The commercial value of high fructose corn syrup is based on the increased sweetness of the High Fructose Corn Syrup (HFCS) compared to the starting material glucose obtained from starch. On sweetness comparison basis glucose is only about 70% as sweet as sucrose whereas fructose is sweeter compared to sucrose to the extent of 20–60% depending conditions used.
The abundant supplies of cheap corn in USA, as well as efficient processing techniques and valuable by-products such as corn oil and protein provide the basis for the low cost manufacture of HFCS. Typical syrups made from starch contain a mixture of glucose, fructose, and other saccharides. The equilibrium limitation of the enzymatic conversion of glucose to fructose, as well as sweetness and manufacturing cost restrictions, led to the development of fructose syrups containing 42% fructose on a dry basis to replace liquid sucrose in many food applications.
The first stage in HFCS production is the hydrolysis of polymer corn starch containing about 74% amylopectin and 26% amylase to monomeric glucose.
In the later stages of HFCS production, large scale chromatographic techniques are use to produce syrups with the various proportions of fructose and glucose. The degree of isomerisation (DI) is the percentage of sugars dry basis, 52% glucose and 6% higher sugars. It is common practice to incorporate the DI value in the product description.
Ultra high fructose corn syrup (UHFCS) is generally restricted to those syrups having a DI value greater than 50. Sometimes ultra high fructose glucose syrup or second generation HFCS are used instead of HFCS.
There are three main stages involving three different enzymes may be identified in the manufacturing process of HFCS. These include
Liquefaction of starch
Saccharification
Isomerisation
High Fructose Corn Syrup
