Influence of osmotic dehydration on microwave-convective drying of frozen strawberries

In this work, drying of frozen strawberries in temperature of 55 degreesC using microwave-assisted convective or only convective method was analysed. Strawberries not osmo-dehydrated were dried at seven levels of microwaves doses, and osmo-dehydrated ones-at four levels (from 0 to 1.7 W/g). Increase of microwave doses in microwave/air drying influenced on shortening of process time both for osmotically dehydrated strawberries, as well for raw not dehydrated material. For processes carried out without microwave aid use of osmotic dehydration caused decreasing of final drying time, while implementation of osmotic dehydration before microwave/air process did not have an influence on final drying time. The introduction of osmotic dehydration when the same microwave doses were applied allowed decreasing drying time only for processes aimed to obtain 50% of water content. (C) 2004 Elsevier Ltd. All rights reserved.