Enzymatic Pretreatment Effects on the Drying Process in Terms of Kinetics, Physical and Structural Aspects of the Vegetable Carrot <em>Daucus carota</em>

Abstract

This study is part of a large comparative study of various pre-treatments used to improve the technological abilities of plants. This study is specifically designed to systematically analyze the intensification of vacuum drying of carrots using cellulase, pectinase and macerozyme as a way to change both structure and functional behavior. These enzymatic pretreatments resulted in major changes in porosity, drying time, capacity and rehydration kinetics and water activity. However, their effects were fundamentally different from physical pretreatments generally used to increase technological capability of drying carrots, such as Freezing/Thawing (FT) instantaneous controlled pressure drop (DIC), or Simple Steaming (SS). Thus, in enzymatic pretreatments no correlation was observed in terms of structure and functional characteristics. This completely contrasts with FT, DIC and SS as thermal/texturing pretreatments, where we found that functional properties strictly depend on structural modifications. Thus thermal/texturing pretreatment operations involve systematically a high correlation between porosity and the ability to dehydration and rehydration. The changes induced by the enzyme pretreatments were closely linked to irreversible microscopic changes of the polymer chains.