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Chemistry and processing.



2019-11-13 227 Обсуждений (0)
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Mozhaysk ,  2008


Contents:

Introduction

1. History

2. Chemistry and processing

3. Environmental, social and cultural impact

4. Biofuels and bioproducts

5. Regional production

5.1. Malaysia

5.2. Indonesia

5.3. Australia

5.4. Benin

5.5. Kenya

5.6. Colombia

6. Health

6.1. Blood cholesterol controversy

Bibliography


Introduction.

 

Palm oil is a form of edible vegetable oil obtained from the fruit of the oil palm tree. Previously the second-most widely produced edible oil, after soybean oil, 28 million metric tons were produced worldwide in 2004. It may have now surpassed soybean oil as the most widely produced vegetable oil in the world. It is also an important component of many soaps, washing powders and personal care products, is used to treat wounds, and has controversially found a new use as a feedstock for biofuel.

The palm fruit is the source of both palm oil (extracted from palm fruit) and palm kernel oil (extracted from the fruit seeds). Palm oil itself is reddish because it contains a high amount of beta-carotene. It is used as cooking oil, to make margarine and is a component of many processed foods. Boiling it for a few minutes destroys the carotenoids and the oil becomes colourless. Palm oil is one of the few vegetable oils relatively high in saturated fats (like coconut oil) and thus semi-solid at room temperature.


History.

 

Palm oil (from the African Oil Palm, Elaeis guineensis) was long recognized in West African countries, and among West African peoples it has long been in widespread use as a cooking oil. European merchants trading with West Africa occasionally purchased palm oil for use in Europe, but as the oil was bulky and cheap, palm oil remained rare outside West Africa. In the Asante Confederacy, state-owned slaves built large plantations of oil palm trees, while in the neighbouring Kingdom of Dahomey, King Ghezo passed a law in 1856 forbidding his subjects from cutting down oil palms.

Palm oil became a highly sought-after commodity by British traders, for use as an industrial lubricant for the machines of Britain's Industrial Revolution, as well as forming the basis of soap products, such as Lever Brothers' "Sunlight Soap", and the American Palmolive brand. By c.1870, palm oil constituted the primary export of some West African countries such as Ghana and Nigeria, although this was overtaken by cocoa in the 1880s.

Palm was introduced to Java by the Dutch in 1848 and Malaysia (then the British colony of Malaya) in 1910 by Scotsman William Sime and English banker Henry Darby. The first plantations were mostly established and operated by British plantation owners, such as Sime Darby. From the 1960s a major oil palm plantation scheme was introduced by the government with the main aim of eradicating poverty. Settlers were each allocated 10 acres of land (about 4 hectares) planted either with oil palm or rubber, and given 20 years to pay off the debt for the land.[citation needed] The large plantation companies remained listed in London until the Malaysian government engineered their "Malaysianisation" throughout the 1960s and 1970s.

 


Chemistry and processing.

 

Palm oil and palm kernel oil are composed of fatty acids, esterified with glycerol just like any ordinary fat. Both are high in saturated fatty acids, about 50% and 80%, respectively. The oil palm gives its name to the 16 carbon saturated fatty acid palmitic acid found in palm oil; monounsaturated oleic acid is also a constituent of palm oil while palm kernel oil contains mainly lauric acid. Palm oil is the largest natural source of tocotrienol, part of the vitamin E family. Palm oil is also high in vitamin K and dietary magnesium.

Napalm derives its name from naphthenic acid, palmitic acid and pyrotechnics or simply from a recipe using naphtha and palm oil.

The approximate concentration of fatty acids (FAs) in palm oil is as follows:

Fatty acid content of palm oil

Type of fatty acid    pct   

Palmitic C16     44.3%

Stearic C18   4.6%

Myristic C14    1.0%

Oleic C18   38.7%

Linoleic C18     10.5%

Other/Unknown 0.9%

Fatty acid content of palm kernel oil

Type of fatty acid    pct   

Lauric C12   48.2%

Myristic C14    16.2%

Palmitic C16     8.4%

Capric C10           3.4%

Caprylic C8      3.3%

Stearic C18    2.5%

Oleic C18   15.3%

Linoleic C18      2.3%

Other/Unknown   0.4%

 

Fatty acids are saturated and unsaturated aliphatic carboxylic acids with carbon chain length in the range of C6 up to C24. An example of a fatty acid is palmitic acid

CH3 – (CH2)14 – COOH

Splitting of oils and fats by hydrolysis, or under basic conditions saponification, yields fatty acids; with glycerin(glycerol) as a by-product. The split-off fatty acids are a mixture of fatty acids ranging from C6 to C18 depending on the type of Oil / Fat.

Palm oil products are made using milling and refining processes; first using fractionation, with crystallization and separation processes to obtain a solid stearin, and liquid olein. By melting and degumming, impurities can be removed and then the oil filtered and bleached. Next, physical refining removes odours and colouration, to produce refined bleached deodorized palm oil, or RBDPO, and free pure fatty acids, used as an important raw material in the manufacture of soaps, washing powder and other hygiene and personal care products. RBDPO is the basic oil product which can be sold on the world's commodity markets, although many companies fractionate it out further into palm olein, for cooking oil, or other products.

Palm is also used in biodiesel production, as either a simply-processed palm oil mixed with petrodiesel, or processed through transesterification to create a palm oil methyl ester blend which meets the international EN 14214 specification, with glycerin as a by-product. The actual process used varies between countries and the requirements of any export markets. Second-generation biofuel production processes are also being trialled in relatively small quantities.

 



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