Sugar is the generic name for sweet, soluble carbohydrates, many of which are used in food. There are various types of sugar derived from different sources. Simple sugars are called monosaccharides and include glucose (also known as dextrose), fructose, and galactose. The "table sugar" or "granulated sugar" most customarily used as food is sucrose, a disaccharide of glucose and fructose. Sugar is used in prepared foods (e.g., cookies and cakes) and it is added to some foods and beverages (e.g., coffee and tea). In the body, sucrose is hydrolysed into the simple sugars fructose and glucose. Other disaccharides include maltose from malted grain, and lactose from milk. Longer chains of sugars are called oligosaccharides or polysaccharides. Some other chemical substances, such as glycerol may also have a sweet taste, but are not classified as sugars. Diet food substitutes for sugar, include aspartame and sucralose, a chlorinated derivative of sucrose.
Sugars are found in the tissues of most plants and are present in sugarcane and sugar beet in sufficient concentrations for efficient commercial extraction. The world production of sugar in 2011 was about 168 million tonnes. The average person consumes about 24 kilograms (53 lb) of sugar each year (33.1 kg in developed countries), equivalent to over 260 food calories per person, per day. Since the latter part of the twentieth century, it has been questioned whether a diet high in sugars, especially refined sugars, is good for human health. Over-consumption of sugar has been implicated in the occurrence of obesity, diabetes, cardiovascular disease, dementia, and tooth decay. Numerous studies have been undertaken to try to clarify the position, but with varying results, mainly because of the difficulty of finding populations for use as controls that do not consume or are largely free of any sugar consumption.
The etymology reflects the spread of the commodity. The English word "sugar" ultimately originates from the Sanskrit ?????? (?arkar?), via Arabic ??? (sukkar) as granular or candied sugar, which is cognate with the Greek word, kroke, or "pebble". The contemporary Italian word is zucchero, whereas the Spanish and Portuguese words, azúcar and açúcar, respectively, have kept a trace of the Arabic definite article. The Old French word is zuchre and the contemporary French, sucre. The earliest Greek word attested is ???????? (sákk?aris).
Sugar has been produced in the Indian subcontinent since ancient times. It was not plentiful or cheap in early times and honey was more often used for sweetening in most parts of the world. Originally, people chewed raw sugarcane to extract its sweetness. Sugarcane was a native of tropical South Asia and Southeast Asia. Different species seem to have originated from different locations with Saccharum barberi originating in India and S. edule and S. officinarum coming from New Guinea. One of the earliest historical references to sugarcane is in Chinese manuscripts dating back to 8th century BC that state that the use of sugarcane originated in India.
Sugar was found in Europe by the 1st century CE, but only as an imported medicine, and not as a food. The Greek physician Pedanius Dioscorides in the 1st century CE described sugar in his medical treatise De Materia Medica, and Pliny the Elder, a 1st-century CE Roman, described sugar in his Natural History: "Sugar is made in Arabia as well, but Indian sugar is better. It is a kind of honey found in cane, white as gum, and it crunches between the teeth. It comes in lumps the size of a hazelnut. Sugar is used only for medical purposes."
Sugar remained relatively unimportant until the Indians discovered methods of turning sugarcane juice into granulated crystals that were easier to store and to transport. Crystallized sugar was discovered by the time of the Imperial Guptas, around the 5th century CE. In the local Indian language, these crystals were called khanda (Devanagari: ????, Kha??a), which is the source of the word candy. Indian sailors, who carried clarified butter and sugar as supplies, introduced knowledge of sugar on the various trade routes they travelled. Buddhist monks, as they travelled around, brought sugar crystallization methods to China. During the reign of Harsha (r. 606-647) in North India, Indian envoys in Tang China taught methods of cultivating sugarcane after Emperor Taizong of Tang (r. 626-649) made known his interest in sugar. China then established its first sugarcane plantations in the seventh century. Chinese documents confirm at least two missions to India, initiated in 647 CE, to obtain technology for sugar refining. In South Asia, the Middle East and China, sugar became a staple of cooking and desserts.
Crusaders brought sugar home with them to Europe after their campaigns in the Holy Land, where they encountered caravans carrying "sweet salt". Early in the 12th century, Venice acquired some villages near Tyre and set up estates to produce sugar for export to Europe, where it supplemented honey, which had previously been the only available sweetener. Crusade chronicler William of Tyre, writing in the late 12th century, described sugar as "very necessary for the use and health of mankind". In the 15th century, Venice was the chief sugar refining and distribution centre in Europe.
In August 1492, Christopher Columbus stopped at La 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, Beatriz de Bobadilla y Ossorio, and stayed a month. When he finally sailed, she gave him cuttings of sugarcane, which became the first to reach the New World. The first sugar cane harvest was conducted in Hispaniola in 1501, and many sugar mills had been constructed in Cuba and Jamaica by the 1520s. The Portuguese took sugar cane to Brazil. By 1540, there were 800 cane sugar mills in Santa Catarina Island and another 2,000 on the north coast of Brazil, Demarara, and Surinam.
Sugar was a luxury in Europe until the 18th century, when it became more widely available. It then became popular and by the 19th century, sugar came to be considered a necessity. This evolution of taste and demand for sugar as an essential food ingredient unleashed major economic and social changes. It drove, in part, colonization of tropical islands and nations where labor-intensive sugarcane plantations and sugar manufacturing could thrive. The demand for cheap labor to perform the hard work involved in its cultivation and processing increased the demand for the slave trade from Africa (in particular West Africa). After slavery was abolished, there was high demand for indentured laborers from South Asia (in particular India). Millions of slave and indentured laborers were brought into the Caribbean and the Americas, Indian Ocean colonies, southeast Asia, Pacific Islands, and East Africa and Natal. The modern ethnic mix of many nations that have been settled in the last two centuries has been influenced by the demand for sugar.
Sugar also led to some industrialization of areas where sugar cane was grown. For example, Lieutenant J. Paterson, of the Bengal establishment, persuaded the British Government that sugar cane could be cultivated in British India with many advantages and at less expense than in the West Indies; as a result, sugar factories were established in Bihar in eastern India. During the Napoleonic Wars, sugar beet production increased in continental Europe because of the difficulty of importing sugar when shipping was subject to blockade. By 1880, the sugar beet was the main source of sugar in Europe. It was cultivated in Lincolnshire and other parts of England, although the United Kingdom continued to import the main part of its sugar from its colonies.
Until the late nineteenth century, sugar was purchased in loaves, which had to be cut using implements called sugar nips. In later years, granulated sugar was more usually sold in bags. Sugar cubes were produced in the nineteenth century. The first inventor of a process to make sugar in cube form was the Moravian Jakub Kry?tof Rad, director of a sugar company in Da?ice. He began sugar cube production after being granted a five-year patent for the process on January 23, 1843. Henry Tate of Tate & Lyle was another early manufacturer of sugar cubes at his refineries in Liverpool and London. Tate purchased a patent for sugar cube manufacture from German Eugen Langen, who in 1872 had invented a different method of processing of sugar cubes.
Scientifically, sugar loosely refers to a number of carbohydrates, such as monosaccharides, disaccharides, or oligosaccharides. Monosaccharides are also called "simple sugars," the most important being glucose. Most monosaccharides have a formula that conforms to with n between 3 and 7 (deoxyribose being an exception). Glucose has the molecular formula . The names of typical sugars end with -ose, as in "glucose" and "fructose". Sometimes such words may also refer to any types of carbohydrates soluble in water. The acyclic mono- and disaccharides contain either aldehyde groups or ketone groups. These carbon-oxygen double bonds (C=O) are the reactive centers. All saccharides with more than one ring in their structure result from two or more monosaccharides joined by glycosidic bonds with the resultant loss of a molecule of water per bond.
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 hydrolyze or otherwise break these glycosidic bonds before such compounds become metabolized. After digestion and absorption the principal monosaccharides present in the blood and internal tissues include glucose, fructose, and galactose. Many pentoses and hexoses can form ring structures. In these closed-chain forms, the aldehyde or ketone group remains non-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.
Biopolymers of sugars are common in nature. Through photosynthesis, plants produce glyceraldehyde-3-phosphate (G3P), a phosphated 3-carbon sugar that is used by the cell to make monosaccharides such as glucose or (as in cane and beet) sucrose . Monosaccharides may be further converted into structural polysaccharides such as cellulose and pectin for cell wall construction or into energy reserves in the form of storage polysaccharides such as starch or inulin. Starch, consisting of two different polymers of glucose, is a readily degradable form of chemical energy stored by cells, and can be converted to other types of energy. Another polymer of glucose is cellulose, which is a linear chain composed of several hundred or thousand glucose units. It is used by plants as a structural component in their cell walls. Humans can digest cellulose only to a very limited extent, though ruminants can do so with the help of symbiotic bacteria in their gut.DNA and RNA are built up of the monosaccharides deoxyribose and ribose, respectively. Deoxyribose has the formula and ribose the formula .
Because sugars burn easily when exposed to flame, the handling of sugars risks dust explosion. The 2008 Georgia sugar refinery explosion, which killed 14 people and injured 40, and destroyed most of the refinery, was caused by the ignition of sugar dust. In its culinary use, sugar that is exposed to a heat source causes caramelization to take place. As the process occurs, volatile chemicals such as diacetyl are released, producing the characteristic caramel flavor.
Fructose, galactose, and glucose are all simple sugars, monosaccharides, with the general formula C6H12O6. They have five hydroxyl groups (-OH) and a carbonyl group (C=O) and are cyclic when dissolved in water. They each exist as several isomers with dextro- and laevo-rotatory forms that cause polarized light to diverge to the right or the left.
Lactose, maltose, and sucrose are all compound sugars, disaccharides, with the general formula C12H22O11. They are formed by the combination of two monosaccharide molecules with the exclusion of a molecule of water.
The sugar contents of common fruits and vegetables are presented in Table 1. All data with a unit of g (gram) are based on 100 g of a food item. The fructose/glucose ratio is calculated by dividing the sum of free fructose plus half sucrose by the sum of free glucose plus half sucrose.
as a % of
|Red pepper, sweet||6.0||4.2||2.3||1.9||0.0||1.2||0.0|
|Sugar cane||13 - 18||0.2 - 1.0||0.2 - 1.0||11 - 16||1.0||high|
|Sugar beet||17 - 18||0.1 - 0.5||0.1 - 0.5||16 - 17||1.0||high|
Sugar beet became a major source of sugar in the 19th century when methods for extracting the sugar became available. It is a biennial plant, a cultivated variety of Beta vulgaris in the family Amaranthaceae, the tuberous root of which contains a high proportion of sucrose. It is cultivated as a root crop in temperate regions with adequate rainfall and requires a fertile soil. The crop is harvested mechanically in the autumn and the crown of leaves and excess soil removed. The roots do not deteriorate rapidly and may be left in a clamp in the field for some weeks before being transported to the processing plant. Here the crop is washed and sliced and the sugar extracted by diffusion. Milk of lime is added to the raw juice and carbonatated in a number of stages in order to purify it. Water is evaporated by boiling the syrup under a vacuum. The syrup is then cooled and seeded with sugar crystals. The white sugar that crystallizes out can be separated in a centrifuge and dried. It requires no further refining.
Sugarcane refers to any of several species, or their hybrids, of giant grasses in the genus Saccharum in the family Poaceae. They have been cultivated in tropical climates in South Asia and Southeast Asia since ancient times for the sucrose that is found in their stems. A great expansion in sugarcane production took place in the 18th century with the establishment of slave plantations in the Americas. The use of slavery meant that this was the first time that sugar became cheap enough for most people, who previously had to rely on honey to sweeten foods. It requires a frost-free climate with sufficient rainfall during the growing season to make full use of the plant's great growth potential. The crop is harvested mechanically or by hand, chopped into lengths and conveyed rapidly to the processing plant (commonly known as a sugar mill). Here, it is either milled and the juice extracted with water or extracted by diffusion. The juice is then clarified with lime and heated to destroy enzymes. The resulting thin syrup is concentrated in a series of evaporators, after which further water is removed by evaporation in vacuum containers. The resulting supersaturated solution is seeded with sugar crystals and the sugar crystallizes out and is separated from the fluid and dried. Molasses is a by-product of the process and the fiber from the stems, known as bagasse, is burned to provide energy for the sugar extraction process. The crystals of raw sugar have a sticky brown coating and either can be used as they are or can be bleached by sulfur dioxide or can be treated in a carbonatation process to produce a whiter product. About 2,500 litres (660 US gal) of irrigation water is needed for every one kilogram of sugar produced.
Refined sugar is made from raw sugar that has undergone a refining process to remove the molasses. Raw sugar is sucrose which is extracted from sugarcane or sugar beet. While raw sugar can be consumed, the refining process removes unwanted tastes and results in refined sugar or white sugar.
The sugar may be transported in bulk to the country where it will be used and the refining process often takes place there. The first stage is known as affination and involves immersing the sugar crystals in a concentrated syrup that softens and removes the sticky brown coating without dissolving them. The crystals are then separated from the liquor and dissolved in water. The resulting syrup is treated either by a carbonatation or by a phosphatation process. Both involve the precipitation of a fine solid in the syrup and when this is filtered out, many of the impurities are removed at the same time. Removal of color is achieved by using either a granular activated carbon or an ion-exchange resin. The sugar syrup is concentrated by boiling and then cooled and seeded with sugar crystals, causing the sugar to crystallize out. The liquor is spun off in a centrifuge and the white crystals are dried in hot air and ready to be packaged or used. The surplus liquor is made into refiners' molasses. The International Commission for Uniform Methods of Sugar Analysis sets standards for the measurement of the purity of refined sugar, known as ICUMSA numbers; lower numbers indicate a higher level of purity in the refined sugar.
Refined sugar is widely used for industrial needs for higher quality. Refined sugar is purer (ICUMSA below 300) than raw sugar (ICUMSA over 1,500). The level of purity associated with the colors of sugar, expressed by standard number ICUMSA, the smaller ICUMSA numbers indicate the higher purity of sugar.
The five largest producers of sugar in 2011 were Brazil, India, the European Union, China and Thailand. In the same year, the largest exporter of sugar was Brazil, distantly followed by Thailand, Australia and India. The largest importers were the European Union, United States and Indonesia. At present, Brazil has the highest per capita consumption of sugar, followed by Australia, Thailand, and the European Union.
World sugar production (1000 metric tons)
In most parts of the world, sugar is an important part of the human diet, making food more palatable and providing food energy. After cereals and vegetable oils, sugar derived from sugarcane and beet provided more kilocalories per capita per day on average than other food groups. According to the FAO, an average of 24 kilograms (53 lb) of sugar, equivalent to over 260 food calories per day, was consumed annually per person of all ages in the world in 1999. Even with rising human populations, sugar consumption is expected to increase to 25.1 kilograms (55 lb) per person per year by 2015.
The per capita consumption of refined sugar in the United States has varied between 27 and 46 kilograms (60 and 101 lb) in the last 40 years. In 2008, American per capita total consumption of sugar and sweeteners, exclusive of artificial sweeteners, equalled 61.9 kg (136 lb) per year. This consisted of 29.65 kg (65.4 lb) pounds of refined sugar and 31 kg (68.3 lb) pounds of corn-derived sweeteners per person.
Brown and white granulated sugar are 97% to nearly 100% carbohydrates, respectively, with less than 2% water, and no dietary fiber, protein or fat (table). Brown sugar contains a moderate amount of iron (15% of the Reference Daily Intake in a 100 gram amount, see table), but a typical serving of 4 grams (one teaspoon), would provide 15 calories and a negligible amount of iron or any other nutrient. Because brown sugar contains 5-10% molasses reintroduced during processing, its value to some consumers is a richer flavor than white sugar.
Studies examining the health impact of sugars are inconclusive. The United Nations meta-analysis and WHO studies showed contrasting impacts of sugar in refined and unrefined forms. Other studies indicated variable results between health effects, particularly on obesity, and whether the research was funded by the sugar industry or those by independent sponsors. The 'empty calories' argument is that a diet high in added sugar will reduce consumption of foods that contain essential nutrients.
Sugar addiction is the term for the relationship between sugar and the various aspects of food addiction including "bingeing, withdrawal, craving and cross-sensitization". Some scientists assert that consumption of sweets or sugar could have a heroin addiction-like effect, but recent reviews suggest that sugar addiction does not occur in humans.
Carbohydrates are classified according to their glycemic index, a system for measuring how quickly a food that is eaten raises blood sugar levels, and glycemic load, which takes into account both the glycemic index and the amount of carbohydrate in the food. This has led to carbohydrate counting, a method used by diabetics for planning their meals.
Studies in animals have suggested that chronic consumption of refined sugars can contribute to metabolic and cardiovascular dysfunction. Some experts have suggested that refined fructose is more damaging than refined glucose in terms of cardiovascular risk. Cardiac performance has been shown to be impaired by switching from a carbohydrate diet including fiber to a high-carbohydrate diet. Switching from saturated fatty acids to carbohydrates with high glycemic index values shows a statistically-significant increase in the risk of myocardial infarction. Other studies have shown that the risk of developing coronary heart disease is decreased by adopting a diet high in polyunsaturated fatty acids but low in sugar, whereas a low-fat, high-carbohydrate diet brings no reduction. This suggests that consuming a diet with a high glycemic load typical of the "junk food" diet is strongly associated with an increased risk of developing coronary heart disease.
The consumption of added sugars has been positively associated with multiple measures known to increase cardiovascular disease risk amongst adolescents as well as adults. Studies are suggesting that the impact of refined carbohydrates or high glycemic load carbohydrates are more significant than the impact of saturated fatty acids on cardiovascular disease. A high dietary intake of sugar (in this case, sucrose or disaccharide) can substantially increase the risk of heart and vascular diseases. According to a Swedish study of undertaken by Lund University and Malmö University College, sugar was associated with higher levels of bad blood lipids, causing a high level of small and medium low-density lipoprotein (LDL) and reduced high-density lipoprotein (HDL). In contrast, the amount of fat eaten did not affect the level of blood fats. Incidentally quantities of alcohol and protein were linked to an increase in the good HDL blood fat.
There is a common notion that sugar leads to hyperactivity, in particular in children, but studies and meta-studies question or address this issue. Some articles and studies do refer to the increasing evidence supporting the links between refined sugar and hyperactivity. The WHO FAO meta-study suggests that such inconclusive results are to be expected when some studies do not effectively segregate or control for free sugars as opposed to sugars still in their natural form (entirely unrefined) while others do. One study followed thirty-five 5-to-7-year-old boys who were reported by their mothers to be behaviorally "sugar-sensitive." They were randomly assigned to experimental and control groups. In the experimental group, mothers were told that their children were fed sugar, and, in the control group, mothers were told that their children received a placebo. In fact, all children received the placebo, but mothers in the sugar expectancy condition rated their children as significantly more hyperactive. This result suggests that the real effect of sugar is that it increases worrying among parents with preconceived notions.
Controlled trials have now shown unequivocally that consumption of sugar-sweetened beverages increases body weight and body fat, and that replacement of sugar by artificial sweeteners reduces weight. Studies on the link between sugars and diabetes are inconclusive, with some suggesting that eating excessive amounts of sugar does not increase the risk of diabetes, although the extra calories from consuming large amounts of sugar can lead to obesity, which may itself increase the risk of developing this metabolic disorder. Other studies show correlation between refined sugar (also called "free sugar") consumption and the onset of diabetes, and negative correlation with the consumption of fiber. These included a 2010 meta-analysis of eleven studies involving 310,819 participants and 15,043 cases of type 2 diabetes.
This found that "SSBs (sugar-sweetened beverages) may increase the risk of metabolic syndrome and type 2 diabetes not only through obesity but also by increasing dietary glycemic load, leading to insulin resistance, ?-cell dysfunction, and inflammation". As an overview to consumption related to chronic disease and obesity, the World Health Organization's independent meta-studies specifically distinguish 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") from sugars occurring naturally in food. The reports prior to 2000 set the limits for free sugars at a maximum of 10% of carbohydrate intake, measured by energy, rather than mass, and since 2002 have aimed for a level across the entire population of less than 10%. The consultation committee recognized that this goal is "controversial. However, the Consultation considered that the studies showing no effect of free sugars on excess weight have limitations". A 2015 New York Times report noted that "a review of beverage studies, published in the journal PLOS Medicine, found that those funded by Coca-Cola, PepsiCo, the American Beverage Association and the sugar industry were five times more likely to find no link between sugary drinks and weight gain than studies whose authors reported no financial conflicts."
In regard to contributions to tooth decay, the role of free sugars is also recommended to be below an absolute maximum of 10% of energy intake, with a minimum of zero. There is "convincing evidence from human intervention studies, epidemiological studies, animal studies and experimental studies, for an association between the amount and frequency of free sugars intake and dental caries" while other sugars (complex carbohydrate) consumption is normally associated with a lower rate of dental caries. Lower rates of tooth decay have been seen in individuals with hereditary fructose intolerance. Also, studies have shown that the consumption of sugar and starch have different impacts on oral health with the ingestion of starchy foods and fresh fruit being associated with low levels of dental caries.
The World Health Organization recommends that both adults and children reduce the intake of free sugars to less than 10% of total energy intake. A reduction to below 5% of total energy intake brings additional health benefits, especially in what regards dental caries (cavities in the teeth). These recommendations were based on the totality of available evidence reviewed regarding the relationship between free sugars intake and body weight and dental caries. Free sugars include monosaccharides and disaccharides added to foods and beverages by the manufacturer, cook or consumer, and sugars naturally present in honey, syrups, fruit juices and fruit juice concentrates.
On May 20, 2016 the U.S. Food and Drug Administration announced changes to the Nutrition Facts panel displayed on all foods, to be effective by July 2018. New to the panel is a requirement to list "Added sugars" by weight and as a percent of Daily Value (DV). For vitamins and minerals the intent of DVs is to indicate how much should be consumed. For added sugars, the guidance is that 100% DV should not be exceeded. 100% DV is defined as 50 grams. For a person consuming 2000 calories a day, 50 grams, the amount to not exceed, is the same as 200 calories, and thus 10% of total calories - same guidance as the World Health Organization. To put this into context, most 12 ounce (335 mL) cans of soda contain 39 grams of sugar. In the United States, a recently published government survey on food consumption reported that for men and women ages 20 and older the average total sugar intakes - naturally occurring in foods and added - were, respectively, 125 and 99 g/day.
Various culinary sugars have different densities due to differences in particle size and inclusion of moisture.
The "Engineering Resources - Bulk Density Chart" published in Powder and Bulk gives different values for the bulk densities: