Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Vegetable Oil shopping experience:
1. Compare - without doubt the biggest advantage that the Vegetable Oil offers shoppers today is the ability to compare thousands of Vegetable Oil at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.
2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about
3. Testimonials - don't know anybody that has bought a Vegetable Oil? Wrong! If the Vegetable Oil is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.
4. Questions - Got a question about Vegetable Oil then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....
5. Reputation - Never heard of the company selling Vegetable Oil? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Vegetable Oil and build up a picture of their reputation for sales, returns, customer service, delivery etc.
6. Returns - still worried that even after all of the above your Vegetable Oil wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.
7. Feedback - happy with your Vegetable Oil then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.
8. Security - check for the yellow padlock on the Vegetable Oil site before you buy, and the s after http:/ /i.e. https:// = a secure site
9. Contact - got a question about Vegetable Oil, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.
10. Payment - ready to pay for your Vegetable Oil, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.
Vegetable fats and oils are substances derived from plants that are composed of triglycerides. Nominally, oils are liquid at room temperature, and fats are solid; a dense brittle fat is called a wax. Although many different parts of plants may yield oil, Compare, for example, the Essential oil#Raw Materials from which essential oils are extracted. in actual commercial practice oil is extracted primarily from the
seeds of oilseed plants.
The temperature-based distinction between oils and fats is imprecise, since the temperatures of rooms vary, and typically any one substance has a
melting range instead of a single
melting point.
Triglyceride vegetable fats and oils include not only edible, but also inedible vegetable fats and oils such as processed
linseed oil,
tung oil, and castor oil, used in lubricants, paints, cosmetics, pharmaceuticals, and other industrial purposes. Although thought of as esters of glycerin and a varying blend of fatty acids, in fact these oils contain free fatty acids and diglycerides as well.
Uses of triglyceride vegetable oil
Oils extracted from plants have been used in many cultures, since ancient time. As an example, in a 4,000 year old "kitchen" unearthed in
Indiana's
Charlestown State Park, archaeologist Bob McCullough of Indiana University-Purdue University Fort Wayne found evidence that natives used large slabs of rock to crush hickory nuts, then boiled them in water to extract the oil.
Fatty acids play an important role in the life and death of cardiac cells because they are essential fuels for mechanical and electrical activities of the heart. - see page 1 of this link
Culinary uses
Many vegetable oils are consumed directly, or used directly as ingredients in food - a role that they share with some
fat, including
butter and ghee. The oils serve a number of purposes in this role:
- Texture - oils can serve to make other ingredients stick together less.
- Flavor - while less-flavorful oils command premium prices, oils such as olive oil or almond oil may be chosen specifically for the flavor they impart.
- Flavor base - oils can also "carry" flavors of other ingredients, since many flavors are present in chemicals that are soluble in oil.
Secondly, oils can be heated, and used to cook other foods. Oils that are suitable for this purpose must have a high flash point. Such oils include the major cooking oils -
canola oil,
sunflower oil,
safflower oil, peanut oil etc. Some oils, including rice bran oil, are particularly valued in Asia cultures for high temperature cooking, because of their unusually high flash point.
Hydrogenated oils
Triglyceride-based vegetable fats and oils can be transformed through partial or complete
hydrogenation into fats and oils of higher melting point. The
hydrogenation process involves
"sparging" the oil at high temperature and pressure with hydrogen in the presence of a catalyst, typically a powdered
nickel compound. As each double-bond in the
triglyceride is broken, two hydrogen atoms form single bonds. The elimination of double-bonds by adding hydrogen atoms is called
saturated fat; as the degree of saturated fat increases, the oil progresses towards being fully hydrogenated. An oil may be hydrogenated to increase resistance to Rancidification (oxidation) or to change its physical characteristics. As the degree of saturation increases, the oil's viscosity and melting point increase.
The use of saturated fat in foods has never been completely satisfactory. Because the center arm of the
triglyceride is shielded somewhat by the end
triglycerides, most of the
hydrogenation occurs on the end
triglycerides. This makes the saturated fat more brittle. A margarine made from naturally more saturated tropical oils will be more plastic (more "spreadable") than a margarine made from hydrogenated soy oil. In addition, partial hydrogenation results in the formation of
trans fats, which have increasingly been viewed as unhealthy since the 1970s.
(In the U.S., the United States Department of Agriculture Standard of Identity
for a product labeled as vegetable oil margarine
specifies that only canola, safflower, sunflower, corn, soybean, or peanut oil may be used.{{cite web| url=http://www.ams.usda.gov/dairy/vegoil.pdf#search=%22%22standard%20of%20identity%22%20margarine%22
| title=USDA Standard of Identity
--> Products not labeled vegetable oil margarine
do not have that restriction.)
Industrial uses
Vegetable oils are used as an ingredient or component in many manufactured products.
- Many vegetable oils are used to make soaps, skin products, perfumes and other personal care and cosmetics.
- Some oils are particularly suitable as drying agents, and are used in making paints and other wood treatment products. Dammar oil (a mixture of linseed oil and dammar 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 Electrical insulations as vegetable oils are non-toxic to the environment, biodegradable if spilled and have high flash point and fire points. However, vegetable oils have issues with chemical stability (there has to be a tradeoff with biodegradability), so they are generally used in systems where they are not exposed to oxygen and are more expensive than crude oil distillate. Two examples are FR3 by Cooper Power and Biotemp by ABB. Midel 7131 by M & I materials is a synthetic tetraester, like a vegetable oil but with four fatty acid chains compared to the normal three found in a natural ester, and is manufactured by an alcohol plus acid reaction. Tetraesters generally have high stability to oxidation and have found use as engine lubricants.
- Vegetable oil is being used to produce bio-degradable hydraulic fluid{{cite web
| url=http://www.ars.usda.gov/is/pr/2000/000419.htm
| author=Linda McGraw
| title=Biodegradable Hydraulic Fluid Nears Market
| publisher=USDA
| date=April 19, 2000
| accessdate=2006-09-29
-->and
lubricant.{{cite web| url=http://www.gwrranci.org/gallery/20060824/
| title=Cass Scenic Railroad, West Virginia
| publisher=GWWCA
| accessdate=2007-07-03
-->
- Common vegetable oil has also been used experimentally as a cooling agent in PCs.
One limiting factor in industrial uses of vegetable oils is that all such oils eventually chemically decompose turning Rancidification. Oils that are more stable, such as
Ben oil or
mineral oil, are preferred for some industrial uses.
Vegetable-based oils, like
castor oil, have been used as medicine and as lubricants for a long time. Castor oil has numerous industrial uses, primarily due to the presence of hydroxyl groups on the fatty acid chains. Castor oil, and other vegetable oils which have been chemically modified to contain hydroxyl groups, are becoming increasingly important in the production of polyurethane plastic for many applications. These modified vegetable oils are known as natural oil polyols.
Pet food additive
Vegetable oil is used in 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. In some poorer grade pet foods, the oil is listed only as "vegetable oil", without specifying the particular oil. {{cite web| url=http://www.dogfoodproject.com/index.php?page=badingredients
| title= Ingredients to avoid
| publisher=The Dog Food Project
| accessdate=2007-06-26
-->
Fuel
Vegetable oils are also used to make
biodiesel, which can be used like conventional
diesel. Some vegetable oil blends are used in unmodified vehicles but
straight vegetable oil needs specially prepared vehicles which have a method of heating the oil to reduce its viscosity. The
vegetable oil economy is growing and the availability of
biodiesel around the world is increasing.
Extraction
The "modern" way of processing vegetable oil is by chemical extraction, using solvent extracts, which produces higher yields and is quicker and less expensive. The most common solvent is petroleum-derived hexane. This technique is used for most of the "newer" industrial oils such as soybean and corn oils.
Another way is physical extraction, which does not use solvent extracts. It is made the "traditional" way using several different types of mechanical extraction.{{cite web| url=http://banglapedia.search.com.bd/HT/K_0050.htm
| title=Kalu (oil presser)
| publisher=Banglapedia
| accessdate=2006-11-12
--> This method is typically used to produce the more traditional oils (e.g., olive), and it is preferred by most "health-food" customers in the United States and in Europe. Expeller-pressed extraction is one type, and there are two other types that are both oil presses: the screw press and the ram press (food). Oil seed presses are commonly used in developing countries, among people for whom other extraction methods would be prohibitively expensive. The amount of oil extracted using these methods varies widely, as shown in the following table for extracting mowrah butter in
India:{{cite web| work=Minor oil crops
| publisher=FAO
| title=Illipe
| author=B.L. Axtell from research by R.M. Fairman
| date=1992
| url=http://www.fao.org/es/faodef/fdef14e.htm
| accessdate=2006-11-12
-->
{| class="wikitable"! Method !! Percentage extracted
|-
| Ghani{{cite web
| url=http://banglapedia.search.com.bd/HT/G_0089.htm
| title=Ghani
| publisher=Banglapedia
| accessdate=2006-11-12
--> A ghani is a traditional Indian oil press, driven by a horse or ox. || 20-30%|-
| Expellers || 34-37%
|-
| Solvent || 40-43%
|}
Supercritical carbon dioxide can also be used for the extraction purpose and is non toxic.
Production
Crude oil, straight from the crushing operation, is not considered edible in the case of most oilseeds. The same is true for the remaining meal. For instance, animals fed raw soy meal will waste away, even though soy meal is high in protein. Researchers at Central Soya discovered that a
Trypsin inhibitor in soybeans could be deactivated by toasting the meal, and both licensed their invention, and sold soy meal augmented with vitamins and minerals as MasterMix, a product for farmers to mix with their own grain to produce a high quality feed.
The processing of soy oil is typical of that used with most vegetable oils. Crude soy oil is first mixed with caustic soda. Saponification turns free fatty acids into soap. The soap is removed with a centrifuge. Neutralized dry soap stock (NDSS) is typically used in animal feed, more to get rid of it than because it is particularly nourishing. The remaining oil is deodorized by heating under a near-perfect vacuum and Sparging with water. The condensate is further processed to become vitamin E food supplement, while the oil can be sold to manufacturers and consumers at this point.
Some of the oil is further processed. By carefully filtering the oil at near-freezing temperatures, "winter oil" is produced. This oil is sold to manufacturers of salad dressings, so that the dressings do not turn cloudy when refrigerated.
The oil may be partially
hydrogenation 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.
Another major use of soy oil is for fry oils. These oils require substantial hydrogenation to keep the polyunsaturates of soy oil from becoming rancid.
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, 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) are formed in the hydrogenation reactor, and may amount to as much as 40 percent by weight of a partially hydrogenated oil. Trans acids are increasingly thought to be unhealthy.
Sparging
In the processing of edible oils, the oil is heated under vacuum to near the smoke point, 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.
Particular oils
The following triglyceride vegetable oils account for almost all world-wide 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 2000 was:
{])! Notes|-|
Soybean ] || align="center" | 23.3 || The most widely produced
tropical oil. Also used to make biofuel.] || align="center" | 13.1 || One of the most widely used cooking oils, Canola is a (trademarked) variety (cultivar) of rapeseed.] || align="center" | 8.6 || A common cooking oil, also used to make biodiesel.] || align="center" | 4.2 || Mild-flavored cooking oil.|-|
Cottonseed ] || align="center" | 2.7 || From the
seed of the African palm tree] || align="center" | 2.5 || Used in cooking, cosmetics,
soaps and as a fuel for traditional
oil lamps, or used directly as fuel in [diesel cars which may require modification to heat the oil to reduce its higher viscosity. The suitability of the fuel should come as little surprise, as Rudolph Diesel originally designed his engine to run on peanut oil.
Other significant triglyceride oils include:
- Corn oil, one of the most common, and inexpensive cooking oils.
- Hazelnut oil and other nut oils
- Linseed oil, from flax seeds
- Rice bran oil, from rice grains
- Safflower oil, a flavorless and colorless cooking oil.
- Sesame oil, used as a cooking oil, and as a massage oil, particularly in India.
History of edible vegetable oils in North America
While olive oil and other pressed oils have been around for millennia, Procter & Gamble researchers were innovators when they started selling cottonseed oil as a creamed shortening, in 1911. Ginning mills were happy to have someone haul away the cotton seeds. Procter & Gamble researchers learned how to extract the oil, refine it, partially hydrogenate it (causing it to be solid at room temperature and thus mimic natural lard), and can it 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. (Procter & Gamble sold their fats and oils brands -
Jif and
Crisco - to Smuckers in 2002.)
Soybeans were an exciting new crop from China in the 1930s. Soy was protein-rich, and the light tasteless oil was extremely 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.{{cite web| url=http://www.thehenryford.org/research/services/populartopics/SoybeanCar/default.asp
| title=Soybean Car
| work=Popular Research Topics
| publisher=Benson Ford Research Center
| accessdate=2006-10-23
--> Roger Drackett had a successful new product with
Windex, but he invested heavily in soybean research, seeing it as a smart investment.{{cite news| url=http://www.cincypost.com/living/1999/drack052199.html
| title=Philip W. Drackett: Earned profits, plaudits
| publisher=Cincinnati Post
| author=Barry M. Horstman
| date=May 21, 1999
| accessdate=2006-10-22
--> By the 1950s and 1960s, soybean oil had became the most popular vegetable oil in the US.
In the mid-1970s, Canadian researchers developed a low-erucic rapeseed cultivar. Because the word "rape" was not considered optimal for marketing, they coined the name "canola" (from "Canada Oil"). The
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 mono-unsaturates and is a better source of
omega-3 fats than other popular oils. 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.
Waste oil
As of 2000, the
United States were producing in excess of 11 billion liters of waste vegetable oil annually, mainly from industrial
deep fryers in potato processing plants,
snack food factories and fast food restaurants.
Waste vegetable oil, sold as the commodity yellow grease has a market value of approximately USD1.09 per US
gallon ($0.29/l or $335 per
tonne), expected to rise to $1.21 by 2013, enough to make collection economically viable.
Currently, the largest uses of waste vegetable oil in the U.S. are for animal feed, pet food, and
cosmetics. Since 2002, an increasing number of European Union countries have prohibited the inclusion of waste vegetable oil from catering in animal feed. Waste cooking oils from food manufacturing, however, as well as fresh or unused cooking oil, continues to be used in animal feed.
See also
Notes and references
Other references
- Beare-Rogers, J.L. 1983. "Trans and positional isomers of common fatty acids." In H.H. Draper (ed.) Advances in Nutritional Research. Vol. 5 Plenum Press, New York, pp. 171-200.
- Berry, E.M. and Hirsch, J. 1986. "Does dietary linolenic acid influence blood pressure?" American Journal of Clinical Nutrition. 44: 336-340.
- Beyers, E.C. and Emken, E.A. 1991. "Metabolites of cis, trans, and trans, cis isomers of linoleic acid in mice and incorporation into tissue lipids." Biochimica et Biophysica Acta. 1082: 275-284.
- Birch, D.G., Birch, E.E., Hoffman, D.R., and Uauy, R.D. 1992. "Retinal development in very-low-birth-weight infants fed diets differing in omega-3 fatty acids." Investigative Ophthalmology and Visual Science 33(8): 2365-2376.
- Birch, E.E., Birch, D.G., Hoffman, D.R., and Uauy, R. 1992. "Dietary essential fatty acid supply and visual acuity development." Investigative Ophthalmology and Visual Science. 33(11): 3242-3253.
- Brenner, R.R. 1989. Factors influencing fatty acid chain elongation and desaturation, in the role of fats in human nutrition. 2nd edn. (eds A.J. Vergroesen and M. Crawford), Academic Press, London pp. 45-79.
- British Nutrition Foundation. 1987. Report of the task force on trans fatty acids. London: British Nutrition Foundation.
- Central Soya annual report, 1979.
- Emken, E. A. 1984. "Nutrition and biochemistry of trans and positional fatty acid isomers in hydrogenated oils." Annual Reviews of Nutrition. 4: 339-376.
- Enig, M.G., Atal, S., Keeney, M and Sampugna, J. 1990. "Isomeric trans fatty acids in the U.S. diet." Journal of the American College of Nutrition. 9: 471-486.
- Ascherio, A., Hennekens, C.H., Baring, J.E., Master, C., Stampfer, M.J. and Willett, W.C. 1994. "Trans fatty acids intake and risk of myocardial infarction." Circulation. 89: 94-101.
- Gurr, M.I. 1983. "Trans fatty acids: Metabolic and nutritional significance." Bulletin of the International Dairy Federation. Document 166: 5-18.
- Hui Y. H., editor, "Bailey's Industrial Oil and Fat Products," Edible Oil and Fat Products
- Koletzko, B. 1992. "Trans fatty acids may impair biosynthesis of long-chain polyunsaturates and growth in man." Acta Paediatrica. 81: 302-306.
- Lief, Alfred, It floats: The story of Procter & Gamble, published 1958 by Rinehart.
- MacMillen, Harold W., Mr. Mac and Central Soya: the foodpower story, published 1967 by Newcomen Society
- Marchand, C.M. 1982. "Positional isomers of trans-octadecenoic acids in margarine." Canadian Institute of Food Science and Technology Journal. 15: 196-199.
- Mensink, R.P., Zock, P.L., Katan, M.B. and Hornstra, G. 1992. "Effect of dietary cis-and trans-fatty acids on serum lipoprotein levels in humans." Journal of Lipid Research. 33: 1493-1501.
- Siguel, E.N. and Lerman, R.H. 1993. "Trans fatty acid patterns in patients with angiographically documented coronary artery disease." American Journal of Cardiology. 71: 916-920.
- Troisi, R., Willett, W.C. and Weiss, S.T. 1992. "Trans-fatty acid intake in relation to serum lipid concentrations in adult men." American Journal of Clinical Nutrition. 56: 1019-1024.
- Willett, W.C., Stampfer, M.J., Manson, J.E., Colditz, G.A., Speizer, F.E., Rosner, B.A., Sampson, L.A. and Hennekens, C.H. 1993. "Intake of trans fatty acids and risk of coronary heart disease among women." The Lancet. 341: 581-585.
External links
| url=http://www.hydrosafe.com/
| title=Hydro Safe Biodegradable Oil
| publisher=Hydrosafe
-->
| url=http://www.hyfoma.com/en/content/food-branches-processing-manufacturing/oil-margarines-sauces/oil-fats/process_description.html
| title=Edible Oils
| publisher=[Hyfoma
| accessdate=2006-11-05
-->
| url=http://journeytoforever.org/biodiesel_yield.html
| title=Oil yields and characteristics
| publisher=Journey to forever
| accessdate=2006-11-05
-->
| url=http://www.vegetableoildiesel.co.uk/forum/index.php
| title=Vegetable oils as fuel forum
| publisher=UK Goat Industries
| accessdate=2006-11-05
-->
| url=http://www.nnfcc.co.uk/products/oil/oindex.cfm
| publisher=National Non Food Crops Centre
| title=Oil Crops
| accessdate=2006-11-05
--> Information on the use of vegetable oils in fuel, lubricants, polymers, solvents and surfactants.
Vegetable fats and oils are substances derived from plants that are composed of triglycerides. Nominally, oils are liquid at room temperature, and fats are solid; a dense brittle fat is called a
wax. Although many different parts of plants may yield oil, Compare, for example, the Essential oil#Raw Materials from which
essential oils are extracted. in actual commercial practice oil is extracted primarily from the
seeds of oilseed plants.
The temperature-based distinction between oils and fats is imprecise, since the temperatures of rooms vary, and typically any one substance has a
melting range instead of a single
melting point.
Triglyceride vegetable fats and oils include not only edible, but also inedible vegetable fats and oils such as processed linseed oil,
tung oil, and
castor oil, used in lubricants, paints, cosmetics, pharmaceuticals, and other industrial purposes. Although thought of as
esters of glycerin and a varying blend of fatty acids, in fact these oils contain free fatty acids and diglycerides as well.
Uses of triglyceride vegetable oil
Oils extracted from plants have been used in many cultures, since ancient time. As an example, in a 4,000 year old "kitchen" unearthed in Indiana's
Charlestown State Park, archaeologist Bob McCullough of Indiana University-Purdue University Fort Wayne found evidence that natives used large slabs of rock to crush
hickory nuts, then boiled them in water to extract the oil.
Fatty acids play an important role in the life and death of cardiac cells because they are essential fuels for mechanical and electrical activities of the heart. - see page 1 of this link
Culinary uses
Many vegetable oils are consumed directly, or used directly as ingredients in food - a role that they share with some fat, including butter and
ghee. The oils serve a number of purposes in this role:
- Texture - oils can serve to make other ingredients stick together less.
- Flavor - while less-flavorful oils command premium prices, oils such as olive oil or almond oil may be chosen specifically for the flavor they impart.
- Flavor base - oils can also "carry" flavors of other ingredients, since many flavors are present in chemicals that are soluble in oil.
Secondly, oils can be heated, and used to cook other foods. Oils that are suitable for this purpose must have a high flash point. Such oils include the major cooking oils - canola oil,
sunflower oil,
safflower oil, peanut oil etc. Some oils, including
rice bran oil, are particularly valued in Asia cultures for high temperature cooking, because of their unusually high flash point.
Hydrogenated oils
Triglyceride-based vegetable fats and oils can be transformed through partial or complete
hydrogenation into fats and oils of higher melting point. The
hydrogenation process involves
"sparging" the oil at high temperature and pressure with hydrogen in the presence of a catalyst, typically a powdered nickel compound. As each double-bond in the triglyceride is broken, two hydrogen atoms form single bonds. The elimination of double-bonds by adding hydrogen atoms is called
saturated fat; as the degree of saturated fat increases, the oil progresses towards being fully hydrogenated. An oil may be hydrogenated to increase resistance to Rancidification (oxidation) or to change its physical characteristics. As the degree of saturation increases, the oil's viscosity and melting point increase.
The use of saturated fat in foods has never been completely satisfactory. Because the center arm of the
triglyceride is shielded somewhat by the end triglycerides, most of the
hydrogenation occurs on the end
triglycerides. This makes the
saturated fat more brittle. A margarine made from naturally more saturated tropical oils will be more plastic (more "spreadable") than a margarine made from hydrogenated soy oil. In addition, partial hydrogenation results in the formation of trans fats, which have increasingly been viewed as unhealthy since the 1970s.
(In the U.S., the United States Department of Agriculture Standard of Identity for a product labeled as vegetable oil margarine
specifies that only canola, safflower, sunflower, corn, soybean, or peanut oil may be used.{{cite web| url=http://www.ams.usda.gov/dairy/vegoil.pdf#search=%22%22standard%20of%20identity%22%20margarine%22
| title=USDA Standard of Identity
--> Products not labeled vegetable oil margarine
do not have that restriction.)
Industrial uses
Vegetable oils are used as an ingredient or component in many manufactured products.
- Many vegetable oils are used to make soaps, skin products, perfumes and other personal care and cosmetics.
- Some oils are particularly suitable as drying agents, and are used in making paints and other wood treatment products. Dammar oil (a mixture of linseed oil and dammar 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 Electrical insulations as vegetable oils are non-toxic to the environment, biodegradable if spilled and have high flash point and fire points. However, vegetable oils have issues with chemical stability (there has to be a tradeoff with biodegradability), so they are generally used in systems where they are not exposed to oxygen and are more expensive than crude oil distillate. Two examples are FR3 by Cooper Power and Biotemp by ABB. Midel 7131 by M & I materials is a synthetic tetraester, like a vegetable oil but with four fatty acid chains compared to the normal three found in a natural ester, and is manufactured by an alcohol plus acid reaction. Tetraesters generally have high stability to oxidation and have found use as engine lubricants.
- Vegetable oil is being used to produce bio-degradable hydraulic fluid{{cite web
| url=http://www.ars.usda.gov/is/pr/2000/000419.htm
| author=Linda McGraw
| title=Biodegradable Hydraulic Fluid Nears Market
| publisher=USDA
| date=April 19, 2000
| accessdate=2006-09-29
-->and
lubricant.{{cite web| url=http://www.gwrranci.org/gallery/20060824/
| title=Cass Scenic Railroad, West Virginia
| publisher=GWWCA
| accessdate=2007-07-03
-->
- Common vegetable oil has also been used experimentally as a cooling agent in PCs.
One limiting factor in industrial uses of vegetable oils is that all such oils eventually chemically decompose turning
Rancidification. Oils that are more stable, such as Ben oil or mineral oil, are preferred for some industrial uses.
Vegetable-based oils, like
castor oil, have been used as medicine and as lubricants for a long time. Castor oil has numerous industrial uses, primarily due to the presence of
hydroxyl groups on the fatty acid chains. Castor oil, and other vegetable oils which have been chemically modified to contain hydroxyl groups, are becoming increasingly important in the production of polyurethane plastic for many applications. These modified vegetable oils are known as
natural oil polyols.
Pet food additive
Vegetable oil is used in 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. In some poorer grade pet foods, the oil is listed only as "vegetable oil", without specifying the particular oil. {{cite web| url=http://www.dogfoodproject.com/index.php?page=badingredients
| title= Ingredients to avoid
| publisher=The Dog Food Project
| accessdate=2007-06-26
-->
Fuel
Vegetable oils are also used to make biodiesel, which can be used like conventional
diesel. Some vegetable oil blends are used in unmodified vehicles but
straight vegetable oil needs specially prepared vehicles which have a method of heating the oil to reduce its viscosity. The vegetable oil economy is growing and the availability of biodiesel around the world is increasing.
Extraction
The "modern" way of processing vegetable oil is by chemical extraction, using solvent extracts, which produces higher yields and is quicker and less expensive. The most common solvent is petroleum-derived
hexane. This technique is used for most of the "newer" industrial oils such as soybean and corn oils.
Another way is physical extraction, which does not use solvent extracts. It is made the "traditional" way using several different types of mechanical extraction.{{cite web| url=http://banglapedia.search.com.bd/HT/K_0050.htm
| title=Kalu (oil presser)
| publisher=Banglapedia
| accessdate=2006-11-12
--> This method is typically used to produce the more traditional oils (e.g., olive), and it is preferred by most "health-food" customers in the
United States and in
Europe. Expeller-pressed extraction is one type, and there are two other types that are both oil presses: the screw press and the
ram press (food). Oil seed presses are commonly used in developing countries, among people for whom other extraction methods would be prohibitively expensive. The amount of oil extracted using these methods varies widely, as shown in the following table for extracting mowrah butter in
India:{{cite web| work=Minor oil crops
| publisher=FAO
| title=Illipe
| author=B.L. Axtell from research by R.M. Fairman
| date=1992
| url=http://www.fao.org/es/faodef/fdef14e.htm
| accessdate=2006-11-12
-->
{| class="wikitable"! Method !! Percentage extracted
|-
| Ghani{{cite web
| url=http://banglapedia.search.com.bd/HT/G_0089.htm
| title=Ghani
| publisher=Banglapedia
| accessdate=2006-11-12
--> A ghani is a traditional Indian oil press, driven by a horse or ox. || 20-30%|-
| Expellers || 34-37%
|-
| Solvent || 40-43%
|}
Supercritical carbon dioxide can also be used for the extraction purpose and is non toxic.
Production
Crude oil, straight from the crushing operation, is not considered edible in the case of most oilseeds. The same is true for the remaining meal. For instance, animals fed raw soy meal will waste away, even though soy meal is high in protein. Researchers at Central Soya discovered that a Trypsin inhibitor in soybeans could be deactivated by toasting the meal, and both licensed their invention, and sold soy meal augmented with vitamins and minerals as MasterMix, a product for farmers to mix with their own grain to produce a high quality feed.
The processing of soy oil is typical of that used with most vegetable oils. Crude soy oil is first mixed with caustic soda.
Saponification turns free fatty acids into soap. The soap is removed with a centrifuge. Neutralized dry soap stock (NDSS) is typically used in animal feed, more to get rid of it than because it is particularly nourishing. The remaining oil is deodorized by heating under a near-perfect
vacuum and
Sparging with water. The condensate is further processed to become vitamin E food supplement, while the oil can be sold to manufacturers and consumers at this point.
Some of the oil is further processed. By carefully filtering the oil at near-freezing temperatures, "winter oil" is produced. This oil is sold to manufacturers of salad dressings, so that the dressings do not turn cloudy when refrigerated.
The oil may be partially hydrogenation 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.
Another major use of soy oil is for fry oils. These oils require substantial hydrogenation to keep the polyunsaturates of soy oil from becoming rancid.
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, 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) are formed in the hydrogenation reactor, and may amount to as much as 40 percent by weight of a partially hydrogenated oil. Trans acids are increasingly thought to be unhealthy.
Sparging
In the processing of edible oils, the oil is heated under vacuum to near the smoke point, 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.
Particular oils
The following triglyceride vegetable oils account for almost all world-wide 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 2000 was:
{])! Notes|-|
Soybean ] || align="center" | 23.3 || The most widely produced
tropical oil. Also used to make biofuel.] || align="center" | 13.1 || One of the most widely used cooking oils,
Canola is a (trademarked) variety (cultivar) of rapeseed.] || align="center" | 8.6 || A common cooking oil, also used to make biodiesel.] || align="center" | 4.2 || Mild-flavored cooking oil.|-|
Cottonseed ] || align="center" | 2.7 || From the
seed of the African palm tree] || align="center" | 2.5 || Used in
cooking, cosmetics,
soaps and as a fuel for traditional
oil lamps, or used directly as fuel in [diesel cars which may require modification to heat the oil to reduce its higher
viscosity. The suitability of the fuel should come as little surprise, as
Rudolph Diesel originally designed his engine to run on
peanut oil.
Other significant triglyceride oils include:
- Corn oil, one of the most common, and inexpensive cooking oils.
- Hazelnut oil and other nut oils
- Linseed oil, from flax seeds
- Rice bran oil, from rice grains
- Safflower oil, a flavorless and colorless cooking oil.
- Sesame oil, used as a cooking oil, and as a massage oil, particularly in India.
History of edible vegetable oils in North America
While olive oil and other pressed oils have been around for millennia,
Procter & Gamble researchers were innovators when they started selling cottonseed oil as a creamed shortening, in 1911.
Ginning mills were happy to have someone haul away the cotton seeds. Procter & Gamble researchers learned how to extract the oil, refine it, partially hydrogenate it (causing it to be solid at room temperature and thus mimic natural lard), and can it 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. (Procter & Gamble sold their fats and oils brands -
Jif and
Crisco - to
Smuckers in 2002.)
Soybeans were an exciting new crop from China in the 1930s. Soy was protein-rich, and the light tasteless oil was extremely 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.{{cite web| url=http://www.thehenryford.org/research/services/populartopics/SoybeanCar/default.asp
| title=Soybean Car
| work=Popular Research Topics
| publisher=Benson Ford Research Center
| accessdate=2006-10-23
--> Roger Drackett had a successful new product with Windex, but he invested heavily in soybean research, seeing it as a smart investment.{{cite news| url=http://www.cincypost.com/living/1999/drack052199.html
| title=Philip W. Drackett: Earned profits, plaudits
| publisher=Cincinnati Post
| author=Barry M. Horstman
| date=May 21, 1999
| accessdate=2006-10-22
--> By the 1950s and 1960s, soybean oil had became the most popular vegetable oil in the US.
In the mid-1970s, Canadian researchers developed a low-erucic rapeseed cultivar. Because the word "rape" was not considered optimal for marketing, they coined the name "canola" (from "Canada Oil"). The
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 mono-unsaturates and is a better source of omega-3 fats than other popular oils. 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.
Waste oil
As of 2000, the United States were producing in excess of 11 billion liters of waste vegetable oil annually, mainly from industrial deep fryers in
potato processing plants,
snack food factories and fast food restaurants.
Waste vegetable oil, sold as the commodity yellow grease has a
market value of approximately USD1.09 per US
gallon ($0.29/l or $335 per
tonne), expected to rise to $1.21 by 2013, enough to make collection economically viable.
Currently, the largest uses of waste vegetable oil in the U.S. are for
animal feed, pet food, and cosmetics. Since 2002, an increasing number of
European Union countries have prohibited the inclusion of
waste vegetable oil from catering in animal feed. Waste cooking oils from food manufacturing, however, as well as fresh or unused cooking oil, continues to be used in animal feed.
See also
- Fragrance oil
- Essential oils
- List of vegetable oils
- List of macerated oils
- Algae culture
- Biodiesel
- Non food crops
- Straight vegetable oil
- Cooking oil
- Decorticator
- Expeller
- Extruder
- Lipid
- Mill (factory)
- Deodoriser
- Fatty Acid
- Oleochemistry
Notes and references
Other references
- Beare-Rogers, J.L. 1983. "Trans and positional isomers of common fatty acids." In H.H. Draper (ed.) Advances in Nutritional Research. Vol. 5 Plenum Press, New York, pp. 171-200.
- Berry, E.M. and Hirsch, J. 1986. "Does dietary linolenic acid influence blood pressure?" American Journal of Clinical Nutrition. 44: 336-340.
- Beyers, E.C. and Emken, E.A. 1991. "Metabolites of cis, trans, and trans, cis isomers of linoleic acid in mice and incorporation into tissue lipids." Biochimica et Biophysica Acta. 1082: 275-284.
- Birch, D.G., Birch, E.E., Hoffman, D.R., and Uauy, R.D. 1992. "Retinal development in very-low-birth-weight infants fed diets differing in omega-3 fatty acids." Investigative Ophthalmology and Visual Science 33(8): 2365-2376.
- Birch, E.E., Birch, D.G., Hoffman, D.R., and Uauy, R. 1992. "Dietary essential fatty acid supply and visual acuity development." Investigative Ophthalmology and Visual Science. 33(11): 3242-3253.
- Brenner, R.R. 1989. Factors influencing fatty acid chain elongation and desaturation, in the role of fats in human nutrition. 2nd edn. (eds A.J. Vergroesen and M. Crawford), Academic Press, London pp. 45-79.
- British Nutrition Foundation. 1987. Report of the task force on trans fatty acids. London: British Nutrition Foundation.
- Central Soya annual report, 1979.
- Emken, E. A. 1984. "Nutrition and biochemistry of trans and positional fatty acid isomers in hydrogenated oils." Annual Reviews of Nutrition. 4: 339-376.
- Enig, M.G., Atal, S., Keeney, M and Sampugna, J. 1990. "Isomeric trans fatty acids in the U.S. diet." Journal of the American College of Nutrition. 9: 471-486.
- Ascherio, A., Hennekens, C.H., Baring, J.E., Master, C., Stampfer, M.J. and Willett, W.C. 1994. "Trans fatty acids intake and risk of myocardial infarction." Circulation. 89: 94-101.
- Gurr, M.I. 1983. "Trans fatty acids: Metabolic and nutritional significance." Bulletin of the International Dairy Federation. Document 166: 5-18.
- Hui Y. H., editor, "Bailey's Industrial Oil and Fat Products," Edible Oil and Fat Products
- Koletzko, B. 1992. "Trans fatty acids may impair biosynthesis of long-chain polyunsaturates and growth in man." Acta Paediatrica. 81: 302-306.
- Lief, Alfred, It floats: The story of Procter & Gamble, published 1958 by Rinehart.
- MacMillen, Harold W., Mr. Mac and Central Soya: the foodpower story, published 1967 by Newcomen Society
- Marchand, C.M. 1982. "Positional isomers of trans-octadecenoic acids in margarine." Canadian Institute of Food Science and Technology Journal. 15: 196-199.
- Mensink, R.P., Zock, P.L., Katan, M.B. and Hornstra, G. 1992. "Effect of dietary cis-and trans-fatty acids on serum lipoprotein levels in humans." Journal of Lipid Research. 33: 1493-1501.
- Siguel, E.N. and Lerman, R.H. 1993. "Trans fatty acid patterns in patients with angiographically documented coronary artery disease." American Journal of Cardiology. 71: 916-920.
- Troisi, R., Willett, W.C. and Weiss, S.T. 1992. "Trans-fatty acid intake in relation to serum lipid concentrations in adult men." American Journal of Clinical Nutrition. 56: 1019-1024.
- Willett, W.C., Stampfer, M.J., Manson, J.E., Colditz, G.A., Speizer, F.E., Rosner, B.A., Sampson, L.A. and Hennekens, C.H. 1993. "Intake of trans fatty acids and risk of coronary heart disease among women." The Lancet. 341: 581-585.
External links
| url=http://www.hydrosafe.com/
| title=Hydro Safe Biodegradable Oil
| publisher=Hydrosafe
-->
| url=http://www.hyfoma.com/en/content/food-branches-processing-manufacturing/oil-margarines-sauces/oil-fats/process_description.html
| title=Edible Oils
| publisher=[Hyfoma
| accessdate=2006-11-05
-->
| url=http://journeytoforever.org/biodiesel_yield.html
| title=Oil yields and characteristics
| publisher=Journey to forever
| accessdate=2006-11-05
-->
| url=http://www.vegetableoildiesel.co.uk/forum/index.php
| title=Vegetable oils as fuel forum
| publisher=UK Goat Industries
| accessdate=2006-11-05
-->
| url=http://www.nnfcc.co.uk/products/oil/oindex.cfm
| publisher=National Non Food Crops Centre
| title=Oil Crops
| accessdate=2006-11-05
--> Information on the use of vegetable oils in fuel, lubricants, polymers, solvents and surfactants.
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What's In Vegetable Oil?
Vegetable oil is just vegetable oil, isn't it? Well, the answer to this is it's not. Most vegetable oil production involves the use of various chemicals.
