Using an invert sugar allows you to use half the amount of regular sugar called for in a recipe. Examples of invert sugars are honey, glucose, corn syrup, and trimoline.
Definition: Invert sugar is created by combining a sugar syrup with a small amount of acid (such as cream of tartar or lemon juice) and heating. This inverts, or breaks down, the sucrose into its two components, glucose and fructose, thereby reducing the size of the sugar crystals. Because of its fine crystal structure, invert sugar produces a smoother product and is used in making candies such as fondant, and some syrups. The process of making jams and jellies automatically produces invert sugar by combining the natural acid in the fruit with granulated sugar and heating the mixture. Invert sugar can usually be found in jars in cake-decorating supply shops.
from The New Food Lover's Companion, Second Edition, by Sharon Tyler Herbst
Inversion or chemical breakdown of sucrose results in invert sugar, an equal mixture of glucose and fructose. Available commercially only in liquid form, invert sugar is sweeter than granulated sugar. One form of liquid invert was specially developed for the carbonated beverage industry and can be used only in liquid products. This liquid sugar is actually part invert sugar combined with part dissolved granulated sugar. Another type, named total invert sugar syrup, is commercially processed and is almost completely invert sugar. It is used mainly in food products to retard crystallization of sugar and retain moisture. [3,5]