Characterisation of structural patterns in bread as evaluated by X-ray computer tomography

•A stitching strategy was used to combine X-ray computer tomography images of bread slices.•Spatial parameter maps across a whole slice of bread were generated.•Addition of wheat bran resulted in significant changes in morphological parameters.•Microstructural heterogeneity varied significantly between all samples.•Cross sections along the three axes of pan baked bread showed effects of molding actions.

X-ray micro-tomography and a volume stitching strategy were combined to create a high resolution 3D image of entire cross sections (slices) of bread. Morphological analysis of whole slices revealed structural properties on a product scale. The addition of wheat bran yielded a lower loaf volume, higher structure thickness and a higher number of closed pores, while maintaining a similar porosity to its no-bran counterpart. Freestanding bread loaves had a higher loaf volume, a lower structure thickness and a higher porosity than pan baked bread. Remarkably, variations between batches of each type of bread were found to be rather small when judging them by these parameters. In addition, localized morphological analysis was applied to generate spatial maps of the porosity, the structure thickness and the number of closed pores on the cross sections of bread. This provided insight into the heterogeneity of bread, revealing localized microstructural features/defects, molding lines, crust artifacts and effects of baking kinetics. Analysis of porosity distributions revealed very significant differences between all samples and the standard deviation of these distributions proved to be a good measure for the heterogeneity across a slice of bread.