Effect of water content and molecular weight on the moisture isotherms and glass transition properties of inulin

Inulin is being used more and more in foods due to its ability to add functionality either as a sweetener or fat replacer and also for its nutritional benefits. In this research, moisture sorption isotherms and glass transition temperature (T_g) as a function of moisture content and molecular weight for four inulins were determined. The T_g of the inulins was related to moisture content and also molecular weight. As with maltodextrins, the extent of lowering T_g was directly related to the average chain length (lower T_g with lower chain length). The sorption properties are also similar to maltodextrins, thus inulin may be useful in providing similar functionality as maltodextrins with almost no calories (1.5 kcal/g).