High fructose corn syrup is made by milling cornstarch from corn, combining the cornstarch with water, and adding an enzyme to shorten the starch's glucose chain. A second enzyme is added to produce glucose, and a third is added to convert some of the glucose to fructose.
The first enzyme in high fructose corn syrup is alpha-amylase. This protein enzyme breaks cornstarch's sugar chains into smaller chains called oligosaccharides. The second enzyme, glucoamylase, turns the oligosaccharides into glucose, a simple sugar. Once glucoamylase is added, the resulting mixture becomes regular corn syrup. To make high fructose corn syrup, a third and final enzyme is added to convert glucose into a mixture that is 42 percent fructose and 50 to 52 percent glucose. This type of high fructose corn syrup is called HFCS 42 because of its fructose ratio.
High fructose corn syrup is widely used throughout America because it is less-expensive than sugar. HFCS 42 is almost as sweet as table sugar, and is used in baked goods, cereals and other processed foods. HFCS 55, which contains 55 percent fructose and 42 percent glucose, is mainly used in soft drinks.
High fructose corn syrup was introduced in 1957, but was not mass produced until the late 1960s. The product costs twice as much in America and Canada compared to the rest of the world because of domestic sugar quotas and sugar import tariffs imposed in 1977. One bushel of corn weighs 70 pounds and produces about 32 pounds of high fructose corn syrup.