Sugar alcohol

A sugar alcohol (also known as a polyol, polyhydric alcohol, or polyalcohol) is a hydrogenated form of carbohydrate, whose carbonyl group (aldehyde or ketone, reducing sugar) has been reduced to a primary or secondary hydroxyl group (hence the alcohol). Sugar alcohols have the general formula H(HCHO)_n+1H, whereas sugars have H(HCHO)_nHCO. In commercial foodstuffs sugar alcohols are commonly used in place of table sugar (sucrose), often in combination with high intensity artificial sweeteners to counter the low sweetness. Of these, xylitol is perhaps the most popular due to its similarity to sucrose in appearance and sweetness. Sugar alcohols do not contribute to tooth decay.

Some common sugar alcohols:

Both disaccharides and monosaccharides can form sugar alcohols; however, sugar alcohols derived from disaccharides (e.g. maltitol and lactitol) are not entirely hydrogenated because only one aldehyde group is available for reduction.

The simplest sugar alcohol, ethylene glycol, is the sweet but notoriously toxic chemical used in antifreeze. The higher sugar alcohols are for the most part nontoxic.

Sugar alcohols as food additives

As a group, sugar alcohols are not as sweet as sucrose, and they contain fewer calories than sucrose. Their flavor is like sucrose, and they can be used to mask the unpleasant aftertastes of some high intensity sweeteners. Sugar alcohols are not metabolized by oral bacteria, and so they do not contribute to tooth decay.^{[citation needed]} They do not brown or caramelize when heated.

In addition to their sweetness, some sugar alcohols can produce a noticeable cooling sensation in the mouth when highly concentrated, for instance in sugar-free hard candy or chewing gum. This happens, for example, with the crystalline phase of sorbitol, erythritol, xylitol, mannitol, lactitol and maltitol. The cooling sensation is due to the dissolving of the sugar alcohol being an endothermic (heat-absorbing) reaction, one with a strong heat of solution. ^[1]

Sugar alcohols are usually incompletely absorbed into the blood stream from the small intestines which generally results in a smaller change in blood glucose than "regular" sugar (sucrose). This property makes them popular sweeteners among diabetics and people on low-carbohydrate diets. However, like many other incompletely digestible substances, overconsumption of sugar alcohols can lead to bloating, diarrhea and flatulence because they are not absorbed in the small intestine. Some individuals experience such symptoms even in a single-serving quantity. With continued use, most people develop a degree of tolerance to sugar alcohols and no longer experience these symptoms. As an exception, erythritol is actually absorbed in the small intestine and excreted unchanged through urine, so it has no side effects at typical levels of consumption.

The table to the right presents the relative sweetness and measured caloric content of the most widely-used sugar alcohols. Despite the variance in caloric content of sugar alcohols, EU labeling requirements assign a blanket value of 2.4 kcal/g to all sugar alcohols.

People who have undergone gastric bypass surgery, specifically Roux-en-Y (RGB), should be careful not to eat too many sugar alcohols as doing so, with the exception of Erythritol, can lead to "dumping".^{[citation needed]}

References

External links

• Alcohol Fact Sheet - An International Food Information Council publication