Using confocal laser scanning microscopy to examine the breakdown of fat layers in laminated dough

- Small void spaces were of the typical size of starch granules.
- Larger void spaces were filled with dough; their length did not exceed a few centimeters.
- The size of small void spaces was independent on the sheeting step.
- The number of large void spaces was dependent on the number of sheeting steps.
- The greater the number of fat layers, the greater the number of void spaces.

The mechanism commonly assumed to explain the exceptional lift of laminated doughs is that fat layers act as a barrier to steam produced during baking. Successive folding and sheeting steps increase the number of fat layers and the lift, up to a point (48 fat layers in our study) where fat layers would suddenly rupture. Void spaces in the fat layers were characterized on confocal laser scanning microscopy images of Danish pastry from 8 to 64 fat layers: the greater the number of fat layers, the greater the average number of void spaces, following a power law from 16 layers. At 64 fat layers, Danish pastry appeared to be over-laminated. The size of small void spaces (2-50 μm) was shown to be independent of the number of fat layers. The number of large void spaces was linearly dependent on the number of fat layers. These results failed to show any transition at 48 fat layers.