Maltitol syrup is made from starch, most commonly sourced from corn, wheat, or potatoes. The starch undergoes a multi-step industrial process that breaks it down into maltose (a simple sugar) and then chemically converts that maltose into maltitol, a sugar alcohol. The result is a thick, sweet syrup used widely in sugar-free and reduced-calorie foods.
The Starting Material: Starch
The production of maltitol syrup begins with starch extracted from cereal crops. Corn is the most common source globally, though wheat and potato starch are also used depending on the region and manufacturer. These crops are chosen because they yield large quantities of high-purity starch at relatively low cost.
Small amounts of maltitol do occur naturally in foods like roasted malt and chicory leaves, but nowhere near enough for commercial use. Virtually all the maltitol syrup you encounter on ingredient labels is manufactured from these plant starches through industrial processing.
How Starch Becomes Maltitol Syrup
Turning starch into maltitol syrup involves two main stages. First, the starch is broken down into maltose using enzymes. Starch molecules are long chains of glucose units, and specific enzymes snip those chains into pairs of glucose molecules, which is what maltose is. This step is similar to what happens in your body when you digest starchy foods, just faster and more controlled in an industrial setting.
The second stage is called hydrogenation. The maltose syrup is exposed to hydrogen gas under high pressure in the presence of a metal catalyst (typically nickel). This reaction adds hydrogen atoms to the maltose molecule, converting it into maltitol. The process is conceptually the same as what’s used to turn liquid vegetable oils into solid fats, though the end product here is a sugar alcohol rather than a fat. After hydrogenation, the syrup is purified, filtered, and concentrated to the desired thickness.
What Makes It a Sugar Alcohol
Maltitol belongs to a family of sweeteners called polyols, commonly known as sugar alcohols. Despite the name, they contain no ethanol and won’t make you intoxicated. The “alcohol” refers to a specific arrangement of atoms in the molecule. Other sugar alcohols you may recognize include xylitol, sorbitol, and erythritol.
What sets sugar alcohols apart from regular sugars is how your body handles them. They’re only partially absorbed in the small intestine, which means they deliver fewer calories. Maltitol provides about 2.1 calories per gram, roughly half the 4 calories per gram you get from regular sugar. That partial absorption is also why sugar alcohols, maltitol included, can cause digestive discomfort in larger amounts. The unabsorbed portion moves into the large intestine, where gut bacteria ferment it, potentially producing gas, bloating, or a laxative effect.
Maltitol Syrup vs. Powdered Maltitol
You’ll find maltitol in two forms on ingredient labels: maltitol syrup and crystalline (powdered) maltitol. They come from the same raw materials and the same basic process, but they differ in purity and physical form. Crystalline maltitol is the dried, purified version with a very high maltitol concentration, typically above 98%. Maltitol syrup, on the other hand, contains maltitol along with other hydrogenated sugars like sorbitol and longer-chain polyols. The exact maltitol content in the syrup varies by grade but is generally lower than the crystalline form.
This matters for blood sugar. Crystalline maltitol has a glycemic index around 35, which is meaningfully lower than table sugar’s 65. Maltitol syrup, however, scores higher on the glycemic index, roughly in the range of 50 to 55, because of those additional sugar components. If you’re monitoring blood sugar closely, the syrup form will have a more noticeable effect than the powder.
Why Manufacturers Use the Syrup Form
Food manufacturers often prefer maltitol syrup over the crystalline powder for practical reasons. The liquid form blends easily into candy fillings, chocolate coatings, baked goods, and ice cream without the need for additional dissolving steps. It also acts as a humectant, meaning it holds onto moisture and keeps products soft and chewy over time. In hard candies, it helps prevent unwanted crystallization that would ruin the texture.
Maltitol syrup provides about 75% to 90% of the sweetness of sugar, which is higher than most other sugar alcohols. That makes it popular in “sugar-free” products where manufacturers want to match the taste and mouthfeel of sugar as closely as possible without using it. You’ll commonly see it in sugar-free chocolate, protein bars, cough syrups, and chewing gum.
Corn Allergen and Dietary Considerations
Because maltitol syrup is most often derived from corn starch, people with corn allergies sometimes wonder whether it’s safe. The extensive processing involved in breaking down starch and hydrogenating it typically removes the proteins responsible for allergic reactions. Most allergists consider highly refined corn-derived ingredients safe for corn-allergic individuals, but reactions in very sensitive people aren’t impossible. If you have a confirmed corn allergy, checking with the manufacturer about the starch source is a reasonable step.
For people following a ketogenic or very low-carb diet, maltitol syrup is one of the less ideal sugar alcohols. Its relatively high glycemic index compared to alternatives like erythritol or allulose means it still raises blood sugar to a moderate degree. Many net-carb calculations subtract sugar alcohols entirely, but with maltitol, a significant portion is absorbed and metabolized, so that subtraction overstates the benefit.