How Does Isomaltose Factor into the Sugar Declaration on the Nutritional Label?
What Is Isomaltose?
Isomaltose is a disaccharide composed of two glucose molecules linked by an α-(1→6) glycosidic bond. It occurs naturally in foods such as honey and can also be present in foods and beverages made with malted or processed grains, where it forms during the enzymatic breakdown of starch. Examples include beer, soy sauce, and miso. In humans, isomaltose is digested in the small intestine by the sucrase-isomaltase enzyme.1 Studies in model organisms suggest it may be digested more slowly supporting a lower glycemic index,2 but it provides the same energy value as glucose at 4 kcal/g as it is fully digested.
Why It Matters for Sugar Labeling
The U.S. Food and Drug Administration (FDA) defines total sugars on the Nutrition Facts label as all free monosaccharides and disaccharides, with examples including glucose, fructose, lactose, and sucrose.3 Standard sugar profile methods typically measure those sugars along with galactose and maltose. Many other mono and disaccharides exist, but they are typically present only at trace levels. However, isomaltose may be more relevant in certain foods and ingredients particularly those derived from malted grains, fermented products, or starch hydrolysis processes. Depending on the product specification, significant free isomaltose may be present in Isomaltooligosaccharides (IMO). IMO is slowly digested and considered a prebiotic dietary fiber in some countries like Canada. As an alternative carbohydrate in typically low sugar products, it is important to understand that it may be contributing sugar, even though a standard sugar profile does not measure it.
This can create a blind spot for food and beverage brands and manufacturers with traditional sugar testing. If isomaltose is present but not measured, total sugar values may be understated which may impact label accuracy, claims, and compliance decisions.
For products where isomaltose could meaningfully affect the declared sugar value, including it in the analysis can help avoid underreporting total sugars. Especially in cases when the result may influence whether the product meets a Sugar Free or No Added Sugar claim (<0.5 g per serving threshold for labeling).
How Eurofins Can Help
Standard sugar analyses don’t always tell the full story, especially when isomaltose is present. Eurofins Food Chemistry Testing Madison, Inc. addresses this gap by measuring isomaltose as part of your product’s sugar profile using our AOAC 2018.16-based method. The result: more complete data, reduced risk of underreporting, and stronger support for labeling claims that can withstand scrutiny.
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