Details:

Sorbitol, also known as glucitol, is a sugar alcohol with a sweet taste which the human body metabolizes slowly. It can be obtained by reduction of glucose, changing the aldehyde group to a hydroxyl group. Most sorbitol is white hygroscopic powder or crystalline powder, flake or granular, odourless. According to the different crystallization conditions, its melting point changes within 88 ~ 102 ℃. It dissolves easily in water, and is slightly soluble in ethanol and acetic acid. It has a sweet taste of cool and refreshing, about half sweetness of sucrose, and close calorific value to sucrose. 

It is made from corn syrup, but it is also found in apples, pears, peaches, and prunes. It is converted to fructose by Sorbitol-6-phosphate 2-dehydrogenase. Sorbitol is an isomer of mannitol, another sugar alcohol; the two differ only in the orientation of the hydroxyl group on carbon 2. While similar, the two sugar alcohols have very different sources in nature, melting points, and uses.

Application:

1. Sweetener

Sorbitol is a sugar substitute. It may be listed under the inactive ingredients listed for some foods and products. Its INS number and E number is 420. Sorbitol has approximately 60% the sweetness of sucrose (table sugar).

Sorbitol is referred to as a nutritive sweetener because it provides dietary energy: 2.6 kilocalories (11 kilojoules) per gram versus the average 4 kilocalories (17 kilojoules) for carbohydrates. It is often used in diet foods (including diet drinks and ice cream), mints, cough syrups, and sugar-free chewing gum.

It also occurs naturally in many stone fruits and berries from trees of the genus Sorbus.

2. Laxative

Sorbitol can be used as a non-stimulant laxative via an oral suspension or enema. As with other sugar alcohols, gastrointestinal distress may result when food products that contain sorbitol are consumed. Sorbitol exerts its laxative effect by drawing water into the large intestine, thereby stimulating bowel movements. Sorbitol has been determined safe for use by the elderly, although it is not recommended without consultation with a clinician. Sorbitol is found in some dried fruits and may contribute to the laxative effects of prunes. Sorbitol was discovered initially in the fresh juice of mountain ash (Sorbus aucuparia) berries in 1872. It is found in the fruits of apples, plums, pears, cherries, dates, peaches, and apricots.

3. Medical applications

Sorbitol is used in bacterial culture media to distinguish the pathogenic Escherichia coli O157:H7 from most other strains of E. coli, as it is usually incapable of fermenting sorbitol, but 93% of known E. coli strains are capable of doing so.

A treatment using sorbitol and ion-exchange resin sodium polystyrene sulfonate (tradename Kayexalate), helps remove excess potassium ions when in a hyperkalaemic state. The resin exchanges sodium ions for potassium ions in the bowel, while sorbitol helps to eliminate it. In 2010 the U.S. FDA issued a warning of increased risk for GI necrosis with this combination.

Sorbitol is also used in the manufacture of Softgels to store single doses of liquid medicines like tablets are used to control the dosage of solids.

4. Health care, food, and cosmetic uses

Sorbitol often is used in modern cosmetics as a humectant and thickener. Sorbitol often is used in mouthwash and toothpaste. Some transparent gels can be made only with sorbitol, as it has a refractive index sufficiently high for transparent formulations. It is also used frequently in "sugar free" chewing gum.

Sorbitol is used as a cryoprotectant additive (mixed with sucrose and sodium polyphosphates) in the manufacture of surimi, a highly refined fish paste most commonly produced from Alaska pollock (Theragra chalcogramma).[citation needed] It is also used as a humectant in some cigarettes.

Sorbitol sometimes is used as a sweetener and humectant in cookies and other foods that are not identified as "dietary" items.

5. Miscellaneous uses

A mixture of sorbitol and potassium nitrate has found some success as an amateur solid rocket fuel.

Sorbitol is identified as a potential key chemical intermediate for production of fuels from biomass resources. Carbohydrate fractions in biomass such as cellulose undergo sequential hydrolysis and hydrogenation in the presence of metal catalysts to produce sorbitol. Complete reduction of sorbitol opens the way to alkanes, such as hexane, which can be used as a biofuel. Hydrogen required for this reaction can be produced by aqueous phase reforming of sorbitol.

The above chemical reaction is exothermic; 1.5 moles of sorbitol generate approximately 1 mole of hexane. When hydrogen is co-fed, no carbon dioxide is produced.

It is also added after electroporation of yeasts in transformation protocols, allowing the cells to recover by raising the osmolarity of the medium.