That is why you add vinegar to some recipes. A number of familiar products use inverted sugars. Fondant centers, fudge, butter confectioners, chewing gum, jellies, caramels and toffees, hard creams, high boiled sweets, butterscotch, marshmallow and soft creams all are results of this inversion process being careful controlled. High levels of inverted sugar, particular fructose, pick up moisture from the air and the water is deposited on the surface of the candy. The third chemical process taking place when you make candies is called the Maillard Reaction.
Proteins react with the inverted sugars, adding flavor, texture, and color.
Milk is usually the protein used and it is an essential part of making caramels, toffees, and fudge. The main effect during the production of sugar confections is the change from ingredients to a highly saturated syrup. This syrup determines the crystalline form the final product will take. How hot you cook the syrup and how you stir and agitate it will make huge differences in the final results. So will the amounts of ingredients and the way you cool this hot sugar syrup.