About Corn Syrup
There is no such thing as a natural corn syrup pressed directly from corn kernels. Instead, the pulpy middle layer called cornstarch is first separated from the outer husk and the inner germ layers. The cornstarch is then stored in giant vats, where natural enzymes are added to break it down into glucose. It is these sugars that are heated and turned into what is called corn syrup.
Corn syrup is almost exactly as sweet as the granulated sugar it often replaces in recipes. It can be naturally light in color, which is often used in candy making, or darker, which is usually used for general baking purposes. The light form of corn syrup may have vanilla flavoring added, while the dark corn syrup has a stronger natural flavor.
The advantage of corn syrup over sugar is its resistance to crystallization. A candy lollipop made with corn syrup will retain its smooth texture, while a similar treat made from pure sugar may turn into a hardened rock candy. Corn syrup also prohibits crystal formation when sugar is added to a cake or fudge mixture.
Light and dark corn syrup both have a balance of dextrose, fructose, malt and glucose to keep them chemically stable, although this sweetener does have a limited shelf life compared to others