Isomalt

What is isomalt?

Isomalt is a mixture of two sugar alcohols: gluco-mannitol (GPM) and gluco-sorbitol (GPS) (Picture 1) ^[1]. It is artificially produced from sucrose or, more precisely, from its product isomaltulose by adding certain enzymes and hydrogen ^[1,2-p.177].

Isomalt Structure

Picture 1. Isomalt is a mixture of
1-O-α-D-glucopyranosido-D-mannitol-dihydrate (1,1-GPM-dihydrate) and
6-O-α-D-glucopyranosido-D-sorbitol (1,6-GPS).

Nutrition Facts

Calories per gram = 2
Glycemic index (GI) = 9
Sweetness, relative to sucrose = 55%
Net carbs = zero

Isomalt Uses

Isomalt is used as a sweetener, bulking, anti-caking and glazing agent in low-calorie candies, toffees, chewing gum, chocolates, ice creams, baked goods, ready-to-eat cereals, fruit spreads, frozen and smoked fish and meat, jams, preserves, infant formulas, cough syrups, multivitamin/mineral supplements, pan-coated tablets, lozenges ^[1]. On the food labels in the European Union isomalt is labeled as E number E953 ^[3].

Isomalt Digestion and Metabolism

Only about 10% of the ingested isomalt is digested to glucose, sorbitol and mannitol in the small intestine, the rest passes to the large intestine where it is broken down (fermented) by the beneficial bacteria into gases and short chain fatty acids (SCFAs), which are partly absorbed in the colon and partly used as a food for the bacteria ^[1,2-p.184].

Nutrition Facts and Calories

Isomalt can provide 2 kilocalories per gram, which is 50% less than sucrose ^[2-p.59].

Possible Isomalt Benefits

Tooth decay. Isomalt does not promote tooth decay ^{[1, 2-p.185]}.

Low glycemic index. GI of isomalt = 9. Isomalt only slightly raises blood glucose and insulin levels after ingestion and does not trigger reactive hypoglycemia after the meals ^[2-p.184].

Isomalt Safety and Side Effects

Currently (y. 2014), isomalt is not Generally Recognized As Safe (GRAS) by the US Food and Drug Administration ( FDA), but the U.S. food manufacturers may use it since the FDA has accepted petition seeking this approval ^[4]. Isomalt has “Acceptable Daily Intake (ADI) not specified” status by The Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA), which is the safest category ^[5]. Isomalt is approved in the U.S., Australia, the European Union, Russia, China, Japan, India and many other countries ^[2-p.203].

Isomalt attracts water from the intestinal wall, so it can cause diarrhea (an osmotic effect) if consumed in excess. Most healthy people can probably tolerate at least 50 grams isomalt per day ^[2-p.185]. For example, 3.5 oz (100 g) chocolate can contain about 45 grams isomalt and one oz (28 g) of fruit spread about 10 grams ^{[2-pp.192,199]}.

Allergy to isomalt products may be possible.

Isomalt and Cooking

Physical properties:

A white crystalline powder without odor ^[1]
55% as sweet as sucrose ^[1]; slowly dissolves in the mouth and has only a slight cooling effect ^[2-p.182]
Low hygroscopicity – does not readily absorbs moisture from the air at relative humidity 85% ^[2-p.183]
Solubility in water at 77 °F (25° C) = 25 g/100 g solution ^[2-p.158]; poorly soluble in ethanol ^[5]
Melting point = 293-302° F (145-150° C) ^[2-p.158]
Decomposes at temperatures higher than 320° F (160° C) ^[2-p.158]
According to one of the producers, isomalt will not caramelize or undergo the Maillard browning reaction with amino acids ^[2-p.199].