Longer chains of monosaccharides (>2) are not regarded as sugars and are called oligosaccharides or polysaccharides. Starch is a glucose polymer found in plants, the most abundant source of energy in human food. Some other chemical substances, such as ethylene glycol, 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 fruits are abundant natural sources of 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 ultra-processed food and beverages, and is sometimes used as a sweetener for foods (e.g., toast and cereal) and beverages (e.g., coffee and tea). The average person consumes about 24 kilograms (53 pounds) of sugar each year. North and South Americans consume up to 50 kg (110 lb), and Africans consume under 20 kg (44 lb).[1]
As free sugar consumption grew in the latter part of the 20th century, researchers began to examine whether a diet high in free sugar, especially refined sugar, was damaging to human health. In 2015, the World Health Organization strongly recommended that adults and children reduce their intake of free sugars to less than 10% of their total energy intake and encouraged a reduction to below 5%.[2] In general, high sugar consumption damages human health more than it provides nutritional benefit and is associated with a risk of cardiometabolic and other health detriments.[3]
The etymology of sugar reflects the commodity's spread. From Sanskrit śarkarā, meaning "ground or candied sugar", came Persian shakar and Arabic sukkar. The Arabic word was borrowed in Medieval Latin as succarum, whence came the 12th century French sucre and the English sugar. Sugar was introduced into Europe by the Arabs in Sicily and Spain.[4]
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.[5]
Roman Pliny the Elder also described sugar in his 1st century CE 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."[26] 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, the Republic of 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.[27] Crusade chronicler William of Tyre, writing in the late 12th century, described sugar as "very necessary for the use and health of mankind".[28] In the 15th century, Venice was the chief sugar refining and distribution center in Europe.[14]
There was a drastic change in the mid-15th century, when Madeira and the Canary Islands were settled from Europe and sugar introduced there.[29][30] After this an "all-consuming passion for sugar ... swept through society" as it became far more easily available, though initially still very expensive.[31] By 1492, Madeira was producing over 1,400,000 kilograms (3,000,000 lb) of sugar annually.[32] 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".[33]
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".[34] Other recorded grand feasts in the decades following included similar pieces.[35] Originally the sculptures seem to have been eaten in the meal, but later they become merely table decorations, the most elaborate called trionfi. 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.[36]
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.[51][52][53]
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.[54][55] 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.[56]
Until the late nineteenth century, sugar was purchased in loaves, which had to be cut using implements called sugar nips.[57] 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 Jakob Christof Rad, director of a sugar refinery in Dačice. In 1841, he produced the first sugar cube in the world.[58] He began sugar-cube production after being granted a five-year patent for the process on 23 January 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.[59]
Sugar was rationed during World War I, though it was said that "No previous war in history has been fought so largely on sugar and so little on alcohol",[60] and more sharply during World War II.[61][62][63][64][65] Rationing led to the development and use of various artificial sweeteners.[61][66]
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 C
nH
2nO
n with n between 3 and 7 (deoxyribose being an exception). Glucose has the molecular formula C
6H
12O
6. 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 (H
2O) per bond.[67]
Monosaccharides in a closed-chain form can form glycosidic bonds with other monosaccharides, creating disaccharides (such as sucrose) and polysaccharides (such as starch or cellulose). 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.[67]
Natural polymers
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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 (C
6H
12O
6) or (as in cane and beet) sucrose (C
12H
22O
11). 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.[67] 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.[68] DNA and RNA are built up of the monosaccharides deoxyribose and ribose, respectively. Deoxyribose has the formula C
5H
10O
4 and ribose the formula C
5H
10O
5.[69]
Flammability and heat response
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Magnification of grains of refined sucrose, the most common free sugar
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.[70] 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.[71]
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.[72]
or sucrose.[73] It is formed in the body during the digestion of starch by the enzyme amylase and is itself broken down during digestion by the enzyme maltase.[81]
Sucrose is found in the stems of sugarcane and roots of sugar beet. It also occurs naturally alongside fructose and glucose in other plants, in particular fruits and some roots such as carrots. The different proportions of sugars found in these foods determines the range of sweetness experienced when eating them.[73] A molecule of sucrose is formed by the combination of a molecule of glucose with a molecule of fructose. After being eaten, sucrose is split into its constituent parts during digestion by a number of enzymes known as sucrases.[82Manufacturers 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.[116] 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.[116]
Originally, no sugar was white; anthropologist Sidney Mintz writes that white likely became understood as the ideal after groups who associated the color white with purity transferred their value to sugar.[155] In India, sugar frequently appears in religious observances. For ritual purity, such sugar cannot be white.[155]