Abstract

In order to protect the quality of peanuts after harvest and increase the efficiency of hot-air drying, a dryer based on superposition and variable temperature control technology was built. Samples layered with a thickness of 60 mm were dried with hot air temperatures of 70 °C, 90 °C, and 110 °C. Variable temperature drying was performed in three stages, including 110 °C hot air with a sample layer thickness of 30 mm, 90 °C hot air with a sample layer thickness of 60 mm, and 70 °C hot air with a sample layer thickness of 120 mm. The change in the temperature, moisture ratio, and state were monitored during the drying process. It was found that the temperature distribution for peanuts was uneven at the beginning stage of hot-air drying, but gradually became uniform as the drying proceeded. Low-field nuclear magnetic resonance and magnetic resonance imaging (LF-NMR/MRI) analysis showed that the water in fresh peanuts was mainly distributed inside the cotyledons. The amount of free water, immobilized water, and bound water varied during the drying process, when the signal amplitudes of the free water and total water were significantly reduced, and the moisture state moved in the direction closely associated with the organic components. The results of infrared thermography and MRI showed that there was satisfactory moisture and heat diffusion uniformity for peanuts during the process. This study will provide a reference for improving the hot-air drying technology of agricultural products.

摘要

为保护花生收获后的品质，提高热风干燥效率，研制了一种基于叠加变温控制技术的干燥机。用 70 °C、90 °C 和 110 °C 的热空气温度干燥厚度为 60 mm 的样品。变温干燥分三个阶段进行，包括样品层厚度为30 mm的110°C热风、样品层厚度为60 mm的90°C热风和样品层厚度为70°C的热风120 毫米。在干燥过程中监测温度、水分比和状态的变化。研究发现，花生在热风干燥初期温度分布不均匀，但随着干燥的进行逐渐趋于均匀。低场核磁共振和磁共振成像（LF-NMR/MRI）分析表明，新鲜花生中的水分主要分布在子叶内部。干燥过程中游离水、固定化水和结合水的含量发生变化，此时游离水和总水的信号幅度显着降低，水分状态向与有机组分密切相关的方向移动。红外热成像和核磁共振成像结果表明，花生在加工过程中具有良好的水分和热扩散均匀性。本研究将为改进农产品热风干燥技术提供参考。固定水和结合水在干燥过程中发生变化，此时游离水和总水的信号幅度显着降低，水分状态向与有机组分密切相关的方向移动。红外热成像和核磁共振成像结果表明，花生在加工过程中具有良好的水分和热扩散均匀性。本研究将为改进农产品热风干燥技术提供参考。固定水和结合水在干燥过程中发生变化，此时游离水和总水的信号幅度显着降低，水分状态向与有机组分密切相关的方向移动。红外热成像和核磁共振成像结果表明，花生在加工过程中具有良好的水分和热扩散均匀性。本研究将为改进农产品热风干燥技术提供参考。红外热成像和核磁共振成像结果表明，花生在加工过程中具有良好的水分和热扩散均匀性。本研究将为改进农产品热风干燥技术提供参考。红外热成像和核磁共振成像结果表明，花生在加工过程中具有良好的水分和热扩散均匀性。本研究将为改进农产品热风干燥技术提供参考。