It is made from corn starch, potato starch, or wheat starch, which is broken down into small units such as glucose, dextrin, malto-dextrin, and polydextrin, by amylase enzymes in a process called hydrolyzing.
Hydrolyzing breaks the bond between two glucose molecules by adding an OH to one glucose, and a hydrogen to the other. The H and OH come from splitting water, hence the name hydrolyze, which means to break apart using water.
After the starch is broken into little pieces of glucose and short glucose chains, the pieces are converted from sugars to sugar alcohols by adding two hydrogens, using heat and pressure. The addition of hydrogen to a molecule is called hydrogenation.
If the starch is completely hydrolyzed, so that there are only single glucose molecules, then after hydrogenation the result is sorbitol. If the starch is not completely hydolyzed, then a mixture of sorbitol, maltitol, and longer chain hydrogenated saccharides (such as maltitriitol) is produced. When there is no single dominant polyol in the mix, the generic name hydrogenated starch hydrosylate is used.
If more than half of the polyols in the mixture are of one type, then the mixture is called "sorbitol syrup", or "maltitol syrup", etc.
Hydrogenated starch hydrosylate is used in low calorie candies, and in many foods as both a sweetener and as a humectant (moisture retaining ingredient).
As a crystallization modifier, it can prevent syrups from forming crystals of sugar. It is used to add body and viscosity to mixtures, and can protect against damage from freezing and drying.
Hydrogenated starch hydrosylate is also used as a carrier for enzymes, colors, or flavors.