Sugar

Sugar is a class of sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose, fructose and galactose. Compound sugars, also called disaccharides or double sugars, are molecules made of two bonded monosaccharides; common examples are sucrose (glucose + fructose), lactose (glucose + galactose) and maltose (two molecules of glucose). White sugar is almost pure sucrose. During digestion, compound sugars are hydrolysed into simple sugars.

Longer chains of saccharides 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 efficient for 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, as it occurs only 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 added to commercially available ultra-processed food and beverages, and is used as a sweetener for foods (e.g., toast and cereal) and beverages (e.g., coffee and tea). Globally, on average, a person consumes about of sugar each year. North and South Americans consume up to , and Africans consume under .

The use of added sugar in food and beverage manufacturing is a concern for elevated calorie intake, which is associated with an increased risk of several diseases, such as obesity, diabetes and cardiovascular disorders. In 2015 the World Health Organization recommended that adults and children should reduce their intake of free sugars to less than 10% of their total energy intake, encouraging a reduction to below 5%.

Etymology The etymology of sugar reflects the commodity's spread. From Sanskrit , meaning "ground or candied sugar", came Persian and Arabic sukkar. The Arabic word was borrowed in Medieval Latin as succarum, whence came the 12th-century Old French sucre and the English sugar. Sugar was introduced into Europe by the Arabs in Sicily and Spain.

The English word jaggery, a coarse brown sugar made from date palm sap or sugarcane juice, has a similar etymological origin: Portuguese from the Malayalam , which is from the Sanskrit .

History

Sugar was first produced from sugar cane in the Indian subcontinent. Diverse species of sugar cane seem to have originated from India (Saccharum barberi and S. edule) and New Guinea (S. officinarum). Sugarcane is described in Chinese manuscripts dating to the 8th century BCE, which state that the use of sugarcane originated in India.

Nearchus (admiral of Alexander the Great), the Greek physician Pedanius Dioscorides and the Roman Pliny the Elder also described sugar. In the mid-15th century, sugar was introduced into Madeira and the Canary Islands, where it was mass-produced. Christopher Columbus introduced it to the New World, leading to sugar industries in Cuba and Jamaica by the 1520s. The Portuguese took sugar cane to Brazil.

Beet sugar, the starting point for the modern sugar industry, was a German invention. Beet sugar was first produced industrially in 1801 in Cunern, Prussia.

Sugar became a household item by the 19th century, and 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 colonisation and industrialisation of previously under-developed lands. It was also intimately associated with slavery. World consumption increased more than 100 times from 1850 to 2000, led by the United Kingdom, where it increased from about 2 pounds per head per year in 1650 to 90 pounds by the early 20th century.

Chemistry

Scientifically, sugar loosely refers to a number of compounds typically with the formula (CH2O)n. Some large classes of sugars, ranked in increasing order of molecular weight are monosaccharides, disaccharides, or oligosaccharides.

Monosaccharides

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". Such labels may also refer to any types of these compounds. Fructose, galactose and glucose are all simple sugars, monosaccharides, with the general formula . 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 polarised light to diverge to the right or the left.

Fructose, or fruit sugar, occurs naturally in fruits, some root vegetables, cane sugar and honey and is the sweetest of the sugars. It is one of the components of sucrose or table sugar. It is used as a high-fructose syrup, which is manufactured from hydrolysed corn starch that has been processed to yield corn syrup, with enzymes then added to convert part of the glucose into fructose. Galactose generally does not occur in the free state but is a constituent with glucose of the disaccharide lactose or milk sugar. It is less sweet than glucose. It is a component of the antigens found on the surface of red blood cells that determine blood groups. Glucose occurs naturally in fruits and plant juices and is the primary product of photosynthesis. Starch is converted into glucose during digestion, and glucose is the form of sugar that is transported around the bodies of animals in the bloodstream. Although in principle there are two enantiomers of glucose (mirror images one of the other), naturally occurring glucose is D-glucose. This is also called dextrose, or grape sugar because drying grape juice produces crystals of dextrose that can be sieved from the other components.

The acyclic monosaccharides (and disaccharides) contain either aldehyde groups or ketone groups. These carbon-oxygen double bonds (C=O) are the reactive centres. 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.

Disaccharides

Lactose, maltose and sucrose are disaccharides, also called "compound sugars". They share the formula . They are formed by the condensation of two monosaccharide molecules with the expulsion of a molecule of water.

Lactose is the naturally occurring sugar found in milk. A molecule of lactose is formed by the combination of a molecule of galactose with a molecule of glucose. It is broken down when consumed into its constituent parts by the enzyme lactase during digestion. Children have this enzyme, but some adults no longer form it and they are unable to digest lactose. Maltose is formed during the germination of certain grains, the most notable being barley, which is converted into malt, the source of the sugar's name. A molecule of maltose is formed by the combination of two molecules of glucose. It is less sweet than glucose, fructose or sucrose. 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. 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. 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.

Polysaccharides Longer than disaccharides are oligosaccharides and polysaccharides. Cellulose and chitin are polymers, often crystalline, found in diverse plants and insects, respectively. Cellulose cannot be digested directly by animals. Starch is an amorphous polymer of glucose that is found in many plants and is widely used in the sugar industry.

Sources The sugar contents of common fruits and vegetables are presented in Table 1.

+Table 1. Sugar content of selected common plant foods (g/100g)Use link to FoodData Central (USDA) and then search for the particular food, and click on "SR Legacy Foods".Food itemTotalcarbohydrateincludingdietary fiberTotalsugarsFreefructoseFreeglucoseSucroseFructose/(Fructose+Glucose)ratioSucroseas a % oftotal sugarsFruits        Apple 13.8 10.4 5.9 2.4 2.1 0.67 20 Apricot 11.1 9.2 0.9 2.4 5.9 0.42 64 Banana 22.8 12.2 4.9 5.0 2.4 0.5 20 Fig, dried 63.9 47.9 22.9 24.8 0.9 0.481.9 Grapes 18.1 15.5 8.1 7.2 0.2 0.53 1 Navel orange 12.5 8.5 2.25 2.0 4.3 0.51 51 Peach 9.5 8.4 1.5 2.0 4.8 0.47 57 Pear 15.5 9.8 6.2 2.8 0.8 0.67 8 Pineapple 13.1 9.9 2.1 1.7 6.0 0.52 61 Plum 11.4 9.9 3.1 5.1 1.6 0.40 16 Strawberry 7.68 4.89 2.441 1.99 0.47 0.5510Vegetables        Beet, red 9.6 6.8 0.1 0.1 6.50.50 96 Carrot 9.6 4.7 0.6 0.6 3.6 0.50 77 Corn, sweet 19.0 6.2 1.9 3.4 0.9 0.38 15 Red pepper, sweet 6.0 4.2 2.3 1.9 0.0 0.55 0 Onion, sweet 7.6 5.0 2.0 2.3 0.7 0.47 14 Sweet potato20.1 4.2 0.7 1.0 2.5 0.47 60 Yam 27.9 0.5 tr tr tr na tr Sugar cane 13–18 0.2–1.0 0.2–1.0 11–16 0.50 high Sugar beet 17–18 0.1–0.5 0.1–0.516–17 0.50 high The carbohydrate figure is calculated in the United States Department of Agriculture database and does not always correspond to the sum of the sugars, the starch, and the dietary fibre. The fructose to fructose plus glucose ratio is calculated by including the fructose and glucose coming from the sucrose.

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.

Sugar In 2022–23 world production of sugar was 186 million tonnes, and in 2023–2024 an estimated 194 million tonnes – a surplus of 5 million tonnes, according to Ragus.

Sugarcane

Sugarcane production – 2022 (millions of tonnes) 724.4 439.4 103.4 92.1 World 1,922.1Source: FAO

Sugar cane accounted for around 21% of the global crop production over the 2000–2021 period. The Americas was the leading region in the production of sugar cane (52% of the world total). Global production of sugarcane in 2022 was 1.9 billion tonnes, with Brazil producing 38% of the world total and India 23% (table).

Sugarcane is 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.