Product Code Database
Sorbitol (), less commonly known as glucitol (), is a sugar alcohol with a sweet taste which the human body metabolizes slowly. It can be obtained by Redox of glucose, which changes the converted aldehyde group (−CHO) to a primary alcohol group (−CH2OH). Most sorbitol is made from potato starch, but it is also found in nature, for example 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 carbon2.Kearsley, M. W.; Deis, R. C. Sorbitol and Mannitol. In Sweeteners and Sugar Alternatives in Food Technology; Ames: Oxford, 2006; pp 249-249-261. While similar, the two sugar alcohols have very different sources in nature, , and uses.
As an over-the-counter drug, sorbitol is used as a laxative to treat constipation.
The mechanism involves a tyrosine residue in the active site of aldehyde reductase. The hydrogen atom on NADH is transferred to the electrophilic aldehyde carbon atom; electrons on the aldehyde carbon-oxygen double bond are transferred to the oxygen that abstracts the proton on tyrosine side chain to form the hydroxyl group. The role of aldehyde reductase tyrosine phenol group is to serve as a general acid to provide proton to the reduced aldehyde oxygen on glucose.
Glucose reduction is not the major glucose metabolism pathway in a normal human body, where the Blood sugar is in the normal range. However, in diabetic patients whose blood glucose level is high, up to 1/3 of their glucose could go through the glucose reduction pathway. This will consume NADH and eventually leads to cell damage.
Sorbitol is referred to as a nutritive sweetener because it provides some dietary energy. It is partly absorbed from the small intestine and metabolized in the body, and partly fermented in the large intestine. The fermentation produces short-chain fatty acids, acetic acid, propionic acid, and butyric acid, which are mostly absorbed and provide energy, but also carbon dioxide, methane, and hydrogen which do not provide energy. Even though the heat of combustion of sorbitol is higher than that of glucose (having two extra hydrogen atoms), the net energy contribution is between 2.5 and 3.4 per gram, versus the approximately 4 kilocalories (17 kilojoules) for carbohydrates. It is often used in (including diet drinks and ice cream), mints, , and sugar-free chewing gum. (2025). 9781111425647, Brooks/Cole. ISBN 9781111425647 Most bacteria cannot use sorbitol for energy, but it can be slowly fermented in the mouth by Streptococcus mutans, a bacterium that causes tooth decay. In contrast, many other sugar alcohols such as isomalt and xylitol are considered non-acidogenic.
It also occurs naturally in many drupe and berries from trees of the genus Sorbus.
Sorbitol is commonly used orally as a one-time dose of 70% solution. It may also be used as a one-time rectum enema.
A treatment for Hyperkalemia (elevated blood potassium) uses sorbitol and the ion-exchange resin sodium polystyrene sulfonate (tradename Kayexalate). 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 gastrointestinal necrosis with this combination.
Sorbitol is also used in the manufacture of softgel to store single doses of liquid medicines.
Sorbitol is used as a cryoprotectant additive (mixed with sucrose and sodium poly) in the manufacture of surimi, a processed fish paste. It is also used as a humectant in some .
Beyond its use as a sugar substitute in reduced-sugar foods, sorbitol is also used as a humectant in cookies and low-moisture foods like peanut butter and fruit preserves.
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 , such as hexane, which can be used as a biofuel. Hydrogen required for this reaction can be produced by aqueous phase catalytic reforming of sorbitol.
The above chemical reaction is exothermic, and 1.5 moles of sorbitol generate approximately 1 mole of hexane. When hydrogen is co-fed, no carbon dioxide is produced.
Sorbitol based polyols are used in the production of polyurethane foam for the construction industry.
It is also added after electroporation of yeasts in transformation protocols, allowing the cells to recover by raising the osmolarity of the medium.
Sorbitol is fermented in the colon and produces short-chain fatty acids, which are beneficial to overall colon health.
Medical applications
Laxative
As is the case with other , foods containing sorbitol can cause gastrointestinal distress. Sorbitol can be used as a laxative when taken orally or as an enema. Sorbitol works as a laxative by drawing water into the large intestine, stimulating bowel movements. Sorbitol has been determined safe for use by the elderly, although it is not recommended without the advice of a physician.
Other medical applications
Sorbitol is used in bacterial culture media to distinguish the pathogenic from most other strains of Escherichia coli, because it is usually unable to ferment sorbitol, unlike 93% of known E. coli strains.
Health care, food, and cosmetic uses
Sorbitol often is used in modern cosmetics as a humectant and thickener. It is also used in mouthwash and toothpaste. Some transparent can be made only with sorbitol, because of its high refractive index.
(2025). 9780203495728, CRC Press. ISBN 9780203495728 In baking, it is also valuable because it acts as a plasticizer, and slows down the staling process.
Miscellaneous uses
A mixture of sorbitol and potassium nitrate has found some success as an amateur rocketry solid rocket fuel. It has similar performance to sucrose-based rocket candy, but is easier to cast, less hygroscopic and does not caramelization.
Medical importance
Aldose reductase is the first enzyme in the Polyol pathway responsible for the reduction of glucose to sorbitol, as well as the reduction of galactose to galactitol. Too much sorbitol trapped in retinal cells, the cells of the lens, and the Schwann cells that peripheral nerves, is a frequent result of long-term hyperglycemia that accompanies poorly controlled diabetes. This can damage these cells, leading to retinopathy, and peripheral neuropathy, respectively.
Potential adverse effects
Sorbitol may cause allergic reactions in some people. Common side effects from use as a laxative are Cramp, vomiting, diarrhea or rectal bleeding.
Compendial status
See also
External links
|
|
