Carbohydrates/sugar glucose

The word carbohydrate derives historically from the fact that glucose, the first simple carbohydrate to be obtained pure, has the molecular formula C6H,206 and was originally thought to be a "hydrate of carbon, C6(Tl20)6." This view was soon abandoned, but the name persisted. Today, the term carbohydrate is used to refer loosely to the broad class of polyhydroxvlated aldehydes and ketones commonly called sugars. Glucose, also known as dextrose in medical work, is the most familiar example. 

A monosaccharide is composed of one saccharide unit. Thus, it is the smallest molecule possible for a carbohydrate. A monosaccharide is often called a simple carbohydrate, or simple sugar. Glucose, seen in Figure 2.17, on the previous page, is one example of a monosaccharide. Other monosaccharides include fructose, galactose, and mannose. 

Fermentation—A biochemical reaction involving enzymes that breaks down complex carbohydrates and simple sugar (glucose), usually producing carbon dioxide and ethanol or an acid. 

A doctor might also use a chemical reaction to test a patients blood glucose (sugar) level. Remember that during digestion, carbohydrates are broken down into the simplest sugar, glucose. 

Failure to ingest adequate amounts of carbohydrates resulted in sweating, blurred vision, tremors, headaches, and confusion. Smarter athletes monitored their blood sugar (glucose) levels with test strips or metes. 

Studies by electron-spin resonance spectroscopy showed that the reaction of hydroxy radicals with carbohydrates produces new radicals via hydrogen abstraction from a C-H group. When such carbohydrates as glucose are substrates, the H abstraction from a C-H bond is relatively nonselective, and all six possible radicals can be formed. The fate of these radicals is strongly influenced by the type of starting sugar and by the species present in the reaction medium. All of these aspects have been discussed in the review article by Sheldon et al.69... 

Carbohydrates Sugars and other carbohydrates most commonly exist as cyclic acetals and hemiacetals. For example, glucose is a six-carbon sugar that is most stable as a hemiacetal. Lactose is a disaccharide (composed of two sugar units) that has one acetal and one hemiacetal. We discuss the structures of carbohydrates in detail in Chapter 23. 

Ethanol fermentation can be conducted on any carbohydrate-rich substrate. Molasses, which is the waste mother liquor that remains after the crystallization of sucrose in sugar mill operations, is widely used. Blackstrap molasses contains 35-40 percent sucrose and 15-20 percent invert sugars (glucose and fructose). High-test molasses contains 22-27 percent sucrose and 50-55 percent invert sugars. Most of the blackstrap molasses do not... 

Caramel in this context means a brown colour that is produced either traditionally by heating sugar or as a very intense product that is made by heating carbohydrate, usually glucose syrup, with ammonia. Caramel colour is the product of the Maillard reaction, i.e. the reaction of a reducing sugar with an amino group. Chemically the colour is a melanoidin - these substances are extremely stable and can be used in any type of confectionery. 

Liquorice is a slightly unusual example of a starch gel instead of separating the starch, wheat flour is used directly. It is also a product where brown sugars and treacle are used. Liquorice paste is typically made from treacle, wheat flour, liquorice extract and caramel. Caramel in this context means the brown colour produced from sugar and not a form of toffee. Industrial caramel is made by the action of ammonium hydroxide on a carbohydrate, typically glucose syrup. The resulting product is not well defined chemically, and for this reason its use is recommended to be limited to 0.2% maximum. 

Lactose, a carbohydrate formed from two simple sugars, glucose and galactose, is the principal sugar in dairy products. Many individuals, mainly of Asian and African descent, lack adequate amounts of the enzyme necessary to digest and absorb lactose. This condition, lactose intolerance, is associated with abdominal cramping and recurrent diarrhea, and is precipitated by the ingestion of milk and dairy products. In Chapter 27, we learn about the structure, synthesis, and properties of carbohydrates like lactose. 

Carbohydrates are sugars—glucose, fructose, galactose. The familiar sucrose is a disaccharide two saccharides linked together. When more than two saccharides are linked together, the result is a polysaccharide. Long-chain polysaccharides form the essential materials of starch, cellulose, and glycogen. 

Cellulose. Carbohydrate pol)rmer of the simple sugar glucose. It is found in the cell walls of plants and green algae, as well as dinoflagellates. Cellulose is the most abundant compound on earth that is manufactured by living things. 

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