Heat and Mass Transfer Modeling of Apple Slices Under Simultaneous Infrared Dry Blanching and Dehydration Process

摘要

To develop a new simultaneous infrared dry blanching and dehydration process for producing high-quality blanched and partially dehydrated products, apple slices with three different thicknesses, 5, 9, and 13 mm, were heated using infrared for up to 10 min at 4000 W/m~2 IR intensity. The surface and center temperatures, moisture change, and enzymatic activities of polyphenol oxidase (PPO) and peroxidase (POD) of apple slices were determined. The models of heat and mass transfer and enzyme inactivation were developed for predicting the blanching and dehydration performance. In the model development, the apple slices were assumed as one dimensional with heat and mass transfer only occurring in one direction. The enzyme inactivation followed first-order kinetics. The models were solved using a finite element method. The predicted temperature and moisture profiles and inactivation rate of enzymes were found to be in good agreement with the experimental data. This indicated that the process of simultaneous dry blanching and dehydration of apple slices under IR heating can be predicted with the developed models.