Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences (CAAS)/Key Laboratory of Agro-Products Processing, Ministry of Agriculture and Rural Affairs, Beijing 100193, China.
Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences (CAAS)/Key Laboratory of Agro-Products Processing, Ministry of Agriculture and Rural Affairs, Beijing 100193, China.
Food Chem. 2022 Jul 30;383:132360. doi: 10.1016/j.foodchem.2022.132360. Epub 2022 Feb 6.
Shiitake mushrooms are unique in their porous structure, which could be affected by various chemical/physical changes during freeze-drying process. In this work, rehydration characteristics of freeze-dried products which were pre-frozen at -20 ℃, -40 ℃, -80 ℃, and -196 ℃ (by liquid nitrogen) were explored from aspects of pores and cell wall fibrous material. Although the appearance and rehydration rate of freeze-dried samples was better than hot-air dried samples with drying temperature ranging from 30 ℃ to 90 ℃, the final rehydration ratio was still less than hot-air dried samples dried at low temperature (30 ℃ and 40 ℃) due to the more serious structural damage by freeze-drying. Hydration capacity of the cell wall fiber was increased by freeze-drying, which might be ascribed to the loosen structure of cell wall instead of composition changes. Thus, hot-air drying at low temperature is still recommend and freeze-drying should be further optimized.
香菇具有独特的多孔结构，在冷冻干燥过程中会受到各种化学/物理变化的影响。在这项工作中，从孔和细胞壁纤维材料的角度探讨了在-20℃、-40℃、-80℃和-196℃（液氮）下预冷冻的冷冻干燥产品的复水特性。尽管冷冻干燥样品的外观和复水率优于在 30℃至 90℃范围内干燥的热风干燥样品，但由于冷冻干燥造成的结构损伤更严重，最终的复水率仍低于低温（30℃和 40℃）热风干燥的样品。冷冻干燥会增加细胞壁纤维的水合能力，这可能归因于细胞壁的疏松结构，而不是组成的变化。因此，仍然建议低温热风干燥，并且应进一步优化冷冻干燥。
