A proposed mechanism of high temperature puffing of potato. Part II. Influence of blanching and initial drying on the permeability of the partially dried layer to water vapour Original Research Article

The permeability of the surface layer, the partially dried layer (PDL), to water vapour was measured. It was found that blanching reduced the permeability of the surface layer to water vapour. This was shown to be due to gelatinisation of starch on the surface. This finding was confirmed by examining the structure of the surface layer using stereomicroscopy and variable pressure scanning electron microscopy.