A Study on Microwave Condensation Drying of Mushroom

乾燥可降低農產品含水率，抑制微生物及酵素的作用，提高食品貯藏性及增加運輸性。本研究開發微波冷凝乾燥設備並進行香菇乾燥試驗，以香菇之溼基含水率13%為目標值。若欲達到此目標含水率，則熱風乾燥溫度設定50℃時，需作用24 小時，使用電能89.8 度；加入時序控制後，四段式熱風乾燥須20 小時，消耗電能74.9 度；若在與熱風乾燥相同操作條件下配合微波技術，則只需7 小時，使用能源為28.5 度；如果同時使用微波與冷凝技術，亦只需7 小時，使用能源為78 度。依據實驗結果得知，本計畫所研發具備時序控制功能之微波冷凝乾燥設備，可根據不同乾燥階段，改變乾燥策略，有效控制乾燥品質並節省人力；而微波乾燥比熱風乾燥可節省7 成以上之乾燥時間。 The purpose of this study was to establish a sequence controlled microwave condensation drying system for mushroom drying. The utilization of hot air, microwave and/or condensation drying method in different drying period coordinated with the drying characteristics of the mushroom to insure the drying quality of the product as well as saving time and cost. The drying experiment of the microwave condensation dryer with only the hot air set at 50℃ took 24 hours to bring moisture content level down to 13% and consumed 89.8 kWh electricity. If the sequence control was implemented, the four-stage hot air drying took 20 hours to dry the mushroom to 13% moisture content and consumed 74.9 kWh electricity. If the hot air was set at 50℃with the microwave was introduced, the drying time was reduced to 7 hours and consumed 28.5 kWh electricity. If the 50℃ hot air accompanied by microwave and condensation, the drying time was 7 hours but the electric energy consumption was 74.9 kWh. The experiment showed that the sequence controlled microwave condensation dryer developed in the research could adjust mushroom drying strategy in different drying period to keep the quality of the product as well as saving the labor and drying time up to 70%