oil
An oil is any nonpolar chemical substance
A chemical substance is a form of matter
In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can b ...
s extracted from seeds or from other parts of fruits. Like animal fat
Animal fats and oils are lipid
In biology
Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interactions, Phy ...
s, vegetable fats are ''mixtures'' of triglyceride
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s. Soybean oil
Soybean oil is a vegetable oil
Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butter are ex ...
, grape seed oil
Grape seed oil (also called grapeseed oil or grape oil) is a vegetable oil derived from the seeds
A seed is an Plant embryogenesis, embryonic plant enclosed in a testa (botany), protective outer covering. The formation of the seed is part of ...
, and cocoa butter
Cocoa butter, also called theobroma oil, is a pale-yellow, edible fat extracted from the cocoa bean
CoCoA (Computations in Commutative Algebra)
is a free computer algebra system developed by the University of Genova, Italy, used to compute ...
are examples of fats from seeds. Olive oil
Olive oil is a vegetable oil, liquid fat obtained from olives (the fruit of ''Olea europaea''; family Oleaceae), a traditional Tree fruit, tree crop of the Mediterranean Basin, produced by pressing whole olives and extracting the oil. It is com ...
, palm oil
Palm oil is an edible vegetable oil derived from the mesocarp (reddish pulp) of the fruit of the oil palms, primarily the African oil palm '' Elaeis guineensis'', and to a lesser extent from the American oil palm '' Elaeis oleifera'' and the ma ...
, and rice bran oil
Rice bran oil is the vegetable oil, oil extracted from the hard outer brown layer of rice called chaff (rice husk). It is known for its high smoke point of and mild flavor, making it suitable for high-temperature cooking methods such as stir fryin ...
are examples of fats from other parts of fruits. In common usage, vegetable ''oil'' may refer exclusively to vegetable fats which are liquid at room temperature. Vegetable oils are usually edible; non-edible oils derived mainly from petroleum are termed mineral oil
Mineral oil is any of various colorless, odorless, light mixtures of higher alkanes from a mineral
In geology
Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth ...
s. ''Vegetable oil'' sold in the U.S. is normally synonymous with ''soybean oil''.
Uses
In antiquity
Oils extracted from plants have been used since ancient times and in many cultures. Archaeological evidence shows that olives were turned into olive oil by 6000 BCE and 4500 BCE in present-dayIsrael
Israel (; he, יִשְׂרָאֵל, translit=Yīsrāʾēl; ar, إِسْرَائِيل, translit=ʾIsrāʾīl), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a ...
and Palestine
Palestine ( or ) most often refers to:
* State of Palestine, a ''de jure'' sovereign state in the Middle East
* Palestine (region), a geographical and historical region in the Middle East
Palestine may also refer to:
* Palestinian National Aut ...
.
In addition to use as food, fats and oils (both vegetable and mineral) have long been used as fuel, typically in lamps
Lamp, lamps or LAMP may refer to:
Lighting
* Lamp, a fuel burning illumination
** Oil lamp
An oil lamp is an object used to produce light continuously for a period of time using an oil-based fuel source. The use of oil lamps began thousands ...
which were a principal source of illumination in ancient times. Oils may have been used for lubrication, but there is no evidence for this. Vegetable oils were probably more valuable as food and lamp-oil; Babylon
''Bābili(m)''
* sux, 𒆍𒀭𒊏𒆠
* arc, 𐡁𐡁𐡋 ''Babil''
* grc-gre, Βαβυλών ''Babylṓn''
* he, בָּבֶל ''Bavel''
* peo, 𐎲𐎠𐎲𐎡𐎽𐎢 ''Bābiru''
* elx, 𒀸𒁀𒉿𒇷 ''Babili''
* Kassite: ''Karanduniash''
...
ian mineral oil was known to be used as fuel, but there are no references to lubrication. Pliny the Elder#REDIRECT Pliny the Elder
Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman author, a naturalist
Natural history is a domain of inquiry involving organisms, including animals, fungus, fungi, and plants, in their natu ...
reported that animal-derived fats such as lard were used to lubricate the axles of carts.
Culinary
Many vegetable oils are consumed directly, or indirectly as ingredients in food – a role that they share with someanimal fats
Animal fats and oils are lipid
In biology
Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interactions, Phy ...
, including butter
Butter is a dairy product
Dairy products or milk products are a type of food
Food is any substance consumed to provide nutritional support for an organism
In biology, an organism (from Ancient Greek, Greek: ὀργανισμός ...
, ghee
Ghee (Sanskrit: Ghṛta) is a class of clarified butter that originated in ancient India. It is commonly used in cuisine of the Indian subcontinent, Middle Eastern cuisine, traditional medicine, and religious rituals.
Ghee is made of butter, b ...
, lard
Lard is a semi-solid white fat product obtained by rendering the fatty tissue of a pig.Lard
entry in the ...
, and entry in the ...
schmaltz
Schmaltz (also spelled schmalz or shmalz) is rendered (clarified) chicken
The chicken (''Gallus gallus domesticus''), a subspecies of the red junglefowl, is a type of domestication, domesticated fowl, originally from Asia. Rooster or c ...
. The oils serve a number of purposes in this role:
* Shortening
, a type of shortening common in Italy and Corsican cuisine, Corsica (where it is named ''sdruttu'')
Shortening is any fat that is a solid at room temperature and used to make shortcrust pastry, crumbly pastry and other food products. Although butt ...
– as in giving pastries a crumbly texture.
* Enriching - adding calories and satisfaction in consumption
* Texture – altering how ingredients combine, especially fats and starches
* Flavoring – examples include olive
The olive, known by the botanical name ''Olea europaea'', meaning "European olive", is a species
In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit o ...
, sesame
Sesame ( or ; ''Sesamum indicum'') is a flowering plant
The flowering plants, also known as Angiospermae (), or Magnoliophyta (), are the most diverse group of Embryophyte, land plants, with 64 Order(biology), orders, 416 Family (biology), fa ...
, or almond
The almond (''Prunus dulcis'', syn. ''Prunus amygdalus'') is a species of tree native to Iran
Iran ( fa, ایران ), also called Persia and officially the Islamic Republic of Iran ( fa, جمهوری اسلامی ایران ), is a ...
oil
* Flavor base – oils can also "carry" flavors of other ingredients, such as peppers, 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, , and used to fry foods. Oils for this purpose must have a high flash point
The flash point of a volatile material is the lowest temperature
Temperature is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy, present in all matter, which is the source of the occurrence of he ...
. Such oils include both the major cooking oils – soybean
The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses.
Traditional unfermented food uses of soybeans include soy milk, from which tofu and t ...
, rapeseed
Rapeseed (''Brassica napus ''subsp.'' napus''), also known as rape, or oilseed rape, is a bright-yellow flowering member of the family Brassicaceae (mustard or cabbage family), cultivated mainly for its oil-rich seed, which naturally contains ...
, canola
Canola oil is a vegetable oil derived from a variety of rapeseed that is low in erucic acid, as opposed to colza oil. There are both Edible oil, edible and industrial forms produced from the seed of any of several cultivars of the plant family ...
, sunflower
''Helianthus'' () is a genus
Genus (plural genera) is a taxonomic rank
Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such classification. The term may also re ...
, safflower
Safflower, ''Carthamus tinctorius'', is a highly branched, herbaceous, thistle-like annual plant
240px, Peas are an annual plant.
An annual plant is a plant that completes its biological life cycle, life cycle, from germination to the produ ...
, peanut
The peanut, also known as the groundnut, goober (US), pindar (US) or monkey nut (UK), and taxonomically classified as ''Arachis hypogaea'', is a legume
A legume () is a plant
Plants are mainly multicellular organisms, predominantly ...
, cottonseed
Cottonseed is the seed of the cotton plant.
Composition
The mature seeds are brown ovoids weighing about a tenth of a gram. By weight, they are 60% cotyledon, 32% coat and 8% embryonic root and shoot. These are 20% protein, 20% oil and 3.5% sta ...
, etc. – and tropical oils, such as coconut
The coconut tree (''Cocos nucifera'') is a member of the palm tree family
In human society, family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other rela ...
, palm
Palm most commonly refers to:
* Palm of the hand, the central region of the front of the hand and a subdivision of the cubit
* Palm trees, of family Arecaceae
**List of Arecaceae genera
* Several Arecaceae#Other plants, other plants known as Palm
P ...
, and rice bran
Image:Wheat-kernel nutrition.png, 300px, Wheat kernel compartments and macronutrients
Bran, also known as miller's bran, is the hard outer layers of Cereal, cereal grain. It consists of the combined aleurone and pericarp. Along with cereal germ ...
. The latter are particularly valued in Asian cultures for high-temperature cooking, because of their unusually high flash points.
Hydrogenated oils
Unsaturated vegetable oils can be transformed through partial or complete "hydrogenation
Hydrogenation is a chemical reaction
A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical
A chemical substance is a form of matter having constant ...
" into oils of higher melting point, some of which, such as vegetable shortening
, a type of shortening common in Italy
Italy ( it, Italia ), officially the Italian Republic ( it, Repubblica Italiana, links=no ), is a country consisting of a Northern Italy, continental part, delimited by the Alps, a Italian Peninsula, pen ...
, will remain solid at room temperature.
The hydrogenation process involves " sparging" the oil at high temperature and pressure with hydrogen
Hydrogen is the chemical element
Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements
In chemistry, an element is a pure substance consisting only of atoms that all have the same ...
in the presence of a catalyst
that utilizes a low-temperature oxidation catalyst to convert carbon monoxide to less toxic carbon dioxide at room temperature. It can also remove formaldehyde from the air.
Catalysis () is the process of increasing the reaction rate, rate of a ...
, typically a powdered nickel
Nickel is a chemical element
Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements
In chemistry, an element is a pure substance consisting only of atoms that all have the same numb ...
compound, such as Raney nickel
Raney nickel , also called spongy nickel, is a fine-grained solid composed mostly of nickel derived from a nickel–aluminium
Aluminium (aluminum in American English, American and Canadian English) is a chemical element with the Symbol ( ...
. Chemically, hydrogenation is the reduction of a carbon-carbon double bond to a single bond, by addition of hydrogen atoms. Since the surface of the metal catalyst is covered with hydrogen atoms, when the double bonds of the unsaturated oil come into contact with the catalyst, it reacts with the hydrogen atoms, forming new bonds with the two carbon atoms; each carbon atom becomes single-bonded to an individual hydrogen atom, and the double bond between carbons can no longer exist. In organic chemistry
Organic chemistry is a branch of chemistry that studies the structure, properties and reactions of organic compounds, which contain carbon in covalent bonding.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry''. Oxford University ...
, unsaturation is considered as a pair of hydrogen atoms missing from the (hypothetical) fully-saturated carbon chain. The level to which an organic molecule is deficient in hydrogen, is called the degree of unsaturation (DoU); as the degree of unsaturation decreases, the oil progresses toward being fully hydrogenated (when DoU = 0). A fully hydrogenated oil, also called a saturated fat
A saturated fat is a type of fat in which the fatty acid chains have all or predominantly single bonds. A fat is made of two kinds of smaller molecules: glycerol and fatty acids. Fats are made of long chains of carbon (C) atoms. Some carbon a ...
, has had all of its double bonds converted into single bonds. If a polyunsaturated
In nutrition
Nutrition is the biochemical and physiological process by which an organism
In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguous system that embodies ...
oil is left incompletely-hydrogenated (not all of the double bonds are reduced to single bonds), then it is a "partially hydrogenated oil" (PHO). PHOs are the primary dietary source of artificial trans fat in processed foods. An oil may be hydrogenated to increase resistance to rancidity (oxidation
(mild reducing agent) are added to powdered potassium permanganate
Potassium permanganate is an inorganic compound with the chemical formula KMnO4 and composed of potassium ion, K+ and permanganate, . It is a purplish-black crystalline salt, ...
) or to change its physical characteristics. As the degree of unsaturation is lowered by full or partial hydrogenation, the oil's viscosity and melting point increase.
The use of hydrogenated oils in foods has never been completely satisfactory. Because the center arm of the triglyceride
300px, Example of an unsaturated fat triglyceride (C55H98O6). Left part: glycerol; right part, from top to bottom: palmitic acid, oleic acid">palmitic_acid.html" ;"title="glycerol; right part, from top to bottom: palmitic acid">glycerol; right par ...
is shielded somewhat by the end fatty acids, most of the hydrogenation occurs on the end fatty acids, thus making the resulting fat more brittle. A margarine made from naturally more saturated oils will be more plastic (more "spreadable") than a margarine made from hydrogenated soy oil. While ''full hydrogenation'' produces largely saturated fatty acids, partial hydrogenation results in the transformation of unsaturated cis fatty acids to unsaturated 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 from coronary heart disease
Coronary artery disease (CAD), also called coronary heart disease (CHD), Ischemia, ischemic heart disease (IHD), or simply heart disease, involves the reduction of blood flow to the myocardium, heart muscle due to build-up of plaque (atherosclero ...
, (Consultation on the health implications of alternatives to trans fatty acids: Summary of Responses from Experts) among other increased health risks.
In the US, the Standard of Identity for a product labeled as "vegetable oil margarine" specifies only canola, safflower, sunflower, corn, soybean, or peanut oil may be used. Products not labeled "vegetable oil margarine" do not have that restriction.
Industrial
Vegetable oils are used as an ingredient or component in many manufactured products. 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 oil
A drying oil is an oil that hardens to a tough, solid film after a period of exposure to air, at room temperature. The oil hardens through a chemical reaction in which the components cross-link, crosslink (and hence, polymerize) by the action of ox ...
s, and are used in making paints and other wood treatment products. They are used in alkydAn alkyd is a polyester
Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Poly ...
resin production. Dammar oil (a mixture of linseed oil and dammar
Dammar resin
Dammar, also called dammar gum, or damar gum, is a resin
In polymer chemistry and materials science
The interdisciplinary field of materials science, also commonly termed materials science and engineering, covers the design ...
resin), for example, is used almost exclusively in treating the hulls of wooden boats. Vegetable oils are increasingly being used in the electrical industry as insulator
Insulator may refer to:
* Insulator (electricity), a substance that resists electricity
** Pin insulator, a device that isolates a wire from a physical support such as a pin on a utility pole
** Strain insulator, a device that is designed to work i ...
s as vegetable oils are not toxic to the environment, biodegradable
Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi.
Mechanisms
The process of biodegradation can be divided into three stages: biodeterioration, biofragmentation, and assimilation (biology), assimila ...
if spilled and have high flash
FLASH, acronym of ''Free Electron LASer in Hamburg'', a particle accelerator
, a synchrotron collider type particle accelerator at Fermi National Accelerator Laboratory (Fermilab), Batavia, Illinois, USA. Shut down in 2011, until 2007 it was the ...
and fire points. However, vegetable oils are less stable chemically, so they are generally used in systems where they are not exposed to oxygen
Oxygen is the chemical element with the chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen Group (periodic table), group in the periodic table, a highly Chemical reaction, reactive nonmetal, and an oxidizing a ...
, 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 by Fischer esterification
Fischer is an Alsatian surname, derived from the profession of the fisherman. The name Fischer is the fourth most common German surname. The English version is Fisher.
People with the surname A
* Abraham Fischer
Abraham Fischer (4 September ...
. Tetraesters generally have high stability to oxidation and have found use as engine lubricants. Vegetable oil is being used to produce biodegradable hydraulic fluid
A hydraulic fluid or hydraulic liquid is the medium by which power is transferred in hydraulic machinery
Hydraulic machines use liquid
A liquid is a nearly incompressible fluid
In physics, a fluid is a substance that continually Def ...
and lubricant
A lubricant is a substance that helps to reduce friction
Friction is the force
In physics
Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is th ...
.
One limiting factor in industrial uses of vegetable oils is that all such oils are susceptible to becoming rancid. Oils that are more stable, such as ben oil
Ben oil is pressed from the seeds of the '' Moringa oleifera'', known variously as the horseradish tree, ben oil tree, or drumstick tree. The oil is characterized by an unusually long shelf life and a mild, but pleasant taste. The name of the oil i ...
or mineral oil
Mineral oil is any of various colorless, odorless, light mixtures of higher alkanes from a mineral
In geology
Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth ...
, are thus preferred for industrial uses. Castor oil
Castor oil is a vegetable oil pressed from castor beans.
Castor oil is a colourless to very pale yellow liquid with a distinct taste and odor. Its boiling point is and its density is 0.961 g/cm3. It includes a mixture of triglycerides i ...
has numerous industrial uses, owing to the presence of hydroxyl
A hydroxy or hydroxyl group is a functional group with the chemical formula -OH and composed of one oxygen
Oxygen is the chemical element with the chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen Group ...
group on the fatty acid. Castor oil is a precursor to Nylon 11.Castor oil may also be reacted with epichlorohydrin
Epichlorohydrin (abbreviated ECH) is an organochlorine compound and an epoxide. Despite its name, it is not a halohydrin. It is a colorless liquid with a pungent, garlic-like odor, moderately soluble in water, but miscible
Miscibility () is th ...
to make a glycidyl ether which is used as a diluent and flexibilizer with epoxy
Epoxy refers to any of the basic components or Curing (chemistry), cured end products of epoxy resins, as well as a colloquial name for the epoxide functional group. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers a ...
resins.
Pet food additive
Vegetable oil is used in the production of some pet foods. AAFCO 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.Fuel
Vegetable oils are also used to makebiodiesel
Biodiesel is a form of diesel fuel
Diesel fuel in general is any liquid fuel specifically designed for use in diesel engine
The diesel engine, named after Rudolf Diesel, is an internal combustion engine
An internal combustion e ...
, which can be used like conventional diesel. Some vegetable oil blends are used in unmodified vehicles but straight vegetable oilImage:Used vegetable cooking oil.png, frame, Waste vegetable oil which has been filtered.
Vegetable oil can be used as an alternative fuel in diesel engines and in heating oil burners. When vegetable oil is used directly as a fuel, in either modifie ...
, also known as pure plant oil, needs specially prepared vehicles which have a method of heating the oil to reduce its viscosity
The viscosity of a fluid is a measure of its drag (physics), resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity can be ...
. The use of vegetable oils as alternative energy is growing and the availability of biodiesel around the world is increasing.
The NNFCC
NNFCC is a consultancy company specialising in bioenergy, biofuels and bio-based products.
History
Established by the UK Government
The Government of the United Kingdom, domestically referred to as Her Majesty's Government, is the cent ...
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%.
Production
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
An oil mill is a grinding mill designed to crush or bruise oil-bearing seeds, such as linseed
Flax, also known as common flax or linseed, is a flowering plant
The flowering plants, also known as Angiospermae (), or Magnoliophyta (), are the m ...
or chemical extraction using a solvent. The extracted oil can then be purified and, if required, refined or chemically altered.
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 most " health-food" customers in the United States and in Europe. There are several different types of mechanical extraction. -pressing extraction is common, though the
screw press
A screw press is a type of machine press in which the ram is driven up and down by a screw. The screw shaft can be driven by a handle or a wheel. It works by using a coarse screw to convert the rotation of the handle or drive-wheel into a small ...
, ram press
A RAM press (or ram press) is a machine, invented in the United States of America, USA in the mid-1940s, that is used to press clay into moulding (process), moulded shapes, such as plates and bowls. In operation a slice of de-aired clay body is pl ...
, and ghani (powered mortar and pestle
Mortar and pestle is a set of 2 simple tools used since the stone age up to the present day to prepare ingredients or substances by crushing and grinding them into a fine paste or powder in the kitchen, laboratory, and pharmacy. The ''morta ...
) 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. The amount of oil extracted using these methods varies widely, as shown in the following table for extracting mowrah butter in India:
Solvent extraction
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
Hexane () is an organic compound, a straight-chain alkane with six carbon atoms and has the molecular formula C6H14.
Hexane is a significant constituent of gasoline. It is a colorless liquid, odorless when pure, and with boiling points approxim ...
. This technique is used for most of the "newer" industrial oils such as soybean and corn oils. After extraction, the solvent is evaporated out by heating the mixture to about .
Supercritical carbon dioxide
upright=1.3, Carbon dioxide pressure-temperature phase diagram
Supercritical carbon dioxide (s) is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure.
Carbon dioxide usually behaves as a ...
can be used as a non-toxic alternative to other solvents.
Hydrogenation
Oils may be partiallyhydrogenated
Hydrogenation is a chemical reaction
A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical
A chemical substance is a form of matter having constant ...
to produce various ingredient oils. Lightly hydrogenated oils have very similar physical characteristics to regular soy oil, but are more resistant to becoming rancid. Margarine oils need to be mostly solid at 32 °C (90 °F) so that the margarine does not melt in warm rooms, yet it needs to be completely liquid at 37 °C (98 °F), so that it doesn't leave a "lardy" taste in the mouth.
Hardening vegetable oil is done by raising a blend of vegetable oil and a catalyst in 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 forming a new single-bond with a hydrogen atom. Adding these hydrogen atoms to the oil makes it more solid, raises the smoke point
The smoke point, also referred to as the burning point, is the temperature at which an oil or fat begins to produce a continuous bluish smoke that becomes clearly visible, dependent upon specific and defined conditions. Smoke point values can vary ...
, and makes the oil more stable.
Hydrogenated vegetable oils differ in two major ways from other oils which are equally saturated. During hydrogenation, it is easier for hydrogen to come into contact with the fatty acids on the end of the triglyceride, and less easy for them to come into contact with the center fatty acid. This makes the resulting fat more brittle than a tropical oil; soy margarines are less "spreadable". The other difference is that trans fatty acids (often called trans fat
Trans fat, also called trans-unsaturated fatty acids or trans fatty acids, is a type of unsaturated fat that naturally occurs in small amounts in meat and milk fat. It became widely produced as an unintentional byproduct in the industrial processin ...
) are formed in the hydrogenation reactor, and may amount to as much as 40 percent by weight of a partially hydrogenated oil. Hydrogenated oils, especially partially hydrogenated oils with their higher amounts of trans fatty acids, are increasingly thought to be unhealthy.
Deodorization
In the processing of edible oils, the oil is heated under vacuum to near the smoke point or to about , and water is introduced at the bottom of the oil. The water immediately is converted to steam, which bubbles through the oil, carrying with it any chemicals which 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.Occupational exposure
People can breathe in vegetable oil mist in the workplace. The U.S.Occupational Safety and Health Administration
The Occupational Safety and Health Administration (OSHA ) is a large regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. Congress established the agency ...
(OSHA) has set the legal limit (permissible exposure limitThe permissible exposure limit (PEL or OSHA PEL) is a legal limit in the United States
The United States of America (USA), commonly known as the United States (U.S. or US), or America, is a country Contiguous United States, primarily located ...
) for vegetable oil mist exposure in the workplace as 15 mg/m3 total exposure and 5 mg/m3 respiratory exposure over an 8-hour workday. The U.S. National Institute for Occupational Safety and Health
The National Institute for Occupational Safety and Health (NIOSH, ) is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury
Injury, also known as physical ...
(NIOSH) has set a recommended exposure limit
A recommended exposure limit (REL) is an occupational exposure limit that has been recommended by the United States
The United States of America (USA), commonly known as the United States (U.S. or US), or America, is a country Contiguous Un ...
(REL) of 10 mg/m3 total exposure and 5 mg/m3 respiratory exposure over an 8-hour workday.
Yield
Typical productivity of some oil crops, measured inton
The ton is a unit of measure. It has a long history and has acquired a number of meanings and uses over the years. It is used principally as a unit of mass. Its original use as a measurement of volume has continued in the capacity of cargo ships ...
s (t) of oil produced per hectare
The hectare (; SI symbol: ha) is a non-SI metric unit of area
Area is the quantity that expresses the extent of a two-dimensional region, shape, or planar lamina, in the plane. Surface area is its analog on the two-dimensional surface ...
(ha) of land per year (yr). Oil palm
''Elaeis'' () is a genus of palms containing two species, called oil palms. They are used in commercial agriculture
Agriculture is the science, art and practice of cultivating plants and livestock. Agriculture was the key development in ...
is by far the highest yielding crop, capable of producing about 4 tons of palm oil per hectare per year.
Particular oils
The following triglyceride vegetable oils account for almost all worldwide production, by volume. All are used as both cooking oils and as SVO or to make biodiesel. According to the USDA, the total world consumption of major vegetable oils in 2007/08 was:, Table 03: Major Vegetable Oils: World Supply and Distribution aOilseeds: World Markets and Trade Monthly Circular
Note that 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 higher
viscosity
The viscosity of a fluid is a measure of its drag (physics), resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity can be ...
.
Other significant triglyceride oils include:
* Corn oil#REDIRECT corn oil
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 ...
, one of the most common cooking oils. As of 2006, the US produced about 1.09 million metric tons Corn Refiners AssociationCorn Oil
5th Edition. 2006 of corn oil, which 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. *
Grape seed oil
Grape seed oil (also called grapeseed oil or grape oil) is a vegetable oil derived from the seeds
A seed is an Plant embryogenesis, embryonic plant enclosed in a testa (botany), protective outer covering. The formation of the seed is part of ...
, used in cooking and cosmetics
* Hazelnut oil
The hazelnut is the nut (fruit), fruit of the hazel and therefore includes any of the nuts deriving from species of the genus ''Corylus'', especially the nuts of the species ''Corylus avellana''. They are also known as cobnuts or filberts ac ...
and other nut oils
* Linseed oil
Linseed oil, also known as flaxseed oil or flax oil (in its edible form), is a colourless to yellowish oil obtained from the dried, ripened seeds of the flax plant (''Linum usitatissimum''). The oil is obtained by Expeller pressing, pressing, somet ...
, from flax
Flax, also known as common flax or linseed, is a flowering plant
The flowering plants, also known as Angiospermae (), or Magnoliophyta (), are the most diverse group of Embryophyte, land plants, with 64 Order(biology), orders, 416 Family (biol ...
seeds
* Rice bran oil
Rice bran oil is the vegetable oil, oil extracted from the hard outer brown layer of rice called chaff (rice husk). It is known for its high smoke point of and mild flavor, making it suitable for high-temperature cooking methods such as stir fryin ...
, from rice grains
* Safflower oil
Safflower, ''Carthamus tinctorius'', is a highly branched, herbaceous, thistle-like annual plant in the sunflower family Asteraceae. It is commercially cultivated for vegetable oil extracted from the seeds and was used by the early Spanish colon ...
, a flavorless and colorless cooking oil
* Sesame oil
Sesame oil is an edible vegetable oil
Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butte ...
, used as a cooking oil, and as a massage oil, particularly in India
* Açaí palm
The açaí palm (, , from Nheengatu ''asai''), ''Euterpe
Euterpe (; el, Εὐτέρπη, lit=rejoicing well' or 'delight , from grc, εὖ, eû, well + el, τέρπειν, térpein, to please) was one of the Muses
In ancient Greek religio ...
oil, used in culinary and cosmetics
* Jambú oil, is extracted from the flowers, leaves and stem from jambu (''Acmella oleracea''), contains spilanthol
* Graviola oil, derived from ''Annona muricata''
* Tucumã oil, from ''Astrocaryum aculeatum'' is used to manufacture soap.
* Brazil nut oil, culinary and cosmetics use
* Carapa oil, pharmaceutical use and anti-mosquito candle
* Buriti oil, from ''Mauritia flexuosa'', used in cosmetics (skin and hair care)
* Passion fruit oil, derived from ''Passiflora edulis'', has varied applications in cosmetics manufacturing and for uses as a human or animal food.
* Pracaxi oil, obtained from ''Pentaclethra macroloba'', cosmetics use
* Solarium oil, derived from chloroplasts, various applications in cooking
Composition of fats
History
Such oils have been part of human culture for millennia.Ruth Schuster (December 17, 2014). "8,000-year old olive oil found in Galilee, earliest known in world", ''Haaretz''. Retrieved December 17, 2014. Oils such as poppy seed, rapeseed, linseed, almond oil, sesame seed, safflower, and cottonseed were variously used since at least the Bronze Age in the Middle East, Africa and Central Asia. Vegetable oils have been used for lighting fuel, cooking, medicine and lubrication. The Chinese started to use vegetable oil for stir-frying instead of animal fats during the Song dynasty (960–1279) 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 and it became highly sought-after commodity by British traders for use as an industrial lubricant for machinery during Britain's Industrial Revolution. Palm oil formed the basis of soap products, such as Lever Brothers' (now Unilever) "Sunlight" soap, and the American Palmolive brand., and by around 1870, palm oil constituted the primary export of some West African countries. In 1780 Carl Wilhelm Scheele demonstrated that fats were derived from glycerol. Thirty years later Michel Eugène Chevreul deduced that these fats were esters of fatty acids and glycerol. Wilhelm Normann, a German chemist introduced thehydrogenation
Hydrogenation is a chemical reaction
A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical
A chemical substance is a form of matter having constant ...
of liquid fats in 1901, creating what later became known as trans fat
Trans fat, also called trans-unsaturated fatty acids or trans fatty acids, is a type of unsaturated fat that naturally occurs in small amounts in meat and milk fat. It became widely produced as an unintentional byproduct in the industrial processin ...
s, leading to the development of the global production of margarine and vegetable shortening
, a type of shortening common in Italy
Italy ( it, Italia ), officially the Italian Republic ( it, Repubblica Italiana, links=no ), is a country consisting of a Northern Italy, continental part, delimited by the Alps, a Italian Peninsula, pen ...
.
In the USA cottonseed oil was developed, and marketed by Procter & Gamble as a creamed shortening – Crisco – as early as 1911. Ginning mills were happy to have someone haul away the cotton seeds. The extracted oil was refined and partially Hydrogenation, hydrogenated 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.
Soybean oil
Soybean oil is a vegetable oil
Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butter are ex ...
has been used in China since before historical records. It arrived in the US in the 1930s. 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. Roger Drackett had a successful new product with Windex, but he invested heavily in soybean research, seeing it as a smart investment. By the 1950s and 1960s, soybean oil had become the most popular vegetable oil in the US; today it is second only to palm oil
Palm oil is an edible vegetable oil derived from the mesocarp (reddish pulp) of the fruit of the oil palms, primarily the African oil palm '' Elaeis guineensis'', and to a lesser extent from the American oil palm '' Elaeis oleifera'' and the ma ...
. In 2018–2019, world production was at 57.4 MT with the leading producers including China (16.6 MT), US (10.9 MT), Argentina (8.4 MT), Brazil (8.2 MT), and EU (3.2 MT).
The early 20th century also saw the start of the use of Vegetable oil fuel, vegetable oil as a fuel in diesel 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 having a source of fuel readily available. Diesel's first engine ran on its own power for the first time in Augsburg, Germany, on 10 August 1893 on nothing but peanut oil. In remembrance of this event, 10 August has been declaredInternational Biodiesel Day
. The first patent on Biodiesel was granted in 1937. 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
Biodiesel is a form of diesel fuel
Diesel fuel in general is any liquid fuel specifically designed for use in diesel engine
The diesel engine, named after Rudolf Diesel, is an internal combustion engine
An internal combustion e ...
, produced from oils or fats using transesterification is more widely used. It is Led by Brazil, many countries built biodiesel production, biodiesel plants during the 1990s, and it is now widely available for use in motor vehicles, and is the most common biofuel in Europe today. In France, biodiesel is incorporated at a rate of 8% in the fuel used by all French diesel vehicles.
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, 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.
Used oil
A large quantity of used vegetable oil is produced and recycled, mainly from industrial deep fryers in potato processing plants, snack food factories and fast food restaurants. Recycled oil has numerous uses, including use as a Vegetable oil fuel, direct fuel, as well as in the production ofbiodiesel
Biodiesel is a form of diesel fuel
Diesel fuel in general is any liquid fuel specifically designed for use in diesel engine
The diesel engine, named after Rudolf Diesel, is an internal combustion engine
An internal combustion e ...
, soap, compound feed, animal feed, pet food, detergent, and cosmetics. It is traded as the commodity, yellow grease.
Since 2002, an increasing number of European 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 animal feed.
Shelf life
Due to their susceptibility to oxidation from the exposure to oxygen, heat and light, resulting in the formation of redox, oxidation products, such as peroxides and hydroperoxides, plant oils rich in polyunsaturated fatty acids have a limited shelf-life.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. Also, oils in Canadian food products which have been modified or hydrogenated must contain the word "modified" or "hydrogenated" when listed as an ingredient. 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. From December 2014, all food products produced in the European Union were legally required to indicate the specific vegetable oil used in their manufacture, following the introduction of the Food Information to Consumers Regulation.See also
* Algae culture * Cholesterol * Decorticator * Deodorizer * Essential oils * Fatty acid * Food extrusion * Fragrance oil * Lipid * List of macerated oils * List of vegetable oils * Neem * Non-food crops * Oleochemistry * Soap * Vernonia oil * Vegetable oil recyclingNotes and references
Further reading
* * * {{DEFAULTSORT:Vegetable oil Vegetable oils, Plant products