Longer chains of monosaccharides (>2) are not considered sugars and are called oligosaccharides or polysaccharides. Starch, a glucose polymer found in plants, is the most abundant source of energy in human food. Some other chemicals, such as glycerol and sugar alcohols, may have a sweet taste but are not sugars.
Sugar is found in the tissues of most plants. Honey and fruit are rich natural sources of simple sugars. Sucrose is particularly concentrated in sugar cane and sugar beets, making it ideal for efficient commercial extraction to make refined sugar. In 2016, the combined world production of these two crops was about 2 billion tonnes. Maltose can be produced from malted grains. Lactose is the only sugar that cannot be extracted from plants. It is only found in milk (including human breast milk) and some dairy products. An inexpensive source of sugar is corn syrup, which is produced industrially by converting corn starch into sugars such as maltose, fructose, and glucose.
Sucrose is used in prepared foods (such as cookies and cakes) and is sometimes added to commercially available processed foods and beverages, where people can use it as a sweetener for foods (such as toast and cereal) and beverages (such as coffee and tea). The average person consumes about 24 kg (53 lb) of sugar per year, with North and South Americans consuming up to 50 kg (110 lb) and Africans less than 20 kg (44 lb).
As sugar consumption increased in the second half of the 20th century, researchers began to investigate whether diets high in sugar, especially refined sugar, could harm human health. Excessive intake of sugar has been linked to the development of obesity, diabetes, cardiovascular disease, and tooth decay. Numerous studies have attempted to clarify these effects, with varying results, mainly because it is difficult to find control groups that eat 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 reducing their total energy intake to less than 5%.
Sugar production increased by around 14% overall between 2009 and 2018 due to rising demand. The largest importers are China, Indonesia, and the United States.
Global sugarcane production in 2016 was 1.9 billion tonnes, with Brazil accounting for 41% of the world total and India 18%.
Sugarcane refers to any one of several giant types of grass of the genus Sugarcane of the Poaceae family or their hybrids. They have been cultivated in tropical climates of the Indian subcontinent and Southeast Asia for centuries because of the sucrose in their stems. In the 18th century, with the establishment of slave plantations in the Americas, sugar cane production increased dramatically. The use of slavery in a labor-intensive process led to the production of sugar, making it cheap enough for most people to buy it. Mechanization has reduced some labor requirements, but in the 21st century, cultivation and production depend on low-wage labor.
Sugarcane requires a frost-free climate and adequate rainfall during the growing season to take full advantage of the plant's enormous growth potential. Crops are harvested mechanically or by hand, cut to length, and quickly transported to processing plants (often called sugar mills), where they are milled and the juice extracted with water or by diffusion. The juice is clarified with lime and heated to destroy the enzymes. The resulting thin syrup is concentrated in a series of evaporators, followed by further water removal. The resulting supersaturated solution is seeded with sugar crystals to promote crystal formation and drying. Molasses is a by-product of this process, and the fibers in the stems, called bagasse, are burned to provide energy for the sugar extraction process. Raw sugar crystals have a viscous brown coating that can either be used directly, bleached with sulfur dioxide, or treated during carbonation to produce a whiter product. Approximately 2,500 liters (660 US gallons) of irrigation water is required for each kilogram (2.2 lb) of sugar produced.
In 2016, the global sugar beet production was 277 million tons, led by Russia, which accounted for 19% of the world's total production.
Beets became a major source of sugar in the 19th century when methods of extracting the sugar became available. Amaranthaceae is a biennial plant cultivar with high sucrose content in tuberous roots. It is grown as a root crop in temperate regions with abundant rainfall and requires rich soil. Crops are harvested mechanically in the fall to remove leaf crowns and excess soil. The roots do not spoil quickly and may sit in the field for weeks before being transported to a processing plant where the crop is washed and sliced before the sugars are extracted by diffusion. Milk of lime is added to raw juice along with calcium carbonate. After boiling the syrup under a vacuum to evaporate the water, the syrup is cooled and seeded with sugar crystals. Crystallized white sugar can be separated and dried in a centrifuge without further refining.
Refined sugar is made from raw sugar that has undergone a refining process to remove molasses. Raw sugar is sucrose extracted from sugar cane or sugar beets. While raw sugar can be eaten, the refining process removes unwanted flavors and produces refined or white sugar.
Sugar can be shipped in bulk to the country where it will be used, where the refining process usually takes place. The first stage, called affinity, involves dipping sugar crystals into a concentrated syrup, softening and removing the sticky brown coating without dissolving them. The crystals are then separated from the liquid and dissolved in water. The resulting syrup is processed through a carbonation or phosphorylation process. Both involve the precipitation of fine solids in the syrup which, when filtered, removes many impurities at the same time. Color is removed by using granular activated carbon or ion exchange resins. The syrup is concentrated by boiling, then cooled and seeded with sugar crystals that crystallize the sugar. The liquor is centrifuged in a centrifuge, and the white crystals are dried in hot air, ready to be packaged or used. The remaining liquor is made into refined syrup.
The International Committee for the Harmonized Methods of Sugar Analysis has developed a measure of refined sugar purity called the ICUMSA number; a lower number indicates a higher purity of refined sugar.
Refined sugar is widely used for higher-quality industrial needs. Refined sugar (ICUMSA less than 300) is purer than raw sugar (ICUMSA more than 1,500). The level of purity associated with the color of the sugar, expressed in the standard number ICUMSA, with lower ICUMSA numbers indicating higher sugar purity.
Forms and uses
- Granulated sugar, also known as granulated sugar, is composed of reflective crystals with a particle size of about 1 to 3 mm, similar to table salt. Used in bakery products and candies, it will not dissolve when exposed to heat and moisture.
- Granulated sugar (about 0.6 mm crystals), also known as table sugar or regular sugar, is used at the table, sprinkled on food and to sweeten hot beverages (coffee and tea), and in-home baking to add sweetness and texture to baked products ( cookies and cakes) and desserts (puddings and ice cream). It is also used as a preservative to prevent microbial growth and spoilage of perishable foods such as preserves, jams, and marmalades.
- Ground sugar is ground into a fine powder. They are used for dusting food as well as baking and confectionery.
- Granulated sugar, sold in the U.S. as "superfine" sugar, is about 0.35 mm in size
- Powdered sugar, also known as confectioners' sugar or icing sugar, comes in different fines (for example, fine or 3X, very fine or 6X, extra fine or 10X). The superfine variety (sometimes called 10X) has a particle size of about 0.060 mm, which is about ten times smaller than granulated sugar.
- Snow powder, a non-melting powdered sugar that usually consists of glucose, not sucrose.
- Screening sugars are crystalline products separated by particle size. They are used in decorative table sugar, in mixing dry powders, and in baking and confectionery.
- Sugar cubes (sometimes called sugar cubes) are white or brown granulated sugar that is lightly steamed and pressed into cubes. They are used to sweeten drinks.
- Until the late 19th century, sweetbread was a common cone for the production and sale of refined sugar. This shape is still used in Germany (for preparing Feuerzangenbowle) as well as in Iran and Morocco.
Brown sugar is granulated sugar that either contains residual molasses or deliberately coats grains with molasses to create light or dark sugar. They are used in baked goods, candies and toffees. Their darkness is due to the high amount of molasses they contain. They can be classified according to their darkness or country of origin. For example:
- Light brown with very little molasses (about 3.5%)
- dark brown, high in molasses (about 6.5%)
- Non-centrifuged sucrose, unrefined, so very dark sucrose obtained by evaporating water from sugar cane juice, such as:
- Panela, also known as rapadura, chancaca, piloncillo.
- Some varieties of musk sugar, also known as Barbados sugar. Other varieties are partially refined by centrifugation or using a spray dryer.
- Some varieties of jaggery. Other varieties are produced from dates or palm juice rather than sugar cane juice.
- Honey contains mostly unconjugated fructose and glucose molecules, the viscous liquid that bees produce by digesting nectar.
- Syrups are viscous liquids consisting mainly of a solution of sugar in water. They are used in the food processing of a variety of products, including beverages, hard candy, ice cream, and jams.
- A syrup made by dissolving granulated sugar in water is sometimes called liquid sugar. Liquid sugar that is 50% sugar and 50% water is called simple syrup.
- Syrup can also be made by reducing naturally sweetened juices like sugar cane or maple sap.
- Corn syrup is made by converting cornstarch into sugars (mostly maltose and glucose).
- High fructose corn syrup (HFCS) is produced by further processing corn syrup to convert some of its glucose into fructose.
- Invert syrup, commonly known as invert syrup or invert sugar, is a mixture of two simple sugars (glucose and fructose) made by heating granulated sugar in water. It is used in bread, cakes, and beverages to adjust sweetness, help hydrate, and avoid sugar crystallization.
- Molasses and syrups are obtained by removing sugar from sugar cane or beet juice as a by-product of sugar production. They can be mixed with the aforementioned syrups to enhance the sweetness and used in a range of baked goods and confections, including toffee and licorice.
- Black molasses, also known as black syrup, has a darker color, less sugar, and a richer flavor. It is sometimes added to animal feed, processed into rum, or ethanol used as fuel.
- Compared to black belts, regular molasses and golden syrup are higher in sugar and lighter in color.
- During winemaking, fruit sugars are converted into alcohol through a fermentation process. If the grape juice formed by pressing the fruit is low in sugar, additional sugar can be added to increase the alcohol content of the wine in a process called sweetening. In the production of dessert wines, fermentation may stop before fermentation is complete, leaving some residual sugars that give the wine its sweetness.
- Low-calorie sweeteners are usually made from sweetened maltodextrin. Maltodextrin is an easily digestible synthetic polysaccharide consisting of short chains of three or more glucose molecules, made by the partial hydrolysis of starch. Strictly speaking, maltodextrin is not sugar because it contains more than two glucose molecules, although its structure is similar to maltose, which is a molecule made up of two linked glucose molecules.
- Polyols are sugar alcohols that are used in chewing gums that need to remain sweet in the mouth for a long time.
- Several different kinds of zero-calorie artificial sweeteners can also be used as sugar substitutes.
In most parts of the world, sugar is an important part of the human diet, making food more palatable and providing food energy. After grains and vegetable oils, sugar from sugar cane and beets provided an average of more kilocalories per day than the other food groups. In 1750, the average Englishman got 72 calories a day from sugar. In 1913, that number rose to 395. In 2015, it still provided about 14% of the calories in the British diet. In 2016, per capita sugar consumption was highest in the United States, followed by Germany and the Netherlands, according to a source.
Nutrition and flavor
Brown and white granulated sugar are respectively 97% to nearly 100% carbohydrates, contain less than 2% water, and contain no dietary fiber, protein, or fat. Brown sugar contains moderate amounts of iron (15% of the 100-gram RIDI), but a typical serving of 4 grams (one teaspoon) will provide 15 calories and negligible amounts of iron or any other nutrients. Since brown sugar contains 5-10% molasses reintroduced during processing, its value to some consumers is a richer flavor than white sugar.