What is the difference between high fructose corn syrup and refined sugar, chemically speaking?
Well aside from the water in the syrup, one’s fructose and the other is sucrose. Fructose is a monosaccharide (single sugar molecule) present in fruits and some vegetables. Sucrose is a disaccharide (two sugar molecules) composed of a glucose molecule and a fructose molecule. Sugar molecules, for the most part, have the same chemical formulae and very similar structures, but differ in the relative positions of certain key components (if you know any chemistry, there are several hydroxyl groups in a sugar molecule, and the different sugars have those groups in different chiral arrangements).
It is my understanding that even “high fructose” corn syrup contains roughly equal quantities of fructose and glucose.