Corn syrup is a food product derived from corn starch and either glucose or dextrose syrup. Corn syrup appears in a variety of confectionery treats, like lollipops and hard candies, caramels, toffees, jellies, chewing gum, hard creams, butterscotch, marshmallow and fondant, among others. Corn syrup affects candy texture, volume, flavor and color.
De-Crystalizing and Protein Interaction
Corn syrup replaces sugar in candy making. Its syrupy consistency means no crystals form in the candy. Instead, you have chewy or hard candy. Corn syrup is primarily glucose. This keeps sucrose, another type of sugar, from clumping and crystallizing. Corn syrup also keeps ice crystals from forming in ice cream. Corn syrup also reacts with proteins in candies containing milk, changing the confection's texture, color and flavor.
Texture and Sweetness
Corn syrup is used in a variety of candies to add either a thick, sticky consistency or a smooth, hard texture. Lollipops are made primarily of corn syrup, as are chewier candy bars. Confections and baked goods like pecan pie and certain fudge brownies get their body and thickness from corn syrup and eggs. Corn syrup also acts as a physical bonder for dry ingredients in candy and confections.
Corn Syrup vs. High Fructose Corn Syrup
Candy manufacturers sometimes use corn syrup for its culinary purposes. But it costs much less than sugar, as well, so it's typically used to cut costs. Food manufacturers may add fructose to corn syrup because it's sweeter than glucose, and they can save money by using less corn syrup. Many foods, including candy, contain high fructose corn syrup. Its health effects are being debated as of the publication of this article.
Various alternatives to corn syrup exist. You can try your hand at homemade cane sugar syrup, which is a bit less processed than commercial corn syrup. Rice syrup can prevent crystalizing, just like corn syrup. Its maltose and complex sugar molecules also keep other sugar molecules from bonding, but since it's less refined, it has a distinctive color and flavor that may be present in finished candy. Rice syrup is also made by fermentation, using enzymes derived from wheat, so it contains gluten. Other substitutes include molasses and maple syrup, both of which have different flavors and thickness.