Liquid imbibition during rehydration of dry porous foods

Dry food particulates are an integrative part of many soups and ready-to-eat products. The increased consumers demand for convenience foods makes fast rehydration a significant quality consideration. Better understanding of the transport phenomena occurring in dried foods containing particulates is paramount to facilitate product reconstitution and improving consumer acceptance. This study highlights the complexity encountered in modeling of the rehydration process of freeze-dried (FD) carrots. The commonly assumed Fick's diffusion law was replaced with a physical model describing the capillary imbibition into a porous media. This approach offers to analyze the complex phenomena occurring during rehydration. Viscosity of the rehydration medium was found not to be the sole factor responsible for the decrease in the rehydration. Due to the encountered complexity in modeling, the need for further research on physical properties usually disregarded (e.g., tortuosity, roundness of pores, contact angle, swelling) is suggested. This could open new avenues for the optimization of the process. As the drying process affects significantly some of the physical properties and the rehydration of the food particulates, a system approach is recommended.