SHRINKAGE IN DEHYDRATION OF ROOT VEGETABLES

Abstract

ABSTRACT The shrinkage in dehydration of root vegetables such as carrots, potatoes, sweet potatoes and radishes was investigated. The samples were dried in flowing hot air. The surface areas were measured by photographing the samples. Three drying models were postulated for the formulation of the relation between the changes of the surface area and the moisture contents. The uniform drying model, which in the case of drying is that the shrinkage in volume equals the volume of water lost by the evaporation, agreed with the measured values during the early stages of the drying. The core drying model by assuming the formation of the dried layer at outer side of material was better in agreement with the experimental results. The semicore drying model, which is the intermediate model between the uniform and the core drying model, and the empirical equations of the shrinkage were also considered.