Contribution of major ingredients during baking of biscuit dough systems

Nineteen dough systems were made of a combination of two to nine of the following ingredients: flour, water, fats (coconut and/or palm oils), sugars (sucrose, invert) and chemical leaveners (ammonium bicarbonate, sodium bicarbonate, citric acid and sodium acid pyrophosphate). Their thermal behaviour was studied over a large temperature scale (20 degrees C to 160 degrees C). Thermal analysis of baking by three different methods (DSC, DMTA and TGA) at the same heating rate (3 degrees C/min) provided information about phase transitions, volume and mass changes of doughs during heating. Temperature ranges over which all ingredients reacted were identified. Melting transitions of fats occurred between 10 degrees C and 50 degrees C. Sugars increase temperatures of starch transitions. Chemical leaveners decrease rise temperature, whereas fats and sugars have a delaying effect on their action. The texture of biscuits results from interactions between ingredients; complete dough cannot thus be considered as merely a simple addition of all components.