Spatial Variation of In Vitro Starch and Protein Digestibility in White Wheat Bread

The digestibility of bread components is an important issue for the design of healthy food products. The in vitro starch and protein digestibility, and the associated morphology, moisture content, thermal (differential scanning calorimetry), and structural (Fourier transform infrared spectroscopy) changes are determined on samples obtained from different radial locations of white wheat bread slices immediately after baking. Experimental results indicated that starch in the crumb region was more digestible (approximate to 86% RDS), while the crust region contained higher amount of slowly digestible starch (approximate to 22%). On the other hand, the crust region had lower protein content than the crumb region, but the latter showed higher digestibility (approximate to 96%). The results shows that digestibility of starch and proteins in wheat bread is not uniform, but exhibits important variations from crumb to crust likely induced by spatial moisture and temperature profiles during baking.