Determination of deformation of a food product undergoing different drying methods and conditions via evolution of a shape factor

Abstract

Shrinkage is a phenomenon that is common during drying of foods and other bio-products. Attempts have been made to describe shrinkage of different products undergoing different drying processes and conditions. However, most works describe shrinkage only in terms of its magnitude but fail to describe it in terms of pattern or, in other words, of how the drying material deforms during drying. Although the degree of shrinkage of a product undergoing different drying processes and conditions may not be significantly different, the shrinkage pattern may not be the same. Using only the degree of shrinkage to describe shrinkage (and deformation) is therefore not adequate. The present study proposed and investigated the use of a shape factor viz. Heywood shape factor to describe the deformation of a food product (carrot cube) undergoing different drying techniques viz. low-pressure superheated steam drying and vacuum drying at different conditions. It was found that the evolution of Heywood shape factor agreed reasonably well with the deformation kinetics of carrot cube as observed visually. It was possible, to some extent, to use this shape factor to describe the effects of drying methods and conditions on the deformation of carrot cube.