Glass Transition State Diagram of a Baked Cracker and Its Relationship to Gluten

The polymer science approach can be applied to the understanding of physical changes in foods such as loss of texture upon moisture gain. The glass transition temperature (T_g) of a commercial cracker was measured by Dynamic Mechanical Thermal Analysis (DMTA) as a function of water content. The final state diagram showed that the cracker was plasticized by water with a glass transition temperature that decreased as water content increased. When compared with published glass transition data on cereal ingredients, gluten may be the main component responsible for the mechanical changes and loss of crispness of such products when moisture content is increased.