干燥方式对黄精片干燥特性和微观结构的影响

为探究不同干燥方式对红花滇黄精(Polygonatum kzngzanum Coll.et Hemsl.,以下简称“黄精”)片干燥特性和微观结构的影响，优选黄精片的最适干燥方式，采用真空冷冻干燥(Vacuum Freeze Drying，VFD)、热风干燥(Hot Air Drying，HAD)、真空干燥(Vacuum Drying，VD)、微波干燥(Microwave Drying，MD) 4种干燥方式，以干燥时间、平均干燥速率、有效水分扩散系数、色泽、收缩率、复水比、单位能耗以及微观结构为指标进行评价。结果表明：微波干燥下的黄精片干燥时间及单位能耗分别为131 min、5.78 (kW·h)/kg，均显著低于其他干燥方式；微波干燥样品的平均干燥速率及有效水分扩散系数分别为0.025 84 g/(g·min)、6.49×10^-10 m²/s,均显著高于其他干燥方式；微波干燥样品的L^*值(76.40)、收缩率(69.42%)、复水比(4.39 g/g)和微观结构均接近真空冷冻干燥样品，显著高于热风和真空干燥样品。综合考虑产品质量、干燥效果及加工成本，建议将微波干燥作为黄精片高效优质的脱水手段。

Effects of Drying Methods on Drying Characteristics and Microstructure of Polygonatum kzngzanum Coll.et Hemsl.Slices

In order to explore the effects of different drying methods on the drying characteristics and microstructure of Polygonatum kzngzanum Coll.et Hemsl.slices,and to optimize the optimal drying method of P. kzngzanum Coll.et Hemsl.slices,four drying methods including Vacuum Freeze Drying (VFD),Hot Air Drying (HAD),Vacuum Drying (VD),and Microwave Drying (MD)were used.The drying time,average drying rate,effective moisture diffusion coefficient,color,shrinkage rate,rehydration ratio,unit energy consumption and microstructure were used as indicators to evaluate.The results showed that under microwave drying,the drying time and energy consumption of P. kzngzanum Coll.et Hemsl.slices were 131 min and 5.78 (kW·h)/kg,respectively,which were significantly lower than those of other drying methods.The average drying rate and effective moisture diffusion coefficient of microwave drying samples were 0.025 84 g/(g·min) and 6.49×10^-10m²/s,respectively,which were significantly higher than those of other drying methods.The L^* value (76.40),shrinkage rate (69.42%),rehydration ratio (4.39 g/g),and microstructure of microwave drying samples were similar to those of vacuum freeze-drying samples,which were significantly higher than those of hot air and vacuum drying samples. Considering the product quality,drying efficiency,and processing costs,it is recommended to use microwave drying as an efficient and high-quality dehydration method for P. kzngzanum Coll.et Hemsl.slices.