Bread collapse. Causes of the technological defect and impact of depanning time on bread quality

•Collapse of the sides of sliced bread is a technological problem for baking industry.•Greater collapse was observed for bread kept longer in the pan before depanning.•The collapse is probably due to the cells shrinking of bread sides cells.•Water condensed on the wall of the pan forms a film at the bottom interface pan-bread.•This film explains the increased depanning force observed.

The collapse of the sides of sliced bread is a technological problem for the baking industry. This study aims to understand the possible link between bread structures, internal pressure gradient, waiting time in the pan before depanning, and side collapse. The collapse variation was measured using laser to get bread profiles, and using image analysis of bread slices. The pressure variation at the centre and at the periphery was measured, and the product structure was observed using X-ray microtomography. The collapse increases with the cooling time in pan. The pressure in the cells is always higher than pressure in ambiance and cannot explain the collapse. The bread structure measurements indicate that the collapse is probably due to the cells shrinking of bread sides cells. A complementary explanation is to be searched in the specific volume variation of the material constituting the dough and the bread during the baking and the cooling.