Microwave Convective Drying of Plant Foods at Constant and Variable Microwave Power

Abstract

Microwave convective drying of plant foods is a promising process due to the shorter drying time and better product quality. High microwave power decreases the drying time but causes charring of the product. In this work, microwave drying under constant and variable microwave power were compared. Temperature-sensitive products, such as plant foods, are especially affected by microwave power during the final drying period. Therefore, drying at variable microwave power was found to be a more suitable drying process. Air (temperature and velocity) has an important role during microwave drying, not only as carrier of evaporated moisture but also as it contributes to a more homogeneous and faster drying.

Keywords:

• Air temperature
• Air velocity
• Charred product
• Kinetics
• Product quality

ACKNOWLEDGEMENTS

The authors gratefully acknowledge the European Commission for financial support. This work is part of the CombiDry project (ICA4-CT-2001-10034) (www.sik.se/combidry).

Notes

∗% charred pieces in 400 g dried product.