Quantification in starch microstructure as a function of baking time

The purpose of this study was the characterization of micro structural and thermal aspects of starch gelatinization in wheat dough/crumb during bread baking. The microstructure of starch granules was examined by confocal-laserscanning-microscopy (CLSM) and evaluated by an image analyzing tool. Supporting crystallinity changes in wheat dough/crumb were analyzed by differential-scanning-calorimetry (DSC) and calculated by the content of terminal extent of starch gelatinization (TEG). The micrograph of processed CLSM data showed starch structure changes during baking time. After gelatinization the starch fraction itself was inhomogeneous and consisted of swollen and interconnected starch granules. Image processing analyses showed an increment of mean granule area and perimeter of the starch granules. The results of DSC were examined to present an equation which provides a mean of predicting TEG values as a function of baking time. CLSM and DSC measurements present high significant linear correlation between mean starch granule area and TEG (r = 0.85). The possibility to combine CLSM with thermal physical analytical techniques like DSC in the same experiments is useful to obtain detailed structural information of complex food systems like wheat bread. Finally, it offers the option to enlarge the knowledge of microstructural starch changes during baking in combination with physicochemical transformation of starch components.