, coconut oil, peanut oil, and cocoa butter, which must be specifically named in the list of ingredients for a food product.[76] Also, oils in Canadian food products that have been modified or hydrogenated must contain the word "modified" or "hydrogenated" when listed as an ingredient.[77] A mix of oils other than the aforementioned exceptions may simply be listed as "vegetable oil" in Canada; however, if the food product is a cooking oil, salad oil or table oil, the type of oil must be specified and listing "vegetable oil" as an ingredient is not acceptable.[76]
From December 2014, all food products produced in theEuropean Union were legally required to indicate the specific vegetable oil used in their manufacture, following the introduction of the Food Information to Consumers Regulation.[78]
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^Robin Dand (1999).The International Cocoa Trade. Woodhead Publishing. p. 169.ISBN1-85573-434-6.
^abRuth Schuster (December 17, 2014). "8,000-year old olive oil found in Galilee, earliest known in world",Haaretz. Retrieved December 17, 2014.
^Ehud Galiliet al., "Evidence for Earliest Olive-Oil Production in Submerged Settlements off the Carmel Coast, Israel",Journal of Archaeological Science24:1141–1150 (1997)
^Bellis, Mary."The History of Soaps and Detergents".About.com. Archived fromthe original on July 14, 2012.In 1864, Caleb Johnson founded a soap company called B.J. Johnson Soap Co., in Milwaukee. In 1898, this company introduced a soap made of palm and olive oils called Palmolive.
^Commercial Agriculture, the Slave Trade and Slavery in Atlantic AfricaISBN978-1-847-01075-9 p. 22
^B.L. Axtell from research by R.M. Fairman (1992)."Illipe".Minor oil crops. FAO. Archived fromthe original on 2016-07-02. Retrieved2006-11-12.
^Aziz, KMA (2012)."Ghani". InIslam, Sirajul; Jamal, Ahmed A. (eds.).Banglapedia: National Encyclopedia of Bangladesh (Second ed.).Asiatic Society of Bangladesh.Archived from the original on 2016-05-09. Retrieved2016-05-08. A ghani is a traditional Indian oil press, driven by a horse or ox.
^Eisenmenger, Michael; Dunford, Nurhan T.; Eller, Fred; Taylor, Scott; Martinez, Jose (2006). "Pilot-scale supercritical carbon dioxide extraction and fractionation of wheat germ oil".Journal of the American Oil Chemists' Society.83 (10):863–868.doi:10.1007/s11746-006-5038-6.S2CID59940212.
^Trans Fat Task Force (June 2006)."TRANSforming the Food Supply (Appendix 9iii)". Archived fromthe original on February 25, 2007. Retrieved2007-01-09. (Consultation on the health implications of alternatives to trans fatty acids: Summary of Responses from Experts)
^Feuge, R. O."Vegetable Oils and Fats for Edible Use".usda.gov. Archived fromthe original on June 19, 2022. RetrievedMarch 13, 2019.Certain crude oils that contain minor amounts of impurities other than free fatty acids can be refined by a process known as steam refining. It is merely a high-temperature steam distillation under reduced pressure. The crude vegetable oil is heated to about 450°F. and maintained under a pressure of 0.25 inch of mercury or less while steam is passed through it. The steam strips the free fatty acids out of the oil. The process is used somewhat in Europe but not often in the United States.
^Lawrence Alan Johnson; Pamela J. White; Richard Galloway (2008).Soybeans : chemistry, production, processing, and utilization. Urbana, IL: AOCS Press.ISBN978-0-12-804352-3.OCLC491265615.
^abc"FoodData Central". United States Department of Agriculture. 1 April 2019. All values in this table are from this database unless otherwise cited or when italicized as the simple arithmetic sum of other component columns.
^abcdKatragadda, Harinageswara Rao; Fullana, Andrés; Sidhu, Sukh; Carbonell-Barrachina, Ángel A. (May 2010). "Emissions of volatile aldehydes from heated cooking oils".Food Chemistry.120 (1):59–65.doi:10.1016/j.foodchem.2009.09.070.
^"Canola oil, fat composition, 100 g". US National Nutrient Database, Release 28, United States Department of Agriculture. May 2016. Retrieved6 September 2017.
^"Coconut oil, fat composition, 100 g". US National Nutrient Database, Release 28, United States Department of Agriculture. May 2016. Retrieved6 September 2017.
^"Palm oil, fat composition, 100 g". US National Nutrient Database, Release 28, United States Department of Agriculture. May 2016. Retrieved6 September 2017.
^ab"Basic Labelling Requirements",Guide to Food Labelling and Advertising, Canadian Food Inspection Agency, 18 February 2014, archived fromthe original on 2015-04-06, retrieved2015-04-08
^"Common Name - Fats and Oils"(PDF),Labelling Requirements for Fats and Oils, Canadian Food Inspection Agency,archived(PDF) from the original on 2014-12-22, retrieved2015-04-08
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