There was a time when manufacturers of processed foods used common table sugar, or sucrose, as their default sweetener. In the 1970s, however, Japanese scientists discovered a process which could convert cornstarch into an alternative sweetener called high fructose corn syrup. This type of sweetener contains 55% fructose and 45% glucose, which makes it virtually as sweet as sucrose or natural honey. When imported sugar became prohibitively expensive, many processed food and beverage manufacturers began using high fructose corn syrup exclusively.
Today, high fructose corn syrup has prevalent use in the United States. It has replaced pure sugar as the main sweetener in most carbonated beverages, including Coca Cola and Pepsi products. It can also be found in cake mixes, cookies, sauces, breakfast cereals and commercial baked goods. Some companies still use pure cane sugar when feasible, but because the US government subsidizes much of the corn industry, high fructose corn syrup is often a cheaper alternative. In the United States, it's processed in specialized factories.
Production is a bit complex. Cornstarch originally contains very long chemical chains of pure glucose, which must first be broken down into shorter chains called polysaccharides. This is accomplished by adding an enzyme called alpha-amylase, which is derived from a bacteria.
Once the cornstarch has been broken down, a second enzyme called glucoamylase is added to the vat. Glucoamylase is derived from a fungus called Aspergillus. The continued fermentation converts the slurry into almost pure glucose.
The third processing step is the most expensive. An enzyme called glucose-isomerase is stored in tall columns and the glucose slurry is poured across the top of those columns. The enzyme converts the pure glucose into a combination of fructose and glucose, but not at the final percentages desired. A process called liquid chromatography essentially distills the syrup into 90% fructose. This concentrated fructose product is then blended back into the original mix to create the final 55% fructose, 45% glucose product also known as high fructose corn syrup.
Amazingly enough, all of this processing does not significantly add to the cost of production. Partially because of high tariffs placed on imported cane sugar, high fructose corn syrup is still cheaper than sugar and can be inexpensively shipped in tanker trucks.
Not everyone, however, is sold on the benefits of high fructose corn syrup. Some health experts express concern over the level of genetic modification and processing used to create the finished product. Even though consumers associate fructose with natural fruit sugars, the concentration of fructose found in high fructose corn syrup is not necessarily natural. Diabetics and others who must monitor their blood sugar levels may not get accurate glycemic readings after ingesting fructose. Others point out the association with processed foods and obesity.
There are those who say that products made exclusively with high fructose corn syrup do not taste as good as those made with pure cane sugar or other sweeteners. Chemically, it is exactly as sweet as cane sugar or honey, but a number of consumers seem to prefer the use of more natural sweeteners. If avoiding is an issue, one might want to consider shopping in ethnic grocery stores which import their products. Many Mexican food and beverage producers, for example, still use pure cane sugar in their products.