Science Fair Project Encyclopedia
Corn syrup is a syrup made from maize, composed mainly of glucose. It is used to sweeten soft drinks, juices, ice cream, and many other mass-produced foods. Its liquid form keeps foods moist and prevents them from quickly spoiling. In many areas it is less expensive than table sugar due to agricultural policy, e.g. the United States subsidizes its production while taxing sugar imports.
High fructose corn syrup
A variety of corn syrup called high fructose corn syrup (or HFCS) is often used to cheaply improve the flavor of food. A portion of the glucose in ordinary corn syrup is converted to fructose through the incubation with the enzyme glucose isomerase. This process, invented by Japanese researchers in the 1970s, increases the fructose content of corn syrup to 42%. Because fructose is a much sweeter monosaccharide than glucose, the sweetness of the syrup increases relative to corn syrup. Fructose is also more desirable than glucose as it increases in solubility at low temperatures (so more can be concentrated per unit weight). Through further processing, the fructose content can be increased to 55% (yielding a product that has the same sweetness as sucrose) or any desired higher amount. Common commercial grades of high fructose corn syrup include grades having 42%, 55%, or 90% fructose.
Comparison to other sugars
Sucrose (table sugar) is a disaccharide composed of one unit each of fructose and glucose linked together. Sucrose is broken down into fructose and glucose during digestion via hydrolysis. Since sucrose is 50% fructose, HFCS may have a higher or lower fructose content than sucrose.
Honey is another product that is a mixture of different types of sugars, water, and small amounts of other compounds. Honey typically has a fructose/glucose ratio similar to HFCS, as well as containing some sucrose and other sugars.
Link to obesity
High fructose corn syrup is often cited by some nutritionists as one of the leading causes of obesity. The average American consumed 62.6 pounds of high fructose corn syrup in 2001, most of which from soft drinks. Since HFCS is used as a substitute for other sugars, particularly sucrose, in processed foods, it is not clear whether it is the chemical differences between sugars or a general increase in consumption of sugars of all types that might be linked with obesity.
Some nutritionists and natural food advocates believe that consumption of high fructose corn syrup should be avoided due to its possible links with obesity. Also cited as reasons to avoid HFCS are that it is highly refined, that it might be produced from genetically modified corn, that various molds found on corn might leave harmful byproducts in the final product, or that corn (maize) products in general should be avoided. ,  Other nutritionists say that HFCS is no more or less harmful than other forms of sugar and that all sugars should be consumed sparingly. It may be the case that confusion has arisen between the effects of consuming pure fructose as compared to pure glucose, versus the effects of consuming mixtures of the two sugars from different sources.
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details