Microwave drying characteristics of button mushroom (Agaricus bisporus)

Microwave drying behaviour of button mushroom was experimentally studied in relation to pretreattnents (I) Blanching in boiling water for 3 min. and steeping in solution of 0.5% NaHSO3 + 0.25% citric acid(CA)at room temperature for 15 min., (II) Blanching in boiling water for 3 min. and steeping in solution of 1 % KMS + 0.25% CA at room temperature for 15 min., (III) Blanching in boiling water for 3 min. and steeping in solution to 0.1% KMS + 0.2% CA + 6% sugar + 3% NaCl at room temperature for 15 min., (IV) Steeping in solution of 0.5% KMS at room temperature for 15 min.; no blanching, and (V) Steeping in solution of 0.1% KMS + 0.2% CA + 6% sugar + 3% NaCl at room temperature for 15 min.; (no blanching) and microwave power levels (155, 215, 275, 340 and 400 W). The optimum conditions of drying were established on the basis of rehydration ratio and sensory evaluation, Drying with pretreatment of blanching in boiling water for 3 min. followed by steeping in solution of 0.1% KMS + 0.2% CA + 6% sugar + 3% NaCl at room temperature for 15 min. at the microwave intensity of 400 W yielded an acceptable dehydrated product in about 45 min. The drying process could be described by the Page's model. The estimated electrical energy use efficiency was found to he 75%..