Sugar

Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Table sugar, granulated sugar, or regular sugar, refers to sucrose, a disaccharide composed of glucose and fructose.
Simple sugars, also called monosaccharides, include glucose, fructose, and galactose. Compound sugars, also called disaccharides or double sugars, are molecules composed of two monosaccharides joined by a glycosidic bond. Common examples are sucrose (table sugar) (glucose + fructose), lactose (glucose + galactose), and maltose (two molecules of glucose). In the body, compound sugars are hydrolysed into simple sugars.
Longer chains of monosaccharides are not regarded as sugars, and are called oligosaccharides or polysaccharides. Starch is a glucose polymer found in plants, and is the most abundant source of energy in human food. Some other chemical substances, such as glycerol and sugar alcohols, may have a sweet taste, but are not classified as sugar.
Sugars are found in the tissues of most plants. Honey and fruit are abundant natural sources of unbounded simple sugars. Sucrose is especially concentrated in sugarcane and sugar beet, making them ideal for efficient commercial extraction to make refined sugar. In 2016, the combined world production of those two crops was about two billion tonnes. Maltose may be produced by malting grain. Lactose is the only sugar that cannot be extracted from plants. It can only be found in milk, including human breast milk, and in some dairy products. A cheap source of sugar is corn syrup, industrially produced by converting corn starch into sugars, such as maltose, fructose and glucose.
Sucrose is used in prepared foods (e.g. cookies and cakes), is sometimes added to commercially available processed food and beverages, and may be used by people as a sweetener for foods (e.g. toast and cereal) and beverages (e.g. coffee and tea). The average person consumes about of sugar each year, with North and South Americans consuming up to and Africans consuming under . As sugar consumption grew in the latter part of the 20th century, researchers began to examine whether a diet high in sugar, especially refined sugar, was damaging to human health. Excessive consumption of sugar has been implicated in the onset of obesity, diabetes, cardiovascular disease, dementia, and tooth decay. Numerous studies have tried to clarify those implications, but with varying results, mainly because of the difficulty of finding populations for use as controls that consume little or no sugar. In 2015, the World Health Organization recommended that adults and children reduce their intake of free sugars to less than 10%, and encouraged a reduction to below 5%, of their total energy intake.
Etymology.
The etymology reflects the spread of the commodity. From Sanskrit ("śarkarā"), meaning "ground or candied sugar", came Persian "shakar", then to 12th century French "sucre" and the English "sugar".
The English word "jaggery", a coarse brown sugar made from date palm sap or sugarcane juice, has a similar etymological origin: Portuguese "jágara" from the Malayalam "cakkarā", which is from the Sanskrit "śarkarā".
History.
Ancient world to Renaissance.
Asia.
Sugar has been produced in the Indian subcontinent since ancient times and its cultivation spread from there into modern-day Afghanistan through the Khyber Pass. It was not plentiful nor cheap in early times, and in most parts of the world, honey was more often used for sweetening. Originally, people chewed raw sugarcane to extract its sweetness. Sugarcane was a native of tropical areas such as the Indian subcontinent (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 to 8th century BCE, which state that the use of sugarcane originated in India.
In the tradition of Indian medicine (āyurveda), the sugarcane is known by the name "Ikṣu" and the sugarcane juice is known as "Phāṇita". Its varieties, synonyms and characteristics are defined in nighaṇṭus such as the Bhāvaprakāśa (1.6.23, group of sugarcanes).
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: खण्ड, ), which is the source of the word "candy". Indian sailors, who carried clarified butter and sugar as supplies, introduced knowledge of sugar along the various trade routes they travelled. Traveling Buddhist monks took 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 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 the Indian subcontinent, the Middle East and China, sugar became a staple of cooking and desserts.
Europe.
Nearchus, admiral of Alexander of Macedonia, knew of sugar during the year 325 BC, because of his participation in the campaign of India led by Alexander ("Arrian, Anabasis"). 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." Crusaders brought sugar back 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. It supplemented the use of 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 center in Europe.
There was a drastic change in the mid-15th century, when São Tomé, Madeira, and the Canary Islands were settled from Europe, and sugar grown there. After this an "all-consuming passion for sugar ... swept through society" as it became far more easily available, though initially still very expensive. By 1492, Madeira was producing over of sugar annually. Genoa, one of the centers of distribution, became known for candied fruit, while Venice specialized in pastries, sweets (candies), and sugar sculptures. Sugar was considered to have "valuable medicinal properties" as a "warm" food under prevailing categories, being "helpful to the stomach, to cure cold diseases, and sooth lung complaints".
A feast given in Tours in 1457 by Gaston de Foix, which is "probably the best and most complete account we have of a late medieval banquet" includes the first mention of sugar sculptures, as the final food brought in was "a heraldic menagerie sculpted in sugar: lions, stags, monkeys ... each holding in paw or beak the arms of the Hungarian king". Other recorded grand feasts in the decades following included similar pieces. Originally the sculptures seem to have been eaten in the meal, but later they become merely table decorations, the most elaborate called "triomfi". Several significant sculptors are known to have produced them; in some cases their preliminary drawings survive. Early ones were in brown sugar, partly cast in molds, with the final touches carved. They continued to be used until at least the Coronation Banquet for Edward VII of the United Kingdom in 1903; among other sculptures every guest was given a sugar crown to take away.
Modern history.
In August 1492, Christopher Columbus collected sugar cane samples in La Gomera in the Canary Islands, and introduced it to the New World. The cuttings were planted and the first sugar-cane harvest in Hispaniola took place in 1501. 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. It took until 1600 for Brazilian sugar production to exceed that of São Tomé, which was the main center of sugar production in sixteenth century.
Sugar was a luxury in Europe until the early 19th century, when it became more widely available, due to the rise of beet sugar in Prussia, and later in France under Napoleon. Beet sugar was a German invention, since, in 1747, Andreas Sigismund Marggraf announced the discovery of sugar in beets and devised a method using alcohol to extract it. Marggraf's student, Franz Karl Achard, devised an economical industrial method to extract the sugar in its pure form in the late 18th century. Achard first produced beet sugar in 1783 in Kaulsdorf, and in 1801, the world's first beet sugar production facility was established in Cunern, Silesia (then part of Prussia). The works of Marggraf and Achard were the starting point for the sugar industry in Europe, and for the modern sugar industry in general, since sugar was no longer a luxury product and a product almost only produced in warmer climates.
Sugar became highly popular and by the 19th century, was found in every household. This evolution of taste and demand for sugar as an essential food ingredient resulted in major economic and social changes. Demand drove, in part, the colonization of tropical islands and areas where labor-intensive sugarcane plantations and sugar manufacturing facilities could be successful.
After slavery was abolished, the demand for workers in European colonies in the Caribbean was filled by indentured laborers from Indian subcontinent. Millions of enslaved or indentured laborers were brought to various European colonies in the Americas, Africa and Asia (as a result of demand in Europe for among other commodities, sugar), influencing the ethnic mixture of numerous nations around the globe.
Sugar also led to some industrialization of areas where sugar cane was grown. For example, in the 1790s Lieutenant J. Paterson, of the Bengal Presidency promoted to the British parliament the idea that sugar cane could grow in British India, where it had started, 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 also 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 produce sugar in cube form was Moravian Jakub Kryštof Rad, director of a sugar company in Dačice. 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.
Sugar was rationed during World War I and more sharply during World War II. This led to the development and use of various artificial sweeteners.
Chemistry.
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.
Natural polymers.
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 .
Flammability and heat response.
Because sugars burn easily when exposed to flame, the handling of sugars risks dust explosion. The risk of explosion is higher when the sugar has been milled to superfine texture, such as for use in chewing gum. The 2008 Georgia sugar refinery explosion, which killed 14 people and injured 36, and destroyed most of the refinery, was caused by the ignition of sugar dust.
In its culinary use, exposing sugar to heat causes caramelization. As the process occurs, volatile chemicals such as diacetyl are released, producing the characteristic caramel flavor.
Types.
Monosaccharides.
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.
Disaccharides.
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.
Sources.
The sugar contents of common fruits and vegetables are presented in Table 1.
The fructose to fructose plus glucose ratio is calculated by including the fructose and glucose coming from the sucrose.
In November 2019, scientists reported detecting, for the first time, sugar molecules, including ribose, in meteorites, suggesting that chemical processes on asteroids can produce some fundamentally essential bio-ingredients important to life, and supporting the notion of an RNA World prior to a DNA-based origin of life on Earth, and possibly, as well, the notion of panspermia.
Production.
Due to rising demand, sugar production in general increased some 14% over the period 2009 to 2018. The largest importers were China, Indonesia, and the United States.
Sugarcane.
Global production of sugarcane in 2016 was 1.9 billion tonnes, with Brazil producing 41% of the world total and India 18% (table).
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 the Indian subcontinent and Southeast Asia over centuries for the sucrose 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 for the labor-intensive process resulted in sugar production, enabling prices cheap enough for most people to buy. Mechanization reduced some labor needs, but in the 21st century, cultivation and production relied on low-wage laborers.
Sugar cane requires a frost-free climate with sufficient rainfall during the growing season to make full use of the plant's substantial 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) where it is either milled and the juice extracted with water or extracted by diffusion. The juice is 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. The resulting supersaturated solution is seeded with sugar crystals, facilitating crystal formation and drying. 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, can be bleached by sulfur dioxide, or can be treated in a carbonatation process to produce a whiter product. About of irrigation water is needed for every one kilogram (2.2 pounds) of sugar produced.
Sugar beet.
In 2016, global production of sugar beets was 277 million tonnes, led by Russia with 19% of the world total (table).
The 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 the field for some weeks before being transported to the processing plant where the crop is washed and sliced, and the sugar extracted by diffusion. Milk of lime is added to the raw juice with calcium carbonate. After water is evaporated by boiling the syrup under a vacuum, the syrup is cooled and seeded with sugar crystals. The white sugar that crystallizes can be separated in a centrifuge and dried, requiring no further refining.
Refining.
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.
Forms and uses.
Brown sugars.
Brown sugars are granulated sugars, either containing residual molasses, or with the grains deliberately coated with molasses to produce a light- or dark-colored sugar. They are used in baked goods, confectionery, and toffees. Their darkness is due to the amount of molasses they contain. They may be classified based on their darkness or country of origin. For instance:
Consumption.
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 one source, per capita consumption of sugar in 2016 was highest in the United States, followed by Germany and the Netherlands.
Nutrition and flavor.
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.
Health effects.
Sugar industry funding and health information.
Sugar refiners and manufacturers of sugary foods and drinks have sought to influence medical research and public health recommendations, with substantial and largely clandestine spending documented from the 1960s to 2016. The results of research on the health effects of sugary food and drink differ significantly, depending on whether the researcher has financial ties to the food and drink industry. A 2013 medical review concluded that "unhealthy commodity industries should have no role in the formation of national or international NCD [non-communicable disease] policy".
There have been similar efforts to steer coverage of sugar-related health information in popular media, including news media and social media.
Obesity and metabolic syndrome.
A 2003 World Health Organization technical report provided evidence that high intake of sugary drinks (including fruit juice) increased the risk of obesity by adding to overall energy intake. By itself, sugar is not a factor causing obesity and metabolic syndrome, but rather – when over-consumed – is a component of unhealthy dietary behavior. Meta-analyses showed that excessive consumption of sugar-sweetened beverages increased the risk of developing type 2 diabetes and metabolic syndrome – including weight gain and obesity – in adults and children.
Hyperactivity.
A 2019 meta-analysis found that sugar consumption does not improve mood, but can lower alertness and increase fatigue within an hour of consumption. Some studies report evidence of causality between high consumption of refined sugar and hyperactivity. One review of low-quality studies of children consuming high amounts of energy drinks showed association with higher rates of unhealthy behaviors, including smoking and excessive alcohol use, and with hyperactivity and insomnia.
Tooth decay.
The 2003 WHO report stated that "Sugars are undoubtedly the most important dietary factor in the development of dental caries". A review of human studies showed that the incidence of caries is lower when sugar intake is less than 10% of total energy consumed.
Nutritional displacement.
The "empty calories" argument states that a diet high in added sugar will reduce consumption of foods that contain essential nutrients. This nutrient displacement occurs if sugar makes up more than 25% of daily energy intake, a proportion associated with poor diet quality and risk of obesity. Displacement may occur at lower levels of consumption.
Alzheimer's disease.
Claims have been made of a sugar–Alzheimer's disease connection, but there is inconclusive evidence that cognitive decline is related to dietary fructose or overall energy intake.
Recommended dietary intake.
The World Health Organization recommends that both adults and children reduce the intake of free sugars to less than 10% of total energy intake, and suggests a reduction to below 5%. "Free sugars" include monosaccharides and disaccharides added to foods, and sugars found in fruit juice and concentrates, as well as in honey and syrups. According to the WHO, "[t]hese recommendations were based on the totality of available evidence reviewed regarding the relationship between free sugars intake and body weight (low and moderate quality evidence) and dental caries (very low and moderate quality evidence)."
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 is equal to 200 calories and thus 10% of total calories—the same guidance as the World Health Organization. To put this in context, most 355 mL (12 US fl oz) cans of soda contain 39 grams of sugar. In the United States, a government survey on food consumption in 2013–2014 reported that, for men and women aged 20 and older, the average total sugar intakes—naturally occurring in foods and added—were, respectively, 125 and 99 g/day.
Measurements.
Various culinary sugars have different densities due to differences in particle size and inclusion of moisture.
Domino Sugar gives the following weight to volume conversions (in United States customary units):
The "Engineering Resources – Bulk Density Chart" published in "Powder and Bulk" gives different values for the bulk densities:
Society and culture.
Manufacturers of sugary products, such as soft drinks and candy, and the Sugar Research Foundation have been accused of trying to influence consumers and medical associations in the 1960s and 1970s by creating doubt about the potential health hazards of sucrose overconsumption, while promoting saturated fat as the main dietary risk factor in cardiovascular diseases. In 2016, the criticism led to recommendations that diet policymakers emphasize the need for high-quality research that accounts for multiple biomarkers on development of cardiovascular diseases.