Sugar alcohol

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Erythritol is a sugar alcohol. It is 60–70% as sweet as sugar and almost noncaloric.

Sugar alcohols (also called polyhydric alcohols, polyalcohols, alditols or glycitols) are

hydroxyl group (−OH) attached to each carbon atom. They are white, water-soluble solids that can occur naturally or be produced industrially by hydrogenating sugars. Since they contain multiple (−OH) groups, they are classified as polyols
.

Sugar alcohols are used widely in the food industry as thickeners and sweeteners. In commercial foodstuffs, sugar alcohols are commonly used in place of table sugar (

artificial sweeteners, in order to offset their low sweetness. Xylitol and sorbitol are popular sugar alcohols in commercial foods.[1]

Structure

Sugar alcohols have the general formula HOCH2(CHOH)nCH2OH. In contrast, sugars have two fewer hydrogen atoms, for example, HOCH2(CHOH)nCHO or HOCH2(CHOH)n−1C(O)CH2OH. Like their parent sugars, sugar alcohols exist in diverse chain length. Most have five- or six-carbon chains, because they are derived respectively from pentoses (five-carbon sugars) and hexoses (six-carbon sugars), which are the more common sugars. They have one −OH group attached to each carbon. They are further differentiated by the relative orientation (stereochemistry) of these −OH groups. Unlike sugars, which tend to exist as rings, sugar alcohols do not, although they can be dehydrated to give cyclic ethers (e.g. sorbitan can be dehydrated to isosorbide).

Production

Sugar alcohols can be, and often are, produced from renewable resources. Particular feedstocks are starch, cellulose and hemicellulose; the main conversion technologies use H2 as the reagent: hydrogenolysis, i.e. the cleavage of C−O single bonds, converting polymers to smaller molecules, and hydrogenation of C=O double bonds, converting sugars to sugar alcohols.[2]

Sorbitol and mannitol

Mannitol is no longer obtained from natural sources; currently, sorbitol and mannitol are obtained by hydrogenation of sugars, using Raney nickel catalysts.[1] The conversion of glucose and mannose to sorbitol and mannitol is given as

HOCH2CH(OH)CH(OH)CH(OH)CH(OH)CHO + H2 → HOCH2CH(OH)CH(OH)CH(OH)CH(OH)CHHOH

Erythritol

Erythritol is obtained by the fermentation of glucose and sucrose.

Health effects

Sugar alcohols do not contribute to tooth decay; in fact, xylitol deters tooth decay.[3][4]

Sugar alcohols are absorbed at 50% of the rate of sugars, resulting in less of an effect on

blood sugar levels as measured by comparing their effect to sucrose using the glycemic index.[5][6]

Common sugar alcohols

Both

aldehyde group
is available for reduction.

Sugar alcohols as food additives

This table presents the relative sweetness and food energy of the most widely used sugar alcohols. Despite the variance in food energy content of sugar alcohols, the European Union's labeling requirements assign a blanket value of 2.4 kcal/g to all sugar alcohols.

Properties of sugar alcohols[additional citation(s) needed]
Name Relative sweetness (%)a Food energy (kcal/g)b Relative food energy (%)b Glycemic indexc Maximum non-laxative dose (g/kg body weight) Dental acidityd
Arabitol 70 0.2 5.0 ? ? ?
Erythritol 60–80 0.21 5.3 0 0.66–1.0+ None
Glycerol 60 4.3 108 3 ? ?
HSHsTooltip Hydrogenated starch hydrolysates 40–90 3.0 75 35 ? ?
Isomalt 45–65 2.0 50 2–9 0.3 ?
Lactitol 30–40 2.0 50 5–6 0.34 Minor
Maltitol 90 2.1 53 35–52 0.3 Minor
Mannitol 40–70 1.6 40 0 0.3 Minor
Sorbitol 40–70 2.6 65 9 0.17–0.24 Minor
Xylitol 100 2.4 60 12–13 0.3–0.42 None
Footnotes: a = Sucrose is 100%. b = Carbohydrates, including sugars like glucose, sucrose, and fructose, are ~4.0 kcal/g and 100%. c = Glucose is 100 and sucrose is 60–68. d = Sugars, like glucose, sucrose, and fructose, are high. References: [7][8][9][10][11][12]

Characteristics

As a group, sugar alcohols are not as sweet as sucrose, and they have slightly less food energy than sucrose. Their flavor is similar to 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

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

cooling sensation is due to the dissolution of the sugar alcohol being an endothermic (heat-absorbing) reaction,[1] one with a strong heat of solution.[13]

Absorption from the small intestine

Sugar alcohols are usually incompletely absorbed into the blood stream from the

diabetics and people on low-carbohydrate diets. As an exception, erythritol is actually absorbed in the small intestine and excreted unchanged through urine, so it contributes no calories even though it is rather sweet.[1][14]

Side effects

Like many other incompletely digestible substances, overconsumption of sugar alcohols can lead to bloating, diarrhea and flatulence because they are not fully 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.[14]

References

  1. ^
    ISBN 978-3-527-30673-2
    .
  2. PMID 22374680
    .
  3. ^
    PMID 8069881
    .
  4. ^
    S2CID 5442856
    .
  5. ^ Sue Milchovich, Barbara Dunn-Long: Diabetes Mellitus: A Practical Handbook, p. 79, 10th ed., Bull Publishing Company, 2011
  6. ^ Paula Ford-Martin, Ian Blumer: The Everything Diabetes Book, p. 124, 1st ed., Everything Books, 2004
  7. ISBN 978-0-12-811452-0
    .
  8. ISBN 978-0-12-814045-1
    .
  9. PMID 27840639
    .
  10. ^ Kathleen A. Meister; Marjorie E. Doyle (2009). Obesity and Food Technology. Am Cncl on Science, Health. pp. 14–. GGKEY:2Q64ACGKWRT.
  11. ISBN 978-1-118-37397-2
    .
  12. ISBN 978-1-4398-4614-8
    .
  13. S2CID 98559442
    .
  14. ^ a b "Eat Any Sugar Alcohol Lately?". Yale New Haven Health. 2005-03-10. Retrieved January 6, 2018.

External links

Wikimedia Commons has media related to Sugar alcohols.
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