SUGAR Any of a class of sweet-tasting carbohydrates, formed naturally in the leaves of numerous plants, but concentrated mainly in their roots, stems or fruits. The plants’ energy reserve may be in the form of simple sugars or high-molecular weight polymers of simple sugars (known as starch)sugar an be extracted from the maple tree, the teddy, palmyra, coconut and date palms, and from sorghum and grapes among others. However, the two main commercial sources of sugar are sugar cane, a giant bamboo-like grass, in tropical regions and sugar beet, a root vegetables, in temperate regions. The term ‘sugar’, in the singular, usually denotes can sugar or beet sugar, the scientific name for which is sucrose (or saccharose). If consists of a molecule of glucose combined with a molecule of fructose. In the plural, ‘sugars’ denotes the class of soluble simple carbohydrates to which sucrose belongs. Other simple sugars include glucose (or dextrose), which occurs naturally in fruit and vegetables; glucose syrup (partially hydrolysed starch); fructose (or levulose), which is the sugar of fruit and honey; and galactose, found in dairy products. The different sugars vary in sweetening powder. Fructose is sweeter than sucrose and its ‘sweetening power’ in culinary use is greater. Glucose and frutose and therefore sweeter then pure sucrose. • History A few thousand years ago, sugar was already being used in Asia, in the form of cane syrup, whereas in Europe at that time honey and fruit were the only source of sweetening. According to legend, the Chinese and Indians have always known how to manufacture granulated sugar. In about 510 BC, at the time of the expedition of Darius to the valley of the Indus, the Persian discovered a ‘reed which yields honey without the assistance of bees’. They brought it back with them and jealousy guarded the secret of how this sugary substance could be obtained, and traded it as a rarity. In the 4th century Bc, Alexander the Great also brought back the ‘sweet reed’, from which was extracted Carkara (a sanskirt word meaning ‘grain’), a crystal obtained from the juice of the plant. Cultivation of this reed gradually extended to the Mediterranean basin (Venice an important trade centre for sugar) and to Africa. A new food had just been created: saccbarose for the Greeks, saccharum for the Romans, sukkar for the Arabs, then zucchero in venice, cucre (then sucre) in France, sugar in England, azucar in Spain, Zucker in Germany. In the 15th century, the Spanish and Portuguese produced cultivation of the cane into their Atlantic possessions (the Canary Islands, Madeira and Cape Verde islands),so as to free themselves from the monopoly of the Mediterranean producers, Lisbon soon superseded Vinece as the principal European city of refining. The discovery of the New World and other colonial conquests led to the extension of sugar-cane cultivation, firstly in the Carrebbean, Brazil and Mexico, next in the Islands of the Indian Ocean, then in Indonesia, and finally as far as the Philippines and Oceania. The West Indies, which had become known as the “Sugar Islands’, provided sugar for the refineries of the European ports. Growing European demand for sugars, later increased even more by the fashion for tea, coffee and chocolate, was a major reason for the slave trade, which kept the American sugar plantations supplied with labour. Sugar beet remained initially unexploited, although French botanist Oliver de Serres had drawn attention to its high sugar content as early as 1575. It was not until 1747 that the German chemist Marggaaf succeeded in extracting sugar from beer and solidifying it. In 1786, a former student of his called Achard tried to produce it on an industrial basis, but the output was still small, with a very high cost. In 1800, chaptal published some conclusive fingins and blockades of France during the Napoleonic Wars cut off continental Europe from supplies of cane sugar and gave an additional impetus. In 1811, Delesssert perfected the industrial extraction of beet sugar in his Passy refinery ; on 2 January 18112, he offered Napoleon I the first sugar loaf, France later became the first large-scale beet sugar producer in Europe. Today, sugar beet is grown extensively in Russia the Ukraine, Germany, France, Poland and northwestern USA. Sugar cane is grown in Brazil, India, China, the southern states of the USA, Thailand, Australia, Mexico, Southern Africa and Pakistan. • Manufacture of raw sugar. Once harvested, the beets and cane must be converted there is no microbiological degradation and no loss of their rich sugar content. For this reason, raw sugar factories are established close to the growing areas and work without a break during the whole harvesting campaign, which lasts several months. The principle of raw sugar production from both beet and can consists of extracting the sucrose by successively eliminating the other constituent parts of the plant. The root of the beet is sliced and the sweet juice is extracted by diffusion in hot water. The juice, which contains 13-15% sugar, is then treated with milk of lime and carbon dioxide. This results in the production of chalk trapping much of the insoluble non-sugar material, which is filtered off to give a clear juice. In the case of cane sugar, the cut cane is shredded, crushed and sprayed with hot water. The juice is heated, treated with lime and then filtered. Both clarified can and beer juices are then concentrated by evaporation under reduced pressure until crystallization is induced. The concentrated crystallized mass is transferred to mixers (crystallizers), where crystal grow continues. The crystalline raw sugar is then separated from the remaining syrup by centrifugation. Not all of the sugar may have been extracted from the juice at this stage, so the remaining liquid may be recycled. When it is no longer economically practical to extract more sugar, the remaining syrupy liquid is called molasses. Cane molasses is called blackstrap and has various uses in food and drink processing, beet molasses is unfit for human consumption and is used in animal feed. Some raw can sugars are prepared with extra care and to recognized standards; these sugars re marketed for consumption as unrefined brown sugars and included such sugars as raw cane demerara and muscovado sugars. In the main, however, raw sugars require further refining. Raw sugar is a stable product, which may be handled, stored and transported to whenever it is to be refined. Unlike the production of raw sugar, refining may continue all years and need not be in the country of origin. cane refineries tend to be in the importing country, while raw beer is often refined adjacent to the raw beet sugar factory. • Refining raw can sugar Refining raw cane sugar removes all impurities, leaving an end-product of pure natural sucrose. This product contains no artificial colouring, preservation or flavourings of any kind. White refined sugar contains 99.9% pure sucrose; brown sugar contain a small proportion of molasses, which imparts colour and flavour. The raw sugar consists of brown sugar crystals containing many impurities and covered with a coating of molasses. The outer layers are first softened with a warm syrup solution to create a butter-like mixture called magna. This is passed into centrifugal machines to separate the molasses film from the crystals. The crystals are rewashed to remove remaining impurities and treated again with lime and carbon dioxide. The emerging liquid, which is a clear amber colour, is passed over hone charcoal or another decolorizing agent (such as resin) to remove nearly all the soluble impurities and any nonsweetening colouring matter. The liquid is now colourless and clear and ready for recrystallization. The liquid is boiled in a vacuum to avoid colouring or destroying the sugar by heat. When the liquid reaches the correct consistency, crystallization is started by adding to the liquid a controlled quantity of very small crystals known as ‘seeds’, when the tiny crystals have grown to the required size, they are separated from the mother liquid in centrifugal machines are dried in granulators. The boiling and crystallization process is repeated several times. Before the sugar starts to discolour. This liquid is then used to make other sugar products, such as golden syrup, or is boiled and crystallized again together with syrup separated from the raw sugar magna. The final syrup is called ‘refinery molasses’. Different sizes of sugar crystals are normally produced by variations in boiling technique and duration. The crystals are graded by screening before being packed just under half the sugar produced is used in direct form; the remainder is sold to food industries or to specialists producing items containing sugar. Sugars and sugar products. White sugar is refined beet or cane sugar containing 99.9% sucrose and less than 0.06% moisture, having been oven-dried at 1055°C(221°F). it has the highest purity and may be sold as granulated, caster (superfine), grain or lump sugars. Brownsugar is unrefined, or raw, cane sugar (no brown sugar is made from beet because of the inedible molasses), containing 85-98%, sucrose and certain impurities, which account for the varying shades of brown. Natural brown sugar possess a distinctive flavour. There are various types ranging from the very dark most, soft molasses sugar and muscovado, through a pale muscovado to the large crystallizd demetara. Some essential minierals and vitamins may be present but probably in insufficient quantities to substantiate claims that brown sugar is nutritionally superior to white. Some commercial brown sugar are, in fact, refined white sugar with caramel or molasses added to colour and flavour them. This is indicated on the label under ‘ingredients; the natural raw product will have no such list. Organic sugars are those made from organically grown sugar beet and sugar can.
Posted on: Fri, 26 Dec 2014 23:56:00 +0000
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