Sugar

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Magnification of typical table sugar

The term sugar is commonly used to refer to sucrose or table sugar. Technically, however, the term sugar refers to the simple, water-soluble carbohydrates known as monosaccharides, disaccharides, and trisaccharides. Sucrose is a disaccharide.

Along with proteins and fats, carbohydrates are a fundamental component needed by living organisms, providing energy for plants, animals, and microorganisms. For human beings, sucrose or table sugar also addresses an internal aspect, that of the joy of taste, and it is utilized in many foods, such as desserts, and when consuming tea and coffee. However, consumption of excessive amounts of sucrose also correlates with obesity, diabetes mellitus, heart disease, and other diseases, and thus discipline is required in its consumption.

Overall, carbohydrates are a class of biological molecules that contain primarily carbon (C) atoms flanked by hydrogen (H) atoms and hydroxyl (OH) groups (H-C-OH). Carbohydrates are classified according to the number of units of simple sugar they contain. Monosaccharides, or "simple sugars" are monomers, and include such sugars as fructose, glucose, galactose, and ribose. Disaccharides consist of two monosaccharides linked together by covalent bonds, and include such examples as lactose and maltose, in addition to sucrose. Trisaccharides consist of three monosaccharides linked together. The term oligosaccharide refers to carbohydrates that have from 3 to 20 monosaccarides links, and thus includes trisaccharides. Polysaccharides are larger polymers, which may contain hundreds or thousands of monosaccharides. Starch, glycogen, and cellulose are polysaccharides.

Sucrose, the most common meaning of the word sugar, is a white, crystalline, solid disaccharide commonly added to foods in order to promote sweetness, as well as alter physical properties such as preservation and texture. Commercially-produced table sugar comes either from sugarcane (or sugar cane) or from sugar beet, and has tremendous social implications. Among these are its historical relationship with slavery; today's world trade and relationships with international producers; and its relevance to major health concerns.

This article will largely focus on sucrose. The article on carbohydrate provides an overview of other types of sugars, oligosaccharides, and polysaccharides.

Contents

Chemistry

Sucrose is a disaccharide composed of one glucose molecule (left) and one fructose molecule (right)

Monosaccharides, disaccharides, trisaccharides, and oligosaccharides contain one, two, three, four or more monosaccharide units respectively. The general chemical formula for carbohydrates, C(H2O), gives the relative proportions of carbon, hydrogen, and oxygen in a monosaccharide (the proportion of these atoms are 1:2:1). The reactive components of sugars are the hydroxyl groups (-OH), and the aldehyde (-CHO) or ketone groups (C=O), which contain carbon-oxygen double bonds. In disaccharides, oligosaccharides, and polysaccharides, the molar proportions deviate slightly from the general formula because two hydrogens and one oxygen are lost during each of the condensation reactions that forms them. These carbohydrates have the more general formula Cn(H2O)m.

Monosaccharides have the chemical formula C6(H2O)6, with oxygen and hydrogen atoms that differ in position in each sugar molecule. These "simple sugars," glucose, fructose, and galactose, are the building blocks of more complex sugars. For example, sucrose is a disaccharide, a composition of the two monosaccharides glucose and fructose. Likewise, lactose (milk sugar) is made from glucose and galactose, and maltose is made from two molecules of glucose. Disaccharides have the formula C12H22O11.

Sugars may also be classified by the number of carbons they contain. Pentoses are sugar molecules composed of five carbon atoms and include ribose, a component of several chemicals such as NADH and ATP that are important to the metabolic process. Hexoses (six-carbon sugars) include glucose which is a universal substrate for the production of energy in the form of ATP in the process of glycolysis.

Natural origins of sugars

Fructose occurs naturally in many fruits, honey, and some root vegetables, such as sweet potatoes, parsnips, and onions. Lactose is the sugar found naturally in milk. Glucose is produced by plants during photosynthesis and can be stored as sucrose in sugar cane and beets.

Disaccharides such as maltose, produced in the germination of cereals such as barley, and sucrose are more commonly extracted and added to foods, rather than eaten in their original form.

Sucrose, best known in the form of table sugar, is derived from plant sources. The most important two sugar crops are sugarcane and sugar beets, in which sugar can account for between 12 and 20 percent of the plant's dry weight. Some lesser commercial sugar crops include the date palm, sorghum, and sugar maple.

Production of table sugar from sugarcane and sugar beet

Sugarcane plant

Sugarcane or Sugar cane (Saccharum) is a genus of six to 37 species (depending on taxonomic interpretation) of tall grasses (family Poaceae, tribe Andropogoneae), native to warm temperate to tropical regions of the Old World, and also common now in the New World, such as Brazil and the Caribbean Islands. They have stout, jointed fibrous stalks two to six meters tall and sap rich in sugar. All the species interbreed, and the major commercial cultivars are complex hybrids.

Sugar beet (Beta vulgaris) is a plant whose root also contains a high concentration of sucrose and is grown commercially for sugar as well. Beet sugar comes from regions with cooler climates: northwest and eastern Europe, northern Japan, plus some areas in the United States, including California. Europe and Ukraine are significant exporters of sugar from sugar beets.

Little perceptible difference exists between sugar produced from beet and that from cane. Tests can distinguish the two, and some tests aim to detect fraudulent abuse of European Union subsidies or to aid in the detection of adulterated fruit juice.

The greatest quantity of sugar is produced in Brazil, Europe, India, China, and the United States (in descending order). In 2005/2006, 147.7 million tons of sugar was estimated to be produced worldwide.

Cane

Stalks of sugar cane ready for processing

Cane-sugar producers crush the harvested vegetable material, then collect and filter the juice. They then treat the liquid (often with lime) to remove impurities and then neutralize it with sulfur dioxide. Next, the juice is boiled during which sediment settles to the bottom and scum rises to the surface, both of which are removed. The heat is then turned off and the liquid crystallizes, usually while being stirred, to produce sugar crystals. It is usual to remove the uncrystallized syrup with a centrifuge. The resultant sugar is then either sold as is for use or processed further to produce lighter grades. This processing may take place in another factory in another country.

Beet

Beet-sugar producers slice the washed beets, extract the sugar with hot water in a "diffuser," and then use an alkaline solution ("milk of lime" and carbon dioxide) to precipitate impurities. After filtration, the juice is concentrated into about 70 percent solids by evaporation, and the sugar is extracted by controlled crystallization. Then the sugar crystals are removed by a centrifuge, and the liquid is recycled during the stages of crystallization. Sieving the resultant white sugar produces different grades for selling. When economic constraints prevent the removal of more sugar, the manufacturer discards the remaining liquid, now known as molasses.

Culinary sugars

Originally a luxury, sugar eventually became sufficiently cheap and common to influence standard cuisine. Britain and the Caribbean islands have cuisines where sugar usage has become particularly prominent.

Sugar forms a prominent element in confectionery and desserts. Cooks use it as a food preservative as well as for sweetening.

Raw sugars comprise yellow to brown sugars made from clarified cane-juice boiled down to a crystalline solid with minimal chemical processing. Raw sugars are produced in the processing of sugar beet juice, but only as intermediates en route to white sugar. Types of raw sugar available as a specialty item outside the tropics include demerara, muscovado, and turbinado. Mauritius and Malawi export significant quantities of such specialty sugars. Raw sugar is sometimes prepared as loaves rather than as a crystalline powder: in this technique, sugar and molasses are poured together into molds and allowed to dry. The resulting sugar cakes or loaves are called jaggery or gur in India, pingbian tong in China, and panela, panocha, pile, and piloncillo in various parts of Latin America.

Mill white sugar, also called plantation white, crystal sugar, or superior sugar, consists of raw sugar in which the production process does not remove colored impurities, but rather bleaches them white by exposure to sulfur dioxide. This is the most common form of sugar in sugarcane growing areas, but does not store or ship well; after a few weeks, its impurities tend to promote discoloration and clumping.

Brown sugars derive from the late stages of sugar refining, when sugar forms fine crystals with significant molasses-content, or by coating white refined sugar with a cane molasses syrup. Their color and taste become stronger with increasing molasses-content, as do their moisture-retaining properties. Brown sugars also tend to harden if exposed to the atmosphere, although proper handling can reverse this.

Blanco directo, a white sugar common in India and other south Asian countries, comes from precipitating many impurities out of the cane juice by using phosphatation—a treatment with phosphoric acid and calcium hydroxide similar to the carbonatation technique used in beet-sugar refining. In terms of sucrose purity, blanco directo is more pure than mill white, but less pure than white refined sugar.

White refined sugar has become the most common form of sugar in North America as well as in Europe. Refined sugar can be made by dissolving raw sugar and purifying it with a phosphoric acid method similar to that used for blanco directo, a carbonatation process involving calcium hydroxide and carbon dioxide, or by various filtration strategies. It is then further decolorized by filtration through a bed of activated carbon or bone char depending on where the processing takes place. Beet sugar refineries produce refined white sugar directly without an intermediate raw stage. White refined sugar is typically sold as granulated sugar, which has been dried to prevent clumping. Granulated sugar may also be found in the form of powdered sugar, confectioners' sugar, icing sugar, superfine sugar, and sugar cubes, all which vary in crystal sizes.

History

Sugarcane, a tropical grass, probably originated in New Guinea. In the course of prehistory, its prominence spread throughout the Pacific Islands, India, and by 200 B.C.E., it was being grown in China as well.

Originally, people chewed the cane raw to extract its sweetness. Early refining methods, first developed by inhabitants of India in 500 B.C.E., involved grinding or pounding the cane in order to extract the juice, and then boiling down the juice or drying it in the sun to yield sugary solids that resembled gravel. Understandably, the Sanskrit word for "sugar" (sharkara), also means "gravel." Similarly, the Chinese use the term "gravel sugar" (Traditional Chinese: 砂糖) for table sugar.

In 510 B.C.E., soldiers of Darius the Great near the Indus River discovered "reeds which produce honey without bees." The plants remained exotic in Europe until the arrival of the Arabs who started cultivating them in Sicily and Spain. Only after the Crusades, whose soldiers returned with what they perceived to be "sweet salt," did sugar begin to rival honey as the sweetener in Europe. While sugar cane would not grow in northern Europe, sugar could be extracted from certain beets and these began to be widely cultivated around 1801, after the British control of the seas during the Napoleonic wars isolated mainland Europe from the Caribbean.

The history of sugar in the West

The 1390s saw the development of a better press, which doubled the juice obtained from sugar cane. This permitted economic expansion of sugar plantations to Andalusia and the Algarve. In the 1420s, sugar was carried to the Canary Islands, Madeira and the Azores.

In 1493, Christopher Columbus stopped at La Gomera in the Canary Islands, for wine and water, intending to stay only four days. However, he stayed a month. When he finally sailed, leaving for the New World, the governor, Beatrice de Bobadilla, gave him cuttings of sugarcane, which became the first to reach the Americas.

The Portuguese began sugar production in Brazil. Hans Staden writes in his account of the New World, published in 1533, that by 1540 Santa Catalina Island had eight hundred sugar-mills and the north coast of Brazil, Demarara and Surinam had another two thousand. Approximately three thousand small mills built before 1550 in the New World created an unprecedented demand for cast iron, gears, levers, axles and other implements. Specialist trades in mold making and iron casting were inevitably created in Europe by the expansion of sugar. Sugar mill construction is the missing link of the technological skills needed for the Industrial Revolution that is now recognized as having begun in the first part of the 1600s.

After 1625, the Dutch carried sugarcane from South America to the Caribbean islands—from Barbados to the Virgin Islands. In the years 1625 to 1750, sugar was worth its weight in gold. Prices declined slowly as production became multi-sourced, especially through British colonial policy. Sugar production also increased in the American colonies, Cuba, and Brazil. African slaves, who had increased resistance to the diseases of malaria and yellow fever, became the dominant plantation worker, while European indentured servants were in shorter supply, susceptible to disease, and a less economic investment. Local Native American populations had been reduced by European diseases like smallpox.

With the European colonization of the Americas, the Caribbean became the world's largest source of sugar. These islands could grow sugarcane using slave labor at vastly lower prices than cane sugar imported from the East. Thus the economies of entire islands such as Guadaloupe and Barbados became based on sugar production. The largest sugar producer in the world, by 1750, was the French colony known as Saint-Domingue, today the independent country of Haiti. Jamaica was another major producer in the 1700s.

During the eighteenth century, sugar became enormously popular and went through a series of booms. The heightened demand and production of sugar came about to a large extent due to a great change in the eating habits of many Europeans; they began consuming jams, candy, tea, coffee, cocoa, processed foods, and other sweet victuals in much greater numbers. Reacting to this increasing craze, the islands took advantage of the situation and began harvesting sugar in extreme amounts. In fact, they produced up to 90 percent of the sugar that the western Europeans consumed. Of course some islands were more successful than others when it came to producing the product. The production of sugar in Barbados and the British Leewards accounted for 93 percent and 97 percent respectively of each island’s exports.

Planters later began developing ways to boost production even more. For example, they began using more animal manure when growing their crops. They also developed more advanced mills and began using better types of sugarcane. Despite these and other improvements, the prices of sugar reached soaring heights, especially during events such as the revolt against the Dutch and during the Napoleonic wars. Sugar remained in high demand, and the islands' planters took advantage of the situation.

As Europeans established sugar plantations on the larger Caribbean islands, prices fell, especially in Britain. The previous luxury product began, by the eighteenth century, to be commonly consumed by all levels of society. At first, most sugar in Britain was used in tea, but later candies and chocolates became extremely popular. Sugar was commonly sold in solid cones and required a sugar nip, a pliers-like tool, to break off pieces.

Sugarcane quickly exhausts the soil, and growers pressed larger islands with fresher soil into production in the nineteenth century. For example, it was in this century that Cuba rose as the richest land in the Caribbean (with sugar being its dominant crop) because it was the only major island that was free of mountainous terrain. Instead, nearly three-quarters of its land formed a rolling plain which was ideal for planting crops. Cuba also prospered above other islands because they used better methods when harvesting the sugar crops. They had been introduced to modern milling methods such as water mills, enclosed furnaces, steam engines, and vacuum pans. All these things increased their production and production rate.

After the Haitian Revolution established the independent state of Haiti, sugar production in that country declined and Cuba replaced Saint-Domingue as the world's largest producer.

Long established in Brazil, sugar production spread to other parts of South America, as well as to newer European colonies in Africa and in the Pacific.

The rise of the beet

In 1747, German chemist Andreas Marggraf identified sucrose in beet root. This discovery remained a mere curiosity for some time, but eventually his student Franz Achard built a sugar beet processing factory at Cunern in Silesia, under the patronage of Frederick William III of Prussia (reigned 1797–1840). While never profitable, this plant operated from 1801 until it was destroyed during the Napoleonic Wars (c. 1802–1815).

Napoleon, cut off from Caribbean imports by a British blockade and at any rate not wanting to fund British merchants, banned sugar imports in 1813. The beet-sugar industry that emerged in consequence grew, and today, sugar-beet provides approximately 30 percent of world sugar production.

Slavery conditions on sugar plantations

Millions of slaves crossed the Atlantic Ocean to cultivate and harvest sugar on plantations in Brazil and the Caribbean. Between 1701 and 1810, nearly one million slaves were brought to work in Jamaica and Barbados for this very reason.

In the Caribbean, the death rates for black slaves were higher than birth rates; in Jamaica three percent of the population died each year, and four percent in the smaller islands. The main causes for this were overwork and malnutrition. Slaves worked from sun-up until sun-down in the tropical heat and were supervised under demanding masters, with little medical care. Slaves also had poor living conditions and consequently they contracted many diseases.

The lower birth rate also may be due to the fact that females simply did not want to bring new life into their harsh world, a thought author Jan Rogozinski briefly mentions in his book, A Brief History of the Caribbean. He states, "Perhaps slave mothers simply did not see much point in raising children solely to provide laborers for their masters."

Much of this unarguably unjust social practice came to an end with Great Britain's abolishment of slavery in the early 1830s, after abolishing the trade itself in 1807.

Sugar today

Cuba was a large producer of sugar in the twentieth century until the collapse of the Soviet Union took away their export market and the industry collapsed.

In developed countries, the sugar industry relies on machinery, with a low requirement for manpower. A large beet-refinery producing around 1,500 tons of sugar per day needs a permanent workforce of about 150 for 24-hour production. Sugar beets provide approximately 30 percent of world sugar production.

While no longer grown by slaves, sugar from developing countries has an on-going association with workers earning minimal wages and living in extreme poverty. Some argue that the current world trade scene creates a modern day form of slavery in which international trade agreements and regulations may undermine farmers' economic prosperity in many countries.

Health concerns

Argument continues as to the value of extrinsic sugar (sugar added to food) compared to that of intrinsic sugar (sugar, seldom sucrose, naturally present in food). Adding sugar to food particularly enhances taste, but has the primary drawback of increasing caloric content, and when consumed in excess, may promote the onset of disease and other health concerns.

While the traditional concerns of sugar consumption have been tooth decay and hyperactivity, excessive sugar intake has also been related to increased trends of obesity, and endangers those suffering from diabetes mellitus.

In 2003, four United Nations agencies, the World Health Organization (WHO) and the Food and Agriculture Organization (FAO), commissioned a report compiled by a panel of 30 international experts. It stated that the total of free sugars (all monosaccharides and disaccharides added to foods by the manufacturer, cook or consumer, plus sugars naturally present in honey, syrups and fruit juices) should not account for more than ten percent of the energy intake of a healthy diet, while carbohydrates in total should represent between 55-75 percent of the energy intake (WHO 2003). However, the Center for Science in the Public Interest states that the typical American eats 16 percent of his or her calories from added sugar. Moreover, the USDA found that Americans eat about 20 teaspoons of sugar a day, double the recommended amount, and that sugar consumption is increasing and has been increasing almost every year since 1982.

Type II diabetes

Type II diabetes is one of the greatest health concerns in relation to the consumption of sugar, especially sucrose, which is commonly eaten in excess. When sugar is consumed, blood glucose levels rise and are mediated by the body's endogenous production of insulin, a hormone that incorporates glucose from the blood into cells. However, in Type II diabetes, little or no insulin may be produced or insulin may become resistant. When one eats carbohydrate foods, the cells of the body cannot obtain glucose and become deprived of energy. Over time, excessive glucose in the blood may begin to damage some organs such as the eyes or kidneys.

Therefore, consumption of sugar must be carefully monitored in order to preserve one's state of health. As obesity promotes the onset of this acquired form of diabetes, exercise is another vital tool as well. Eating low glycemic index foods, which do not spike blood glucose levels as dramatically as those foods that rank high on the index, may also be important.

Hyperactivity

Many individuals believe that eating too much sugar (not only sucrose, but also other varieties such as fructose) will cause some children to become hyperactive giving rise to the term "sugar high" or "sugar buzz" used in the United States. Recent studies have not shown a link between the consumption of sugar and hyperactivity levels,[1] even when the researchers focused on children with a presumed "sugar-sensitivity." These experiments were not done in the context of a control group following a base diet level matching the sugar intake recommendation of the WHO/FAO; therefore they are not conclusive. They do suggest, however, that increased levels of sugar intake, above the high level consumed in a standard diet, may have no impact on levels of hyperactivity that may or may not already be present.

Sugar economics

Sugar may be consumed in the producing country, under government regulation and pricing, or distributed abroad under long-term trade agreements. Sugar without trade agreements is sold freely to various nations, companies, or individual buyers. Thus, sugar is traded in a "residual" market, in which free trade sugar accounts for only a portion (usually 20-25 percent) of all sugar produced worldwide. As this fraction may be small, any change in total consumption or production may produce a large change in the supply of free trade sugar. The resultant sensitive balance of supply and demand accounts for the historic trend of constantly fluctuating sugar prices.

Sugar trade policy has several international and domestic economic effects. In many industrialized countries, sugar has become one of the most heavily subsidized agricultural products. The European Union, the United States, and Japan all maintain elevated price-floors for sugar through subsidizing domestic production and imposing high tariffs on imports. These subsidies and high import tariffs make it difficult for other countries to export to such groups as the EU states, or compete with them on world markets. Likewise, the U.S. sets high sugar prices to support its producers with the effect that many beverage manufacturers have switched to the much cheaper and abundant corn syrup, and many candy manufacturers have moved out of the country altogether.

Within international trade bodies, especially in the World Trade Organization, the "G20" countries led by Brazil have argued that because these sugar markets essentially exclude their cane-sugar exports, they receive lower prices than they would under free trade. While both the European Union and United States maintain trade agreements whereby certain developing and less-developed countries can sell certain quantities of sugar into their markets, free of the usual import tariffs, countries outside these preferred trade regimes have complained that these arrangements violate the "most favored nation" principle of international trade.

Therefore, the principles of progressive world trade may be difficult with varying interests and economic motivations among Western States and Third World countries alike. Nonetheless, developed world governments have made some attempts to aid less financially sound nations in the sugar trade. For instance, in a humanitarian effort and attempt to appease free market determinations, small quantities of sugar, especially specialty grades of sugar, reach the market as 'fair trade' commodities. This fair-trade system produces and sells these products with the understanding that a larger-than-usual fraction of the revenue will support small farmers in the developing world. Some argue that more could be done to stabilize mutual economic prosperity worldwide.

References

  • Hannah, A. C., and D. Spense. 1996. The International Sugar Trade. Cambridge: Woodhead Publishing Limited. ISBN 1855730693
  • Rogozinsky, J. 1999. A Brief History of the Caribbean. New York: Penguin Putnam. ISBN 0452281938
  • World Health Organization (WHO). 2003. WHO Technical Report, Series 916, Diet, Nutrition, and the Prevention of Chronic Diseases.

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