Sugar
This article deals with sugar as food and as an important and widely-traded commodity. For other uses see sugar (disambiguation).
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Magnified crystals of refined sugar |
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Magnification of typical sugar |
In general use, non-scientists take "sugar" to mean
sucrose, also called "table sugar" or saccharose, a white
crystalline
solid disaccharide. Humans most commonly use sucrose as their sugar of choice for altering the
flavor and properties (such as
mouthfeel, preservation, and texture) of
beverages and food. Commercially-produced table sugar comes either from
sugar cane or from
sugar beet.
The "simple" sugars, or monosaccharides (such as
glucose), store
energy which
biological cells use and consume. In a list of ingredients, any word that ends with "ose" probably denotes a sugar.
For information on the other sugars, see
monosaccharide and
disaccharide.
In culinary terms,
sugar as a type of
food delivers one of the
primary taste sensations, that of
sweetness.
The English word "sugar" ultimately originates from the
Sanskrit word
sharkara or
śarkarā (शर्करा) which means "sugar" or "pebble". It probably came to English by way of the French, Spanish and/or Italians who derived their word for sugar from the Arabic
al sukkar (whence the Spanish word
azúcar, the Old Italian word
zucchero, the Old French word
zuchre). The Arabs in turn derived their word from the Persian
shakar, derived from the original Sanskrit.
The first production of sugar from sugar-cane took place in
India.
Alexander the Great's companions reported seeing "
honey produced without the intervention of bees" and it remained exotic in Europe until the Arabs started cultivating it in Sicily and Spain. Only after the Crusades did it begin to rival honey as the sweetener in Europe. The Spanish began cultivating sugar cane in the West Indies in 1506, and in Cuba in 1523. It was first cultivated in Brazil 1532 by the Portuguese.
Table sugar or sucrose comes from plant sources. The most important two sugar crops are
sugarcane (
Saccharum spp.) and
sugar beets (
Beta vulgaris), in which sugar can account for 12%–20% of the plant's dry weight. Some minor commercial sugar crops include the
date palm (
Phoenix dactylifera),
sorghum (
Sorghum vulgare), and the
sugar maple (
Acer saccharum). In the
financial year 2001/
2002, 134.1 million
tonnes of sugar were produced worldwide.
Most cane sugar comes from countries with warm climates, such as
Brazil, India,
China and
Australia (in descending order). In 2001/2002 there was over twice as much sugar produced in
developing countries as in developed countries. The greatest quantity of sugar is produced in
Latin America, the
United States and the
Caribbean nations, and in the
Far East.
Beet sugar comes from regions with cooler climates: north- west and eastern Europe, northern Japan, plus some areas in the United States including California. The beet growing season ends with the start of harvesting around September. Harvesting and processing continues until March in some cases. The duration of harvesting and processing is influenced by the availability of processing plant capacity, and weather - harvested beet can be laid up until processed but frost damaged beet becomes effectively unprocessable.
The
European Union (EU) has become the world's second-largest sugar exporter. The Common Agricultural Policy of the EU sets maximum quotas for members' production to match supply and demand, and a price. Excess production quota is exported (approx 5 million tonnes in
2003). Part of this is "quota" sugar which is subsidised from industry levies, the remainder (approx half) is "C quota" sugar which is sold at market price without subsidy. These
subsidies and a high import
tariff make it difficult for other countries to export to the EU states, or compete with it on world markets. The U.S. sets high sugar prices to support its producers with the effect that many sugar consumers have switched to
corn syrup (beverage manufacturers) or moved out of the country (candy makers).
The cheap prices of glucose syrups produced from wheat and corn (maize) threaten the traditional sugar market. In combination with artificial sweeteners, drink manufacturers can produce very low-cost products.
Cane
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, this is then neutralized with
sulfur dioxide. The juice is then boiled, the sediment settles to the bottom and can be dredged out, scum rises to the surface and this is skimmed off. The heat is removed and the liquid crystallises, usually while being stirred, to produce sugar crystals. It is usual to remove the uncrystallised 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, then extract the sugar with hot water in a 'diffuser'. An alkaline solution ("
milk of lime" and
carbon dioxide from the lime kiln) then serve to
precipitate impurities, see
carbonatation. After filtration the juice is concentrated by evaporation to a content of about 70% solids. The sugar is extracted by controlled crystallisation. The sugar crystals are removed by a centrifuge and the liquid recycled in the crystalliser stages. When economic constraints prevent the removal of more sugar, the manufacturer discards the remaining liquid, now known as
molasses.
Sieving the resultant white sugar produces different grades for selling.
Cane versus beet
Little perceptible difference exists between sugar produced from beet and that from cane. Tests can distinguish the two, and some tests have developed in order to reduce fraudulent abuse of EU subsidies, and also to aid in the detection of adulterated
fruit-juice.
The production of sugar results in residues which differ substantially depending on the raw materials used and on the place of production. While cooks often use cane molasses in food, molasses from sugar beet often becomes a spread for sandwiches and pancakes, industrial
fermentation feedstock, or animal feed. Once dried, either type of molasses can serve as fuel for burning.
Culinary sugars
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 where 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.
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 comes in various crystal sizes " for home and industrial use " depending on the application:
* Coarse-grained sugars, such as
sanding sugar (
nibbed sugar or
sugar nibs) find favor for decorating
cookies (biscuits) and other desserts.
* Normal granulated for table use typically has a grain size about 0.5 mm across
* Finer grades result from selectively sieving the granulated sugar
**
caster sugar (0.35 mm), commonly used in baking
**
superfine sugar, also called
baker's sugar,
berry sugar, or
bar sugar " favored for sweetening drinks or for preparing
meringue * Finest grades
**
Powdered sugar,
10X sugar, confectioner's sugar (0.060 mm), or
icing sugar (0.024 mm), produced by grinding sugar to a fine powder. The manufacturer may add a small amount of
anti-caking agent to prevent clumping " either
cornstarch (1% to 3%) or tri-
calcium phosphate.
Retailers also sell sugar cubes or lumps for convenient consumption of a standardised amount.
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.
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Sucrose, a disaccharide of glucose (left); and fructose, important molecules in the body. |
Biochemists regard sugars as relatively simple
carbohydrates. Sugars include
monosaccharides,
disaccharides, trisaccharides and the oligosaccharides - containing 1, 2, 3, and 4 or more monosaccharide units respectively. Sugars contain either
aldehyde groups (-CHO) or
ketone groups (C=O), where there are carbon-oxygen double bonds, making the sugars reactive. Most sugars conform to (CH
2O)
n where n is between 3 and 7. A notable exception is
deoxyribose, which as the name suggests is "missing" an oxygen. As well as being classified by their reactive group, sugars are also classified by the number of carbons they contain. Derivatives of trioses (C
3H
6O
3) are intermediates in
glycolysis. Pentoses ( 5 carbon sugars) include
ribose and deoxyribose, which are present in
nucleic acids. Ribose is also a component of several chemicals that are important to the metabolic process, including
NADH and
ATP. Hexoses (6 carbon sugars) include glucose which is a universal substrate for the production of energy in the form of ATP. Through
photosynthesis plants produce glucose which is then converted for storage as an energy reserve in the form of other carbohydrates such as
starch, or as in cane and beet as sucrose.
Many pentoses and hexoses can form
ring structures. In these closed-chain forms, the aldehyde or ketone group is not free, so many of the reactions typical of these groups cannot occur. Glucose in solution exists mostly in the ring form at
equilibrium, with less than 0.1% of the molecules in the open-chain form.
Monosaccharides in a closed-chain form can form
glycosidic bonds with other monosaccharides, creating disaccharides (such as sucrose) and polysaccharides (such as
starch).
Enzymes must
hydrolyse or otherwise break these glycosidic bonds before such compounds can be used in
metabolism. After digestion and absorption the principal monosaccharides present in the blood and internal tissues are: glucose, fructose, and galactose.
The prefix "glyco-" indicates the presence of a sugar in an otherwise non-carbohydrate substance. Note for example
glycoproteins, proteins to which one or more sugars are connected.
Simple sugars include
sucrose,
fructose,
glucose,
galactose,
maltose,
lactose and
mannose. Disaccharides occur most commonly as sucrose (cane or beet sugar - made from one glucose and one fructose), lactose (milk sugar - made from one glucose and one galactose) and maltose (made of two glucoses). These disaccharides have the formula C
12H
22O
11.
Hydrolysis can convert sucrose into a syrup of fructose and glucose, producing
invert sugar. This resulting syrup is sweeter than the original sucrose, and is useful for making confections because it does not crystalize as easily and thus produces a smoother finished product.
Inhabitants of India developed the process of making sugar by evaporating cane juice about 500 BC.
Sugarcane, a tropical grass, probably originated in
New Guinea. In the course of prehistory, its culture spread throughout the
Pacific Islands and into India. By 200 B.C., it was being grown in China as well. Westerners discovered sugarcane in the course of military expeditions into India.
Nearchos, one of Alexander the Great's commanders, described it as "a reed that gives honey without bees."
Originally, people chewed the cane raw to extract its sweetness. Sugar refining developed in the
Middle East, India and China, where sugar became a staple of cooking and
desserts. Early refining methods 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. 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 later times sugar spread to other areas of the world through trade. It came to Europe with the arrival of the
Moors.
Crusaders also brought sugar home with them after their campaigns in the
Holy Land, as there they encountered caravans carrying "sweet salt". 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 Arabs and Berbers introduced sugar to Western Europe when they conquered the Iberian peninsula in the 8th century AD. The 1390s saw the development of a better press, which doubled the juice obtained from the 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
Gomera in the Canary Islands, for wine and water, intending to stay only four days. He became romantically involved with the Governor of the island, Beatrice de Bobadilla, and stayed a month. When he finally sailed she gave him cuttings of sugarcane, which became the first to reach the New World.
The Portuguese took sugar to
Brazil.
Hans Staden, published in 1555, writes that by 1540
Santa Catalina Island had 800 sugar-mills and the north coast of Brazil, Demarara and
Surinam had another 2000. Approximately 3000 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 recognized as beginning 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 became the dominant plantation worker as they were resistant to the diseases of
malaria and
yellow fever. European
indentured servants were in shorter supply, susceptible to disease and a less economic investment. Local
Native Americans 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 sugar-cane using slave labour 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. For example, 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 ninety 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. For instance, Barbados and the British Leewards can be said to have been the most successful in the production of sugar because it counted for 93% and 97% 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 sugar-cane. Despite these and other improvements, the prices of sugar reached soaring heights, especially during events such as the revolt against the Dutch and the Napoleonic wars. Sugar remained in highly demand, and the islands' planters knew exactly how to take 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.
Sugar-cane 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
Haïtian 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 beet
In 1747 the 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 sugarbeet-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 destroyed during the
Napoleonic Wars (ca 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% 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.
Cuba was a large producer of sugar in the 20th century until the collapse of the
Soviet Union took away their export market and the industry collapsed.
In the developed countries, the sugar industry relies on machinery, with a low requirement for manpower. A large beet-refinery producing around 1,500 tonnes of sugar a day needs a permanent workforce of about 150 for 24-hour production.
Mechanization
Beginning in the late 18th century, sugar production became increasingly mechanized. The
steam engine first powered a sugar mill in
Jamaica in
1768, and soon thereafter, steam replaced direct firing as the source of process heat.
In 1813 the
British chemist
Edward Charles Howard invented a method of refining sugar which involved boiling the cane juice not in an open kettle, but in a closed vessel heated by steam and held under partial vacuum. At reduced pressure, water boils at a lower temperature, and this development both saved fuel and reduced the amount of sugar lost through
caramelization. Further gains in fuel efficiency came from the
multiple-effect evaporator, designed by the
African-American engineer
Norbert Rillieux perhaps as early as the 1820s, although the first working model dates from 1845. This system consisted of a series of vacuum pans, each held at a lower pressure than the previous one. The vapors from each pan were used to heat the next, and little heat wasted. Today, multiple-effect evaporators are employed widely in many industries for evaporating water.
The process of separating the sugar from the molasses also received mechanical attention: David Weston first applied the centrifuge to this task in
Hawaii in 1852.
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.
Whereas rotting teeth once seemed the most prominent health hazard from the use of sugar, first the growth in the usage of
rum (a sugar-cane derivative) and then the predominance of concerns about
diabetes and
obesity gradually came to prominence.
Recently, doctors have come to suspect that sugar could cause
gastrointestinal cancer.
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 sugar should not account for more than 10% of a healthy diet. However, the
Sugar Association of the United States of America insists that other evidence indicates that a quarter of our food and drink intake can safely consist of sugar.
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 boosting
calories.
In the United States, a scientific/health debate has started over the causes of a steep rise in obesity in the general population " and one view posits increased carbohydrate consumption in recent decades as a major
factor.
Sugar and hyperactivity
The general public in the
U.S. commonly believes that eating too much sugar (not only sucrose, but also other varieties such as glucose) will cause some children to become
hyperactive " giving rise to the term "sugar high" or "sugar buzz". Recent
studies have not shown a link between the consumption of sugar and hyperactivity levels, even when the researchers focused on children with a presumed "sugar-sensitivity". If parents and teachers believe in the possibility of a sugar-high, this may cause them to perceive children as more energetic and excited after consumption of sweets and sugary beverages through
observer bias.
Others believe that children and adults show the hyperactive effects of sugar equally. On average Americans eat or drink 5 pounds of sugar a month, drastically higher than
10 years ago due to the fact that sugar is in many foods under many different names.
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.
In recent years, sugar prices in these countries have exceeded prices on the international market by up to three times.
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 (LDCs) 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.
In 2004, the
WTO sided with a group of cane-sugar exporting nations (led by Brazil) and ruled the EU sugar-régime and the accompanying
ACP-EU Sugar Protocol (whereby a group of African, Caribbean, and Pacific countries receive preferential access to the European sugar market) illegal. In response, the European Commission proposed on 22 June 2005 to radically reform the EU sugar regime, cutting prices by 39% and eliminating all EU sugar exports. The African, Caribbean, Pacific and
Least developed country sugar exporters have reacted with dismay to the EU sugar proposals, arguing for a fairer reform of the EU regime which would be pro-development and meaningful towards the achievement of the
Millennium Development Goals.
Small quantities of sugar, especially speciality grades of sugar, reach the market as '
fair trade' commodities; the 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.
*
Biobutanol*
Brown sugar*
Caramel*
Corn syrup*
Fermentation*
Glycomics*
Golden syrup*
Holing cane*
Natural brown sugar*
Stevia, a herb many times sweeter than pure sugar
*
Sugar plantations in the Caribbean*
Sugar substitute*A C Hannah,
The International Sugar Trade, ISBN 1855730693
*William Dufty,
Sugar Blues, ISBN 0446343129
History and culture
*
Plant Cultures: botany, history and uses of sugar cane*
The word "sugar" in more than 300 languages.*
Big Sugar: documentaryFood
*
Cook's Thesaurus: Sugar (www.foodsubs.com)
Health
*
Expert Report on diet and chronic disease (WHO/FAO)
*
Sugar accelerates aging*
Center for Science in the Public Interest sugar-labeling campaignTrade
*
Wide range of information about sugars, from the Canadian Sugar Institute, a non-profit trade association of Canada's refined sugar manufacturers.*
Least Developed Countries sugar site*
African, Caribbean and Pacific sugar exporters*
Sugar Traders Association of the UK*
European Union sugar-régime proposals*
WTO ruling on the EU sugar-régime*
US Sugar Import Program*
Sugar statisticsSugar and hyperactivity
*
"Sugar Buzz, Fiber Know-How" article from WebMD
*
"The Myth of the Sugar Buzz" article from Skepticism.Net
Chemical
