Fructose, commonly called fruit sugar, is a simple sugar found in honey, tree fruits, berries, and melons. But don’t be fooled into thinking fructose on a label means you are eating fruit sugar. Pure crystalline fructose comes from two sources: corn or sucrose (table sugar). Corn starch is processed to release fructose. Sucrose (table sugar) is enzymatically hydrolyzed to separate into glucose and fructose. Crystalline fructose is pure fructose from one of these two sources.