为探究二氧化碳浸渍处理对生姜真空微波干燥特性及微观结构的影响，分别选用不同浸渍温度（35、40、45 ℃）、压力（1、2、3 MPa）、时间（3、5、7 h）对生姜进行预处理，测定干燥过程中水分比、干燥速率、有效扩散系数的变化，并进行薄层干燥模型拟合。此外，对不同浸渍条件下生姜的微观结构进行研究。试验结果显示：经二氧化碳浸渍后，生姜的干燥速率显著提高，尤其在干燥后期。当浸渍条件为2 MPa、45 ℃、7 h时，样品的水分扩散最快，且干燥时间相比于直接干燥样品缩短了47%。5种薄层干燥模型中，通过比较决定系数（R2）、卡方（χ2）和均方根差（RMSE），认为Modified Page模型对生姜干燥过程中水分变化的拟合效果最好。扫描电镜结果显示，二氧化碳浸渍增大了生姜内部的细胞面积，增加孔隙率，提高物料的传质传热性能。结果表明，二氧化碳浸渍对于改善生姜内部结构、提高干燥效率具有积极的影响，为生姜干燥新技术的开发提供了理论依据。

In order to study the effects of carbon dioxide impregnation (CDI) on the microwave-vacuum drying characteristics and microstructure of ginger, different temperatures (35, 40, 45 ℃), pressures (1, 2, 3 MPa) and treatment times (3, 5, 7 h) were selected for CDI to pretreat ginger. The changes in moisture ratio, drying rate, effective diffusion coefficient of ginger during drying were measured, and the mathematical model for thin layer drying was fitted. In addition, the microstructures of ginger under different CDI conditions were also studied. The results showed that after CDI, the rate of drying ginger significantly increased, especially in the late drying stage. When the ginger was pretreated at 2 MPa and 45 ℃ for 7 h, the moisture diffusion was the fastest, and the drying time was shortened by 47% compared to that for the sample dried directly. Among the five thin layer drying models, the Modified Page model exhibited the best fit to the changes in ginger’s moisture content during drying, based on the coefficient of determination (R2), chi-square (χ2) and root mean square error (RMSE). Scanning electron microscopy revealed that CDI increased the cell area and porosity of ginger tissues, and enhanced the mass and heat transfer of the material. Therefore, CDI had a positive effect on improving the internal structure and drying efficiency of ginger. The results obtained in this study provide the theoretical basis for the development of new drying technologies for ginger.

国家重点研发计划项目（2017YFD0400900；2017YFD0400904）；国家自然科学基金项目（31501500）