猴頭菇是亞洲重要的食藥兩用菌之一，具有降血糖、降血脂、抗潰瘍、抗腫瘤及改善神經衰弱等生理功 能，然而在乾燥過程中，猴頭菇會因內含多酚氧化酶（PPO)的作用導致褐變及品質下降。本研究之目的在探 討不同殺菁前處理（沸水、蒸汽、微波和浸漬亞硫酸氫鈉）對猴頭菇PPO活性的影響，及不同的乾燥方法（微波 真空乾燥、微波冷凍乾燥和傳統冷凍乾燥）對乾燥猴頭菇品質之影響。新鮮猴頭菇的PPO活性為128.33 units/ g，其PPO活性經沸水殺菁2 min、蒸氣殺菁2 min、微波處理2 min、浸漬於1 %亞硫酸氫鈉1 ^後，分別降為9.6、 5.5、9.4和13.8%。褐變指數在新鮮猴頭菇及經沸水殺菁2 min、蒸氣殺菁2 min、微波處理2 min、浸漬於1 %亞 硫酸氫鈉1力後，分別為8.0、6.3、6.7、6.8和4.6。將50 g猴頭菇經微波真空乾燥、微波冷凍乾燥和傳統冷凍乾 燥，其乾燥時間依序為2、3和22 h，且乾燥後之L*值最高為傳統冷凍乾燥，其次為微波冷凍乾燥和微波真空 乾燥。乾燥後之猴頭菇復水率最高為傳統冷凍乾燥，其次為微波冷凍乾燥和微波真空乾燥。故建議先以蒸氣 殺菁2 min降低猴頭菇PPO活性後，再利用微波冷凍乾燥或微波真空乾燥可以顯著減少乾燥時間和節省乾燥能 源。

Department of Food Science, National Han University, Han, Taiwan (Accepted for publication: July 25, 2013) Hericium erinaceum is one of the most important edible and medicinal mushrooms in Asia. H. erinaceum consists of several pharmacological functions, including hypoglycemic, hypolipidemic, antiulcer, antioxidant and antitumor activities, and improving neurasthenia. However, enzymatic browning reactions by polyphenoloxidase (PPO) occurs during the dehydration process, which could reduce the quality of dried H. erinaceum. Therefore, the objectives of this study were to determine the influence of different blanching pretreatments (boiling water, steam, microwave and soaking in sodium bisulfite) on PPO activity, and the qualities of dried H. erinaceum obtained by different drying methods (hot air drying, microwave vacuum drying, microwave freeze-drying and freeze-drying). The PPO activity of fresh H. erinaceum was 128.33 units/g. The PPO retention rate of H. erinaceum blanched by boiling water for 2 min, steaming for 2 min, microwave for 2 min and soaking in 1% sodium bisulfite for 1 h were 9.6, 5.5, 9.4 and 13.8%, respectively. The browning index of fresh H. erinaceum and those pre-treated with boiling water for 2 min, steam for 2 min, microwave for 2 min and soaking in 1% sodium bisulfite for 1 h were 8.0, 6.3, 6.7, 6.8 and 4.6, respectively. Therefore, steam blanching of H. erinaceum was chosen for the following drying studies. The drying time of 50 g H. erinaceum by microwave vacuum drying, microwave freeze-drying and freeze-drying were 2, 3 and 22 h, respectively. The rehydration ratios of dried H. erinaceum were ranked in a descending order as freeze-drying, microwave freeze-drying and microwave vacuum drying, respectively. The L*-values and rehydration ratio of dried H. erinaceum were ranked in a descending order as freeze-drying, microwave freeze-drying and microwave drying, respectively. Therefore, H. erinaceum was steam blanched for 2 min to effectively reduce PPO activity. Then microwave vacuum drying and microwave freeze-drying of H. erinaceum significantly reduced drying time and saved energy.