该研究采用低场核磁共振技术（LF-NMR）结合干燥曲线，探讨了热泵干燥和变温压差膨化干燥对蚕蛹水分迁移变化规律的影响，揭示两种不同干燥过程中蚕蛹内部的水分状态、分布、含量的情况。结果表明，变温压差膨化干燥（EPD）在干燥过程中水分下降较快，其干燥速率也快于热泵干燥（HPD）。新鲜蚕蛹水分可分为结合水T21（0~2 ms）、不易流动水T22（2~100 ms）和自由水T23（100~1000 ms）三部分，对应3个峰的峰面积分别为：49.531、661.651、1730.075，峰面积占比分别为2.03%、27.10%、70.87%。蚕蛹随着干燥时间的延长，EPD和HPD 2种干燥方式下T2弛豫时间均呈现出相同的变化趋势，一方面是峰位置向左迁移，另一方面是总峰面积A总不断减小，水分的主要状态逐步变成不易流动水和结合水。EPD和HPD 2种干燥方式下干基含水量x和总峰面积A总之间的关系方程分别为A总=702.01x+173.92（R2=0.9997）及A总=695.94x+229.24（R2=0.9968），两者均呈显著的线性关系（p<0.05），其中EPD拟合度更好，但HPD过程的氢质子密度分布相对均匀。综合考虑EPD能更好描述蚕蛹干燥过程中水分迁移规律。

In this study, low-field nuclear magnetic resonance (LF-NMR) technique combined with drying curve was used to investigate the influence of heat pump drying and variable temperature differential pressure puffing drying (EPD) on the moisture migration of silkworm pupa, to reveal the state, distribution, and content of moisture inside silkworm pupa during two different drying processes. The results showed that EPD led to a more rapid moisture decrease during the drying process, and its drying rate was also higher than that of the heat pump drying (HPD). The moisture of fresh silkworm pupa could be divided into three parts: bound water T21 (0~2 ms), non-flowing water T22 (2~100 ms) and free water T23 (100~1000 ms), with their corresponding peak areas of the three peaks as 49.531, 661.651, and 1730.075, respectively, and peak area percentages as 2.03%, 27.10%, and 70.87%, respectively. With the extension of the drying time for the silkworm pupa, the T2 relaxation time of the EPD and HPD showed the same changing trend. On one hand, the peak position shifted to the left, and on the other hand, the total peak area A kept decreasing. The main state of moisture gradually became non-flowing water and bound water. The relationship equations between the moisture content on dry basis (x) and the total peak area A under the two drying methods, EPD and HPD, were A=702.01x+173.92 (R2=0.9997) and A=695.94x+229.24 (R2=0.9968), respectively. Both showed a significant linear relationship (p<0.05), with EPD showing a better fit, but HPD having a relatively uniform distribution of hydrogen proton density. Comprehensive evaluation revealed that EPD can describe better the water migration law during the drying process of silkworm pupa.

广西壮族自治区科技厅现代食品加工新技术研究岗位创新人才培养示范基地建设项目（桂科AD17195088）