Development of Far Infrared Dryer for Siitake Mushroom

研究了香菇远红外辐射干燥机的研制。研究结果如下：1)实验制作了在波长约为2.5 ~ 25 μm波段具有典型特征的陶瓷或石英玻璃加热器内的设备。2)利用该设备对远红外辐射进行辐照，从远红外辐射加热器的表面温度、供给能力密度、加热器的辐射能量分布等光学物理性质等之间的关系，阐明了远红外辐射加热的基本加热特性，以及红外辐照特性。3)辐射能量大的加热器干燥速度最大。并证明了供给能力大的近红外辐射体的干燥速度要快于远红外辐射体的干燥速度。4)通过测量香菇表面附近的温度变化、介质的物理性质（密度、比热、导热系数），可以估算远红外辐射能量的渗透距离。长波侧的红外线能量在香菇表面被吸收，因为在超过2.5 μm的长波侧，水的吸收系数增大，而在小波长侧，则相反，吸收系数减小。结果表明，小波长侧红外线能量影响了香菇内部的温升。5)以不同干燥条件下的香菇为研究对象，考察了水分的吸水率、复水时水分的褐变、香菇游离氨基酸的变化。

This study concerns the development of the far infrared radiation drier for shiitake mushroom.Results got from this research are as follows ;1) The equipment which built in the ceramic or quartz glass heater with typical features in wavelength region of about 2.5〜25 μm was produced experimentally.2) Using this equipment, the far infrared radiation was irradiated, and from the relationship between surface temperatures, supply capability density, optical physical property such as radiation energy distribution of the heater of the far infrared radiation heater, etc., the fundamental heating characteristic of the far infrared radiation heating, and infrared irradiation characteristic was clarified.3) The drying velocity by large heater of the radiation energy was the biggest. And, it was proven that the case of the drying by the near infrared radiation radiator in which the supply capability is big was rapider than that of the drying by the far-infrared radiation body.4) By measuring the temperature change near the shiitake mushroom surface, physical properties of medium (density, specific heat, thermal conductivity), it was possible to estimate infiltration distance of the far infrared radiation energy. Infrared ray energy of the long-wavelength side is absorbed in the surface of shiitake mushroom, because in the long-wavelength side over 2.5 μm, the value of absorption coefficient of the water is increased, and because in the small wavelength side, it decreases for the contrariety. It was clarified that the small wavelength side infrared ray energy affected the temperature rise of the shiitake mushroom inside.5) On shiitake mushroom which dried under various conditions, the quality was investigated about water absorption and brown change of water at the rehydration, the change of free amino acids of shiitake mushroom.