Effect of blanching on structural quality of dried potato slices

Mechanical properties of potato slices were monitored during blanching, as indicators of structural changes. As expected, blanching resulted in weakening of potato structure. Gelatinization, which occurred during the first 2 min, did not promote an immediate weakening of the potato tissue. More than 80% of the changes in mechanical properties occurred during the first 30 min of blanching. Potato slices blanched for 2 and 30 min as well as unblanched ones were dried in a convective air drier at 48 degrees C. Bulk and true density, porosity, and shrinkage were monitored with time. Blanched potatoes resulted in a significantly more compact, less porous product with lower effective water diffusivity than unblanched potatoes. The results indicated that changes that occurred during the first 2 min of blanching had a much greater influence on structural quality of dried potatoes than changes that occurred from 2 to 30 min of blanching.