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Vegetable oils are triglycerides extracted from plants. Some of these oils have been part of human culture for millennia. [1] Edible vegetable oils are used in food, both in cooking and as supplements. Many oils, edible and otherwise, are burned as fuel, such as in oil lamps and as a substitute for petroleum-based fuels. Some of the many other uses include wood finishing, oil painting, and skin care.
The term "vegetable oil" can be narrowly defined as referring only to substances that are liquid at room temperature, [2] or broadly defined without regard to a substance's state (liquid or solid) at a given temperature. [3] While a large majority of the entries in this list fit the narrower of these definitions, some do not qualify as vegetable oils according to all understandings of the term.
Vegetable oils can be classified in several ways. For instance, by their use or by the method used to extract them. In this article, vegetable oils are grouped in common classes of use.
There are several types of plant oils, distinguished by the method used to extract the oil from the plant. The relevant part of the plant may be placed under pressure to extract the oil, giving an expressed (or pressed) oil. The oils included in this list are of this type. Oils may also be extracted from plants by dissolving parts of plants in water or another solvent. The solution may be separated from the plant material and concentrated, giving an extracted or leached oil. The mixture may also be separated by distilling the oil away from the plant material. Oils extracted by this latter method are called essential oils. Essential oils often have different properties and uses than pressed or leached vegetable oils. Finally, macerated oils are made by infusing parts of plants in a base oil, a process called liquid–liquid extraction.
Most, but not all vegetable oils are extracted from the fruits or seeds of plants. For instance, palm oil is extracted from palm fruits, while soybean oil is extracted from soybean seeds. Vegetable oils may also be classified by grouping oils extracted from similar plants, such as "nut oils".
Although most plants contain some oil, only the oil from certain major oil crops [4] complemented by a few dozen minor oil crops [5] is widely used and traded.
Oils from plants are used for several different purposes. Edible vegetable oils may be used for cooking, or as food additives. Many vegetable oils, edible and otherwise, are burned as fuel, for instance as a substitute for petroleum-based fuels. Some may be also used for cosmetics, medical purposes, wood finishing, oil painting and other industrial purposes.
These oils make up a significant fraction of worldwide edible oil production. All are also used as fuel oils.
Nut oils are generally used in cooking, for their flavor. Most are quite costly, because of the difficulty of extracting the oil.
A number of citrus plants yield pressed oils. Some, such as lemon and orange oil, are used as essential oils, which is uncommon for pressed oils. [note 1] [35] The seeds of many if not most members of the citrus family yield usable oils. [35] [36] [37] [38]
Members of the Cucurbitaceae include gourds, melons, pumpkins, and squashes. Seeds from these plants are noted for their oil content, but little information is available on methods of extracting the oil. In most cases, the plants are grown as food, with dietary use of the oils as a byproduct of using the seeds as food. [45]
A number of oils are used as food supplements (or "nutraceuticals"), for their nutrient content or purported medicinal effect. Borage seed oil, blackcurrant seed oil, and evening primrose oil all have a significant amount of gamma-Linolenic acid (GLA) (about 23%, 15–20% and 7–10%, respectively), and it is this that has drawn the interest of researchers.
A number of oils are used for biofuel (biodiesel and Straight Vegetable Oil) in addition to having other uses. Other oils are used only as biofuel. [note 4] [147]
Although diesel engines were invented, in part, with vegetable oil in mind, [148] diesel fuel is almost exclusively petroleum-based. Vegetable oils are evaluated for use as a biofuel based on:
The oils listed immediately below are all (primarily) used for other purposes – all but tung oil are edible – but have been considered for use as biofuel.
These oils are extracted from plants that are cultivated solely for producing oil-based biofuel. [note 5] These, plus the major oils described above, have received much more attention as fuel oils than other plant oils.
Drying oils are vegetable oils that dry to a hard finish at normal room temperature. Such oils are used as the basis of oil paints, and in other paint and wood finishing applications. In addition to the oils listed here, walnut, sunflower and safflower oil are also considered to be drying oils. [176]
A number of pressed vegetable oils are either not edible, or not used as an edible oil.
Palm oil is an edible vegetable oil derived from the mesocarp of the fruit of oil palms. The oil is used in food manufacturing, in beauty products, and as biofuel. Palm oil accounted for about 36% of global oils produced from oil crops in 2014. Palm oils are easier to stabilize and maintain quality of flavor and consistency in ultra-processed foods, so are frequently favored by food manufacturers. On average globally, humans consumed 7.7 kg (17 lb) of palm oil per person in 2015. Demand has also increased for other uses, such as cosmetics and biofuels, creating more demand on the supply encouraging the growth of palm oil plantations in tropical countries.
Biodiesel is a renewable biofuel, a form of diesel fuel, derived from biological sources like vegetable oils, animal fats, or recycled greases, and consisting of long-chain fatty acid esters. It is typically made from fats.
Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of edible plants. Like animal fats, vegetable fats are mixtures of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or fats from seeds. Olive oil, palm oil, and rice bran oil are examples of fats from other parts of plants. In common usage, vegetable oil may refer exclusively to vegetable fats which are liquid at room temperature. Vegetable oils are usually edible.
Coconut oil is an edible oil derived from the kernels, meat, and milk of the coconut palm fruit. Coconut oil is a white solid fat below around 25 °C (77 °F), and a clear thin liquid oil in warmer climates. Unrefined varieties have a distinct coconut aroma. Coconut oil is used as a food oil, and in industrial applications for cosmetics and detergent production. The oil is rich in medium-chain fatty acids.
Hemp oil is oil obtained by pressing hemp seeds. Cold pressed, unrefined hemp oil is dark to clear light green in color, with a nutty flavor. The darker the color, the grassier the flavour. It should not be confused with hash oil, a tetrahydrocannabinol-containing oil made from the Cannabis flower.
Grape seed oil is a vegetable oil derived from the seeds of grapes. A by-product of the winemaking industry, it is typically used for edible applications.
Cottonseed oil is cooking oil from the seeds of cotton plants of various species, mainly Gossypium hirsutum and Gossypium herbaceum, that are grown for cotton fiber, animal feed, and oil.
Biodiesel production is the process of producing the biofuel, biodiesel, through the chemical reactions of transesterification and esterification. This process renders a product (chemistry) and by-products.
Sesame oil is an edible vegetable oil derived from sesame seeds. The oil is one of the earliest-known crop-based oils. Worldwide mass modern production is limited due to the inefficient manual harvesting process required to extract the oil. Oil made from raw seeds, which may or may not be cold-pressed, is used as a cooking oil. Oil made from toasted seeds is used for its distinctive nutty aroma and taste, although it may be unsuitable for frying, which makes it taste burnt and bitter.
Walnut oil is oil extracted from walnuts, Juglans regia. The oil contains polyunsaturated fatty acids, monounsaturated fatty acids, and saturated fats.
Camelina sativa is a flowering plant in the family Brassicaceae usually known as camelina, gold-of-pleasure, or false flax, but also occasionally as wild flax, linseed dodder, German sesame, or Siberian oilseed. It is native to Europe and areas of Central Asia, but cultivated as an oilseed crop mainly in Europe and in North America. It is not related to true flax, in the family Linaceae.
Corn oil or maize oil (British) 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.
Sunflower oil is the non-volatile oil pressed from the seeds of the sunflower. Sunflower oil is commonly used in food as a frying oil, and in cosmetic formulations as an emollient.
Perilla oil is an edible vegetable oil derived from perilla seeds. Having a distinct nutty aroma and taste, the oil pressed from the toasted perilla seeds is used as a flavor enhancer, condiment, and cooking oil in Korean cuisine. The oil pressed from untoasted perilla seeds is used for non-culinary purposes.
Avocado oil is an edible oil extracted from the pulp of avocados, the fruit of Persea americana. It is used as an edible oil both raw and for cooking, where it is noted for its high smoke point. It is also used for lubrication and in cosmetics.
Jatropha curcas is a species of flowering plant in the spurge family, Euphorbiaceae, that is native to the American tropics, most likely Mexico and Central America. It is originally native to the tropical areas of the Americas from Mexico to Argentina, and has been spread throughout the world in tropical and subtropical regions around the world, becoming naturalized or invasive in many areas. The specific epithet, "curcas", was first used by Portuguese doc Garcia de Orta more than 400 years ago. Common names in English include physic nut, Barbados nut, poison nut, bubble bush or purging nut. In parts of Africa and areas in Asia such as India it is often known as "castor oil plant" or "hedge castor oil plant", but it is not the same as the usual castor oil plant, Ricinus communis.
An oil mill is a grinding mill designed to crush or bruise oil-bearing seeds, such as linseed or peanuts, or other oil-rich vegetable material, such as olives or the fruit of the oil palm, which can then be pressed to extract vegetable oils, which may be used as foods or for cooking, as oleochemical feedstocks, as lubricants, or as biofuels. The pomace or press cake – the remaining solid material from which the oil has been extracted – may also be used as a food or fertilizer.
Cooking oil is a plant or animal liquid fat used in frying, baking, and other types of cooking. Oil allows higher cooking temperatures than water, making cooking faster and more flavorful, while likewise distributing heat, reducing burning and uneven cooking. It sometimes imparts its own flavor. Cooking oil is also used in food preparation and flavoring not involving heat, such as salad dressings and bread dips.
Rapeseed oil is one of the oldest known vegetable oils. There are both edible and industrial forms produced from rapeseed, the seed of several cultivars of the plant family Brassicaceae. Historically, it was restricted as a food oil due to its content of erucic acid, which in laboratory studies was shown to be damaging to the cardiac muscle of laboratory animals in high quantities and which imparts a bitter taste, and glucosinolates, which made many parts of the plant less nutritious in animal feed. Rapeseed oil from standard cultivars can contain up to 54% erucic acid.
pistachio oil.
hemp oil.
Office of University Research and Education
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