Plant fats and oils are lipid materials derived from plants. Physically, oils are liquid at room temperature, and fats are solid. Chemically, both fats and oils are composed of triglycerides, as contrasted with waxes which lack glycerin in their structure. Although many plant parts may yield oil, in commercial practice, oil is extracted primarily from seeds.
Vegetable fats and oils may or may not be edible. Examples of inedible vegetable fats and oils include processed linseed oil, tung oil, and castor oil used in lubricants, paints, cosmetics, pharmaceuticals, and other industrial applications.
Cooking oils[edit | edit source]
General cooking oils[edit | edit source]
Several oils are used as general cooking oils. Note that each specific cooking oil has a specific heat tolerance (high or low smoke point). When choosing a cooking oil, it is important to match the oil's heat tolerance with the cooking method; this due to health reasons.
Oils that are suitable for high-temperature frying (above 230 °C or 446 °F) are:
- Avocado oil
- Corn oil
- Mustard oil
- Palm oil
- Peanut oil (marketed as "groundnut oil" in the UK and India)
- Rice bran oil
- Safflower oil
- Sesame oil (semi-refined)
- Soybean oil
- Sunflower oil
Oils suitable for medium-temperature frying (above 190 °C or 374 °F) include:[citation needed]
- Almond oil
- Cottonseed oil
- Diacylglycerol (DAG) oil
- Ghee, Clarified butter
- Grape seed oil
- Lard
- Olive oil (Virgin, and refined)
- Rapeseed oil, (marketed Canola oil in North America or, sometimes, simply "vegetable oil" in the UK)
- Mustard oil
- Walnut oil
Speciality cooking oils: nut oils[edit | edit source]
Nut oils are generally used in cooking, for their flavor. Most are quite costly, because of the difficulty of extracting the oil.
- Almond oil, used as an edible oil, but primarily in the manufacture of cosmetics.
- Beech nut oil, from Fagus sylvatica nuts, is a well-regarded edible oil in Europe, used for salads and cooking.
- Cashew oil, somewhat comparable to olive oil. May have value for fighting dental cavities.
- Hazelnut oil, mainly used for its flavor. Also used in skin care, because of its slight astringent nature.
- Macadamia oil, with a mild nutty flavor and a high smoke point.
- Mongongo nut oil (or manketti oil), from the seeds of the Schinziophyton rautanenii, a tree which grows in South Africa. High in vitamin E. Also used in skin care.
- Pecan oil, valued as a food oil, but requiring fresh pecans for good quality oil.
- Pine nut oil, sold as a gourmet cooking oil
- Pistachio oil, a strongly flavored oil with a distinctive green color.
- Walnut oil, used for its flavor, also used by Renaissance painters in oil paints.
Speciality cooking oils: citrus oils[edit | edit source]
A number of citrus plants yield pressed oils. Some, like lemon and orange oil, are used as essential oils, which is uncommon for pressed oils. The seeds of many if not most members of the citrus family yield usable oils.
- Grapefruit seed oil, extracted from the seeds of grapefruit (Citrus × paradisi). Grapefruit seed oil was extracted experimentally in 1930 and was shown to be suitable for making soap.
- Lemon oil, similar in fragrance to the fruit. One of a small number of cold pressed essential oils.
- Orange oil, like lemon oil, cold pressed rather than distilled.
Speciality cooking oils: melon and gourd seed oils[edit | edit source]
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.[1]
- Bitter gourd oil, from the seeds of Momordica charantia. High in α-Eleostearic acid. Of current research interest for its potential anti-carcinogenic properties.
- Bottle gourd oil, extracted from the seeds of the Lagenaria siceraria, widely grown in tropical regions. Used as an edible oil.
- Buffalo gourd oil, from the seeds of the Cucurbita foetidissima, a vine with a rank odor, native to southwest North America.
- Butternut squash seed oil, from the seeds of Cucurbita moschata, has a nutty flavor that is used for salad dressings, marinades, and sautéeing.
- Egusi seed oil, from the seeds of Cucumeropsis mannii naudin, is particularly rich in linoleic acid.
- Pumpkin seed oil, a specialty cooking oil, produced in Austria, Slovenia and Croatia. Used mostly in salad dressings.
- Watermelon seed oil, pressed from the seeds of Citrullus vulgaris. Traditionally used in cooking in West Africa.
Speciality cooking oils: other oils[edit | edit source]
- Açaí oil, from the fruit of several species of the Açaí palm (Euterpe) grown in the Amazon region.
- Black seed oil, pressed from Nigella sativa seeds, has a long history of medicinal use, including in ancient Greek, Asian, and Islamic medicine, as well as a topic of current medical research.
- Blackcurrant seed oil, from the seeds of Ribes nigrum, used as a food supplement. High in gamma-Linolenic, omega-3 and omega-6 fatty acids.
- Borage seed oil, from the seeds of Borago officinalis, with an omega-3 content comparable to blackcurrant seed oil and evening primrose oil.
- Flaxseed oil (called linseed oil when used as a drying oil), from the seeds of Linum usitatissimum. High in omega-3 and lignans, which can be used medicinally. A good dietary equivalent to fish oil.
- Amaranth oil, from the seeds of grain amaranth species, including Amaranthus cruentus and Amaranthus hypochondriacus, high in squalene and unsaturated fatty acids.
- Apricot oil, similar to almond oil, which it resembles. Used in cosmetics.
- Apple seed oil, high in linoleic acid.
- Argan oil, from the seeds of the Argania spinosa, is a food oil from Morocco
- Avocado oil, an edible oil
- Ben oil, extracted from the seeds of the Moringa oleifera. High in behenic acid. Extremely stable edible oil. Also suitable for biofuel.
- Borneo tallow nut oil, extracted from the fruit of species of genus Shorea. Used as a substitute for cocoa butter, and to make soap, candles, cosmetics and medicines in places where the tree is common.
- Cape chestnut oil, also called yangu oil, is a popular oil in Africa for skin care.
- Carob pod oil (Algaroba oil), from carob, with an exceptionally high essential fatty acid content.
- Cocoa butter, from the cacao plant. Used in the manufacture of chocolate, as well as in some cosmetics.
- Cocklebur oil, from species of genus Xanthium, with similar properties to poppyseed oil, similar in taste and smell to sunflower oil.
- Cohune oil, from the Attalea cohune (cohune palm) used as a lubricant, for cooking, soapmaking and as a lamp oil.
- Coriander seed oil, from coriander seeds, used in a wide variety of flavoring applications, including gin and seasoning blends.
- Dika oil, from Irvingia gabonensis seeds, native to West Africa. Used to make margarine, soap and pharmaceuticals, where is it being examined as a tablet lubricant. Largely underdeveloped.
- False flax oil made of the seeds of Camelina sativa. One of the earliest oil crops, dating back to the 6th millennium B.C.
- Hemp oil, a high quality food oil
- Kapok seed oil, from the seeds of Ceiba pentandra, used as an edible oil, and in soap production.
- Kenaf seed oil, from the seeds of Hibiscus cannabinus. An edible oil similar to cottonseed oil, with a long history of use.
- Lallemantia oil, from the seeds of Lallemantia iberica, discovered at archaeological sites in northern Greece.
- Mafura oil, extracted from the seeds of Trichilia emetica. Used as an edible oil in Ethiopia. Mafura butter, extracted as part of the same process when extracting the oil, is not edible, and is used in soap and candle making, as a body ointment, as fuel, and medicinally.
- Marula oil, extracted from the kernel of Sclerocarya birrea. Used as an edible oil with a light, nutty flavor. Also used in soaps. Fatty acid composition is similar to that of olive oil.
- Meadowfoam seed oil, highly stable oil, with over 98% long-chain fatty acids. Competes with rapeseed oil for industrial applications.
- Nutmeg butter, extracted by expression from the fruit of cogeners of genus Myristica. Nutmeg butter has a large amount of trimyristin. Nutmeg oil, by contrast, is an essential oil, extracted by steam distillation.
- Okra seed oil, from Abelmoschus esculentus. Composed predominantly of oleic and linoleic acids.
- Papaya seed oil, high in omega-3 and omega-6, similar in composition to olive oil.
- Perilla seed oil, high in omega-3 fatty acids. Used as an edible oil, for medicinal purposes in Asian herbal medicine, in skin care products and as a drying oil.
- Persimmon seed oil, extracted from the seeds of Diospyros virginiana. Dark, reddish brown color, similar in taste to olive oil. Nearly equal content of oleic and linoleic acids.
- Pequi oil, extracted from the seeds of Caryocar brasiliense. Used in Brazil as a highly prized cooking oil.
- Pili nut oil, extracted from the seeds of Canarium ovatum. Used in the Philippines as an edible oil, as well as for a lamp oil.
- Pomegranate seed oil, from Punica granatum seeds, is very high in punicic acid (which takes its name from pomegranates). A topic of current medical research for treating and preventing cancer.
- Quinoa oil, similar in composition and use to corn oil.
- Ramtil oil, pressed from the seeds of the one of several species of genus Guizotia abyssinica (Niger pea) in India and Ethiopia.
- Rice bran oil is a highly stable cooking and salad oil, suitable for high-temperature cooking.
- Royle oil, pressed from the seeds of Prinsepia utilis, a wild, edible oil shrub that grows in the higher Himalayas. Used medicinally in Nepal.
- Sacha inchi oil, from the Peruvian Amazon. High in behenic, omega-3 and omega-6 fatty acids.
- Sapote oil, used as a cooking oil in Guatemala.
- Seje oil, from the seeds of Jessenia bataua. Used in South America as an edible oil, similar to olive oil, as well as for soaps and in the cosmetics industry.
- Shea butter, much of which is produced by poor, African women. Used primarily in skin care products and as a substitute for cocoa butter in confections and cosmetics.
- Taramira oil, from the seeds of the arugula (Eruca sativa), grown in West Asia and Northern India. Used as a (pungent) edible oil after aging to remove acridity.
- Tea seed oil (Camellia oil), widely used in southern China as a cooking oil. Also used in making soaps, hair oils and a variety of other products.
- Tigernut oil (or nut-sedge oil) is pressed from the tuber of Cyperus esculentus. It has properties similar to soybean, sunflower and rapeseed oils.
- Tobacco seed oil, from the seeds of Nicotiana tabacum and other Nicotiana species. If purified, is suitable for edible purposes.
- Tomato seed oil is a potentially valuable by-product, as a cooking oil, from the waste seeds generated from processing tomatoes.
- Wheat germ oil, used nutritionally and in cosmetic preparations
Oils used for biofuel[edit | edit source]
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. (ie as ethanol, methanol and butanol)
Although diesel engines were invented, in part, with vegetable oil in mind, diesel fuel is almost exclusively petroleum-based. Vegetable oils are evaluated for use as a biofuel based on:
- Suitability as a fuel, based on flash point, energy content, viscosity, combustion products and other factors
- Cost, based in part on yield, effort required to grow and harvest, and post-harvest processing cost
Multipurpose oils also used as biofuel[edit | edit source]
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.
- Castor oil, lower cost than many candidates. Kinematic viscosity may be an issue.
- Coconut oil, a cooking oil, with medical and industrial applications as well. Extracted from the kernel or meat of the fruit of the coconut palm. Common in the tropics, and unusual in composition, with medium chain fatty acids dominant.
- Colza oil, from Brassica rapa, var. oleifera (turnip) is closely related to rapeseed (or canola) oil. It is a major source of biodiesel in Germany.
- Corn oil, appealing because of the abundance of maize as a crop.
- Cottonseed oil, the subject of study for cost-effectiveness as a biodiesel feedstock.
- False flax oil, from Camelina sativa, used in Europe in oil lamps until the 18th century.
- Hemp oil, relatively low in emissions. Production is problematic in some countries because of its association with marijuana.
- Mustard oil, shown to be comparable to Canola oil as a biofuel.
- Palm oil, very popular for biofuel, but the environmental impact from growing large quantities of oil palms has recently called the use of palm oil into question.
- Peanut oil, used in one of the first demonstrations of the Diesel engine in 1900.
- Radish oil. Wild radish contains up to 48% oil, making it appealing as a fuel.
- Ramtil oil, used for lighting in India.
- Rice bran oil, appealing because of lower cost than many other vegetable oils. Widely grown in Asia.
- Safflower oil, explored recently as a biofuel in Montana.
- Salicornia oil, from the seeds of Salicornia bigelovii, a halophyte (salt-loving plant) native to Mexico.
- Soybean oil, not economical as a fuel crop, but appealing as a byproduct of soybean crops for other uses.
- Sunflower oil, suitable as a fuel, but not necessarily cost effective.
- Tigernut oil has been described by researchers in China as having "great potential as a biodiesel fuel."
- Tung oil, referenced in several lists of vegetable oils that are suitable for biodiesel.
Inedible oils used only or primarily as biofuel[edit | edit source]
These oils are extracted from plants that are cultivated solely for producing oil-based biofuel.[2] These, plus the major oils described above, have received much more attention as fuel oils than other plant oils.
- Copaiba, an oleoresin tapped from species of genus Copaifera. Used in Brazil as a cosmetic product and a major source of biodiesel.
- Honge oil (Pongamia), pioneered as a biofuel by Udipi Shrinivasa in Bangalore, India.
- Jatropha oil, widely used in India as a fuel oil. Has attracted strong proponents for use as a biofuel.
- Jojoba oil, from the Simmondsia chinensis, a desert shrub.
- Milk bush, popularized by chemist Melvin Calvin in the 1950s. Researched in the 1980s by Petrobras, the Brazilian national petroleum company.
- Nahor oil, pressed from the kernels of Mesua ferrea, is used in India as a lamp oil.
- Paradise oil, from the seeds of Simarouba glauca, has received interest in India as a feed stock for biodiesel.
- Petroleum nut oil, from the Petroleum nut (Pittosporum resiniferum) native to the Philippines. The Philippine government once explored the use of the petroleum nut as a biofuel.
