Development of Far Infrared Dryer for Siitake Mushroom

本研究是关于香菇远红外辐射干燥机的研制，主要研究结果如下：1）实验制作了在2.5 ~ 25 μm波长范围内具有典型特征的陶瓷或石英玻璃加热器的装置。2）利用该装置进行远红外辐射照射，从表面温度的关系，供应能力密度、远红外辐射加热器的加热器的辐射能量分布等光学物理性质，阐明了远红外辐射加热的基本加热特性和红外辐射特性; 3）辐射能量大的加热器干燥速度最大。证明了供给能力大的近红外辐射体的干燥速度比远红外辐射体的干燥速度快。4）通过测定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。长波长一侧的红外线能量被香菇表面吸收，在2.5 μm以上的长波长一侧，水分的吸收系数值增大，而在短波长一侧，水分的吸收系数值减小。5）以不同干燥条件下的香菇为研究对象，研究了不同干燥条件下香菇复水时的吸水率、水分褐变、游离氨基酸含量的变化。

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.