Sucrose

Sucrose is common sugar. It is a disaccharide, a molecule composed of two monosaccharides: glucose and fructose. Sucrose is produced naturally in plants, from which table sugar is refined. It has the molecular formula C12H22O11. Sucrose is common sugar. It is a disaccharide, a molecule composed of two monosaccharides: glucose and fructose. Sucrose is produced naturally in plants, from which table sugar is refined. It has the molecular formula C12H22O11. For human consumption, sucrose is extracted, and refined, from either sugar cane or sugar beet. Sugar mills are located where sugarcane is grown to crush the cane and produce raw sugar which is shipped around the world for refining into pure sucrose. Some sugar mills also process the raw sugar into pure sucrose. Sugar beet factories are located in colder climates where the beet is grown, and process the beets directly into refined sugar. The sugar refining process involves washing the raw sugar crystals before dissolving them into a sugar syrup which is filtered and then passed over carbon to remove any residual colour. The, by now clear, sugar syrup is then concentrated by boiling under a vacuum and crystallized as the final purification process to produce crystals of pure sucrose. These crystals are clear, odourless, and have a sweet taste. En masse, the crystals appear white. Sugar is often an added ingredient in food production and food recipes. About 185 million tonnes of sugar were produced worldwide in 2017. The word sucrose was coined in 1857 by the English chemist William Miller from the French sucre ('sugar') and the generic chemical suffix for sugars -ose. The abbreviated term Suc is often used for sucrose in scientific literature. The name saccharose was coined in 1860 by the French chemist Marcellin Berthelot. Saccharose is an obsolete name for sugars in general, especially sucrose. In sucrose, the components glucose and fructose are linked via an ether bond between C1 on the glucosyl subunit and C2 on the fructosyl unit. The bond is called a glycosidic linkage. Glucose exists predominantly as two isomeric 'pyranoses' (α and β), but only one of these forms links to the fructose. Fructose itself exists as a mixture of 'furanoses', each of which having α and β isomers, but only one particular isomer links to the glucosyl unit. What is notable about sucrose is that, unlike most disaccharides, the glycosidic bond is formed between the reducing ends of both glucose and fructose, and not between the reducing end of one and the nonreducing end of the other. This linkage inhibits further bonding to other saccharide units. Since it contains no anomeric hydroxyl groups, it is classified as a non-reducing sugar. Sucrose crystallizes in the monoclinic space group P21 with room-temperature lattice parameters a = 1.08631 nm, b = 0.87044 nm, c = 0.77624 nm, β = 102.938°. The purity of sucrose is measured by polarimetry, through the rotation of plane-polarized light by a solution of sugar. The specific rotation at 20 °C using yellow 'sodium-D' light (589 nm) is +66.47°. Commercial samples of sugar are assayed using this parameter. Sucrose does not deteriorate at ambient conditions. Sucrose does not melt at high temperatures. Instead, it decomposes at 186 °C (367 °F) to form caramel. Like other carbohydrates, it combusts to carbon dioxide and water. Mixing sucrose with the oxidizer potassium nitrate produces the fuel known as rocket candy that is used to propel amateur rocket motors.