Fructose is a simple sugar that had a fruity taste. The name is an amalgamation of the words "fruit" and "sucrose".
In 2367, Guinan prepared a drink concoction consisting mostly Saurian brandy along with Targ milk and Denevian mead, after hearing about it on Prakal II. Lieutenant Commander Data observed that the drink contained a high concentration of fructose and monosaccharides, which Guinan interpreted as it being too sweet. (TNG: "In Theory")