Investigation on enthalpy changes in Iranian flat breads and Baguette during storage

The aim of this research was to investigate the enthalpy variations of Iranian flat breads during storage in room temperature and determining relationship between enthalpy and amount of staling development. For this purpose, the major Iranian Breads including Barbari, Taftoon, Lavash and Sangak beside Baguette, were prepared using standard ingredients, specific recipe, and under controlled conditions. After baking and cooling, breads were packed in bi layer PE, in order to minimize the interchanges of moisture and air of products with atmosphere. Each bread was then taken out from the package at different time intervals and 20 mg sample from its crumb was weighted. In next step, thermal properties such as: enthalpy, maximum and final temperature of reactions were determined by Simultaneous Thermal Analysis (STA) method. This evaluation was performed in triplicate during 4 days storage. A factorial experiment in completely randomized design was used for statistical analysis. The results shown that the fresh breads have exothermic curves. However with increasing the storage time, curve becomes more endothermic, and these changes was not similar in all breads. Generally, according to the statistical analysis, it was found that enthalpy is not suitable for evaluation of extent of staling and shelf life in Taftoon, Lavash and Sangak. However, these changes of enthalpy had a regular and documentary trend in Barbari during first three days, althoush, using the enthalpy as parameter for predicting the extent of staling in Barbari still requires more investigation.