Abstract: In order to compare the drying characteristics and quality of Dahongpao Zanthoxylum bungeanum Maxim (ZBM) under hot air drying, hot airinfrared drying and hot airmicrowave drying methods, and reveal the thin layer drying process of convectionradiation combined drying to guide the production practice, the effects of hot air drying, hot airinfrared drying and hot airmicrowave drying under the condition of different hot air temperatures (50 ℃, 60 ℃, 70 ℃) and different air relative humidity(10%, 30%, 50%) were analyzed by contrast with drying curve and effective moisture diffusivity. The drying kinetics was analyzed by combining the scale parameter (α), shape parameters (β) of Weibull function and the calculated moisture diffusion coefficient, the oil bud structure and volatile oil components of dried ZBM were analyzed by scanning electron microscope (SEM) and gas chromatography mass spectrometry (GCMS) respectively. The results show that the drying time of hot air drying was longest. Increasing the temperature or decreasing the humidity was helpful to improve the drying rate and shorten the drying time, but it had little effect on hot airinfrared and hot airmicrowave drying. Weibull function could well simulate the drying curves of three drying methods. The scale parameter (α) was related to the drying time and changed obviously with drying conditions. The shape parameter β>1, it showed that water migration was jointly controlled by the surface and interior of the material. The calculated moisture diffusion coefficient variation ranges of the three drying methods were 1.303×10-7-2.815×10-7 m2/min、7.646×10-7-9.628×10-7 m2/min、2.200×10-6-2.778×10-6 m2/min respectively, and were related to the change of hot air temperature and humidity. Through SEM observation on the dried peel of ZBM, it was found that the structure of oil bud dried by hot air and hot airinfrared were well preserved, while oil bud was more full after hot airmicrowave drying; and the content of volatile oil extracted from ZBM after hot airmicrowave drying was the most (7.5%) by using GCMS analysis, the relative content of olefins was the largest. The volatile oil extracted from ZBM by hot air drying was the lowest, but the volatile oil had the most kinds of compounds. Considering the quality and drying characteristics of dried Dahongpao ZBM, the hot airinfrared combined drying method was the better method.

Key words: Dahongpao Zanthoxylum bungeanum Maxim, drying kinetics, Weibull function, microstructure, volatile oil

摘要： 为对比大红袍花椒热风干燥、热风—红外与热风—微波联合干燥的特性和品质，揭示对流辐射联合干燥大红袍花椒的干燥过程，指导大红袍花椒生产实践。通过薄层干燥试验，研究三种干燥方式在不同温度(50 ℃、60 ℃、70 ℃)和相对湿度(10%、30%、50%)条件下的干燥曲线和有效水分扩散系数，结合Weibull函数的尺度参数α、形状参数β及估算有效水分扩散系数进行干燥动力学分析，采用扫描电子显微镜(SEM)观察干制花椒油苞结构，提取挥发油进行气相色谱质谱(GCMS)分析。结果表明：热风干燥时间最长，升温降湿有利于提高热风干燥速率、缩短干燥时间，但对热风—红外和热风—微波干燥影响较小；Weibull函数能很好地模拟三种干燥方式，α随干燥条件变化明显，β>1，水分迁移是由物料表面和内部共同控制，估算水分扩散系数变化范围分别为1.303×10-7~2.815×10-7m2/min、7.646×10-7~9.628×10-7m2/min、2.200×10-6~2.778×10-6 m2/min，且与温湿度变化相关；热风干燥和热风—红外干燥能较好地保留花椒油苞，热风—微波干燥花椒油苞更为饱满；热风—微波干燥后花椒挥发油提取量最高(7.5%)，烯烃类物质相对含量最大，热风干燥花椒提取挥发油含量最低，但挥发油中化合物种类最多。热风—红外联合干燥在缩短干燥时间和保持品质方面是较好的选择。

关键词: 大红袍花椒, 干燥动力学, Weibull函数, 微观结构, 挥发油