Erythritol

Erythritol ((2R,3S)-butane-1,2,3,4-tetraol) is a natural sugar alcohol (a type of sugar substitute) which has been approved for use in the United States and throughout much of the world. It occurs naturally in fruits and fermented foods. At industrial level, it is produced from glucose by fermentation with a yeast, Moniliella pollinis. It is 60-70% as sweet as table sugar yet it is almost non-caloric, does not affect blood sugar, does not cause tooth decay, and is absorbed by the body, therefore unlikely to cause gastric side effects unlike other sugar alcohols. Under U.S. Food and Drug Administration (FDA) labeling requirements, it has a caloric value of 0.2 calories per gram (95% less than sugar and other carbohydrates), but some countries like Japan label it at 0 calories. European legislation actually considers it at 2.4 kcal/g but pending discussion will certainly achieve a 0 kcal/g caloric value by 2009.

Erythritol and human digestion
In the body, erythritol is absorbed into the bloodstream in the small intestine, and then for the most part excreted unchanged in the urine. Because erythritol is normally absorbed before it enters the large intestine, it does not normally cause laxative effects as are often experienced after over-consumption of other sugar alcohols (such as xylitol and maltitol) and most people will consume erythritol with no side effects. This is a unique characteristic, as other sugar alcohols are not absorbed directly by the body in this manner, and consequently are more prone to causing gastric distress.

As a whole, erythritol is generally free of side-effects in regular use, but if consumed in very extreme quantities (sometimes encouraged by its almost non-caloric nature), effectively consuming it faster than one's body can absorb it, a laxative effect may result. The laxative response does not begin until you cross your body's natural absorption threshold, which is the point at which you have ingested more erythritol than is found in reasonable servings of food products and is usually a larger amount than most people will eat in a single sitting. Erythritol, when compared with other sugar alcohols, is also much more difficult for intestinal bacteria to digest, so it is unlikely to cause gas or bloating, unlike maltitol, sorbitol, or lactitol.

Heat of solution
Erythritol has a strong cooling effect (positive heat of solution ) when it dissolves in water, often combined with the cooling effect of mint flavors, but proves distracting with more subtle flavors and textures. The cooling effect is only present when erythritol is not already dissolved in water, a situation that might be experienced in an erythritol-sweetened frosting, chocolate bar, chewing gum, or hard candy. When combined with solid fats, such as coconut oil, cocoa butter or cow's butter, the cooling effect tends to accentuate the waxy characteristics of the fat in a generally undesirable manner. This is particularly pronounced in chocolate bars made with erythritol. The cooling effect of erythritol is very similar to that of xylitol and among the strongest cooling effects of all sugar alcohols.

Blending for sugar-like properties
Beyond high intensity sweeteners, erythritol is often paired with other bulky ingredients that exhibit sugar-like characteristics to better mimic the texture and mouthfeel of sucrose. Often these other ingredients are responsible for the gastric side effects blamed on erythritol. The cooling effect of erythritol is rarely desired, so hence other ingredients are chosen to dilute or even negate that effect. Erythritol also has a propensity to crystallize and is not as soluble as sucrose, so ingredients may also be chosen to help negate this disadvantage. Furthermore, erythritol is non-hygroscopic, meaning it does not attract moisture, which can lead to products, particularly baked goods, drying out if another hygroscopic ingredient is not used in the formulation.

Very commonly, inulin is combined with erythritol, due to inulin offering a complementary negative heat of solution (warming effect when dissolved that helps cancel erythritol's cooling effect) and non-crystallizing properties. Unfortunately, inulin has a propensity to cause gas and bloating when consumed in moderate to large quantities, particularly in individuals unaccustomed to it. Other sugar alcohols are sometimes utilized with erythritol, particularly isomalt due to its minimally positive heat of solution, and glycerin which has a negative heat of solution, moderate hygroscopicity, and non-crystallizing liquid form.

Erythritol and bacteria
Erythritol has been certified as tooth-friendly. The sugar alcohol cannot be metabolized by oral bacteria, and so does not contribute to tooth decay. Interestingly, erythritol exhibits some, but not all, of the tendencies to "starve" harmful bacteria like xylitol does. Unlike xylitol, erythritol is actually absorbed into the bloodstream after consumption but before excretion. However, it is not clear at present if the effect of starving harmful bacteria occurs systemically.