基于低场核磁共振技术研究不同热风干燥工艺条件下香菇复水过程中的水分传递特性

摘要

以6种不同热风干燥工艺制备的干香菇为研究对象,利用低场核磁共振(low-field nuclear magnetic resonance,LF-NMR)与核磁共振成像(nuclear magnetic resonance imaging,MRI)技术研究干香菇复水过程中水分变化规律.结果表明,根据T2弛豫时间显示,伴随复水时间的延长,香菇体内水分的主要状态是不易流动水而并非自由水.非均匀间歇干燥(non-uniform intermittent drying,NUID)组水分信号明显强于其他各组,复水能力较强,均匀间歇干燥(uniform intermittent drying,UID)组复水能力相对较弱.因此,提升复水效率的关键在于保证干燥过程中香菇水分的均匀转移,以便复水时具有良好的保持不易流动水的能力.%The objective of this study was to analysis the moisture change of dried mushroom (Lentinus edodes) by six different drying methods during rehydration process.The tests were performed by low-field nuclear magnetic resonance and nuclear magnetic resonance imaging technology.The T2 relaxation test showed that with the extension of rehydration time,the main state of water in dried mushroom was immobilized water instead of free water.The water signal of non-uniform intermittent drying (NUID) group was significantly stronger than other groups,which indicated its best rehydration capacity.The Uniform intermittent drying (UID) group had the poorest rehydration capacity.The key to improve the rehydration efficiency is to ensure the uniform transfer of water in the process of drying in order to have a good ability to maintain the immobilized water during rehydration process.