Institute of Food Science and Technology, Chinese Academy of Agricultural Science (CAAS)/Key Laboratory of Agro-Products Processing, Ministry of Agriculture and Rural Affairs, Beijing, China.
Institute of Food Bioresources Technology, Dedan Kimathi University of Technology, Nyeri, Kenya.
J Sci Food Agric. 2019 Apr;99(6):2826-2834. doi: 10.1002/jsfa.9494. Epub 2018 Dec 30.
An abundance of shiitake mushrooms is consumed in dried form around the world. In the present study, changes in water state, water distribution and microstructure of shiitake mushrooms during hot-air drying (HAD) and far-infrared radiation drying (FIRD) processes were investigated using low-field nuclear magnetic resonance and scanning electron microscopy. Quality attributes of the dried products were compared in terms of drying property, appearance, rehydration behavior, texture and storage stability.
Compared with HAD, the rate of water diffusion and evaporation of the shiitake mushrooms dried by FIRD was higher, thus resulting in a shorter drying time (630 min), a lower water content (0.07 g g wet basis) and a higher glass transition temperature (7.88 °C) for dried products. Moreover, a homogenous and porous microstructure with less shrinkage and case hardening was demonstrated by the FIRD samples, indicating a superior texture, including a larger pileus diameter (3.4 cm), a higher rehydration ratio (7.31), a lower hardness (37.93 N) and a higher crispness (1.41 mm) for FIRD shiitake mushrooms.
High-quality shiitake mushrooms with a desirable texture could be produced by FIRD by enhancing the diffusion of internal water and alleviating the case hardening during a relatively short drying process. © 2018 Society of Chemical Industry.
全世界都以干燥形式大量食用香菇。在本研究中，使用低场核磁共振和扫描电子显微镜研究了香菇在热风干燥（HAD）和远红外辐射干燥（FIRD）过程中水分状态、水分分布和微观结构的变化。从干燥特性、外观、复水性能、质地和储存稳定性等方面比较了干燥产品的质量特性。
与 HAD 相比，FIRD 干燥的香菇的水扩散和蒸发速率更高，因此干燥时间更短（630 分钟），水分含量更低（0.07 gg 湿基），玻璃化转变温度更高（7.88°C）。此外，FIRD 样品表现出均匀多孔的微观结构，收缩和硬化程度较小，表明质地较好，包括菌盖直径较大（3.4 cm）、复水率较高（7.31）、硬度较低（37.93 N）和脆性较高（1.41 mm）。
通过增强内部水分的扩散并在相对较短的干燥过程中减轻硬化，可以通过 FIRD 生产出具有理想质地的高质量香菇。 © 2018 英国化学学会。
