This invention is related to food processing and preservation in general, and in particular, dehydration of mushroom using microwave (MW) enhanced hot air heating and drying system. The steps in processing of mushroom are washing, sorting, slicing, blanching and drying operation. This invention works by applying microwave energy to heat up the food product for simultaneous blanching and partial dehydration and then followed by hot air drying to accelerate the dehydriition process. This technology does not involve the addition of steam or water for the blanching process so it has been named "dry blanching" technology. Conventional blanching requires use of steam or water. The microwave dry blanching technology is intended to be a replacement of steamiwater blanching technique. The partial removal of the moisture during blanching makes the whole drying process more energy efficient than conventional method. In general, the advantages of microwave dry blanching are 1) Elimination of need of water or steam for blanching 2) Achieving blanching and partial dehydration in single step 3) Reduce the processing time significantly making it more energy efficient process.