目的 建立防己Stephaniae Tetrandrae Radix趁鲜切制热风干燥的干燥动力学模型，测定其干燥特性参数，研究其干燥过程中的成分变化规律，为阐明防己趁鲜切制热风干燥机制及干燥工艺提供参考依据。方法 在60、70、80 ℃条件下建立防己趁鲜切制干燥过程中的干燥动力学模型，基于低场核磁共振技术研究防己干燥过程中的水分相态，根据Fick扩散定律和Arrhenius方程计算出有效扩散系数（effective diffusion coefficient，D_eff）和活化能（activation energy，E_a），采用HPLC法对防己干燥过程中指标成分粉防己碱和防己诺林碱的质量分数进行动态监测。结果 Page模型（MR＝e^−ktn，MR为水分比，k，n为模型参数）可以准确地描述防己干燥过程中水分含量的变化，温度越高，水分散失越快，模型中的参数k随着温度的升高而增大，参数n随着温度的升高而减小；60、70、80℃热风干燥条件下的D_eff分别为8.13×10⁻⁷、9.97×10⁻⁷、1.04×10⁻⁶ m²/s，D_eff随着温度的升高而增大；防己趁鲜切制热风干燥的E_a为12.51 kJ/mol。横向弛豫时间（T₂）图谱显示，4 h之前水分相态发生显著变化，自由水比例大幅下降，水的自由度逐渐降低；4 h之后水分含量和相态无明显变化。防己在趁鲜切制干燥过程中，粉防己碱和防己诺林碱总含量无明显波动。结论 采用干燥动力学模型和低场核磁共振技术可以直观地描述防己趁鲜切制干燥过程中的水分变化规律；为阐明防己趁鲜切制干燥机制和干燥工艺提供参考。

Objective To establish the drying kinetic model of Fangji (Stephaniae Tetrandrae Radix, STR) fresh-cut hot air drying, determine its drying characteristic parameters, and study the variation of its components during the drying process, so as to provide a reference for elucidating the drying mechanism of STR fresh-cut and optimizing the drying process. Methods The drying kinetics model of STR during fresh-cut drying was established at 60, 70, 80 ℃. The water phase in the drying process of STR was studied based on low-field nuclear magnetic resonance technology. The effective diffusion coefficient (D_eff) and activation energy (E_a) were calculated according to Fick’s diffusion law and Arrhenius equation. The mass fraction of tetrandrine and fangchinoline in the drying process of STR was investigated by HPLC for dynamic monitoring. Results The Page model (MR = e^−ktn, MR is water ratio, k, n are model parameters) could accurately describe the change of moisture content in the drying process of STR. The higher the temperature, the faster the moisture loss. The k in the model increased with the increase of temperature, and the n decreased with the increase of temperature. D_eff were 8.13×10⁻⁷, 9.97×10⁻⁷, 1.04×10⁻⁶ m²/s at 60, 70, 80 ℃, and the effective diffusion coefficient increases with the increase of temperature. The E_a value was 12.51 kJ/mol. The T₂ spectrum showed that the water phase changed significantly before 4 h, the proportion of free water decreased significantly, and the degree of freedom of water decreased gradually. There was no significant change in water content and phase state after 4 h. In the process of fresh-cut drying, the total content of tetrandrine and fangchinoline had no obvious fluctuation. Conclusion The drying kinetics model and low field nuclear magnetic resonance technology can intuitively describe the moisture change law of STR during fresh-cut drying process. It provides a reference for elucidating the drying mechanism and drying process optimization of STR fresh-cut.

R283.6

国家自然科学基金项目（82060724）;国家自然科学基金项目（82460772）;省重点研发计划项目（20243BBI91015）;江西省中医药标准化项目（2023A19）;江西省高水平本科教学团队（2252201013）;校级虚拟教研室（2252300109）