[关键词]
[摘要]
目的 为选择适宜山药片的干燥技术及工艺,将中短波红外干燥、真空脉动干燥、气体射流冲击干燥3种干燥技术用于山药片的干燥,研究分析了不同干燥方式下的山药片干燥动力学和品质。方法 运用3种干燥方法对同一切片厚度为5 mm的山药片进行干燥,研究其水分比、干燥速率随干燥时间的动态变化规律,分析3种干燥方式下的山药片干燥动力学;并对干燥时间、干燥后的色泽、复水比、浸出物、尿囊素含量等指标进行评价。结果 山药片在3种干燥技术下均为降速干燥,其中气体射流冲击干燥时间最短,当干燥温度为70℃、风速为15 m/s时,干燥时间为120 min;真空脉动干燥、中短波红外干燥、气体射流冲击干燥3种干燥方式的水分有效扩散系数分别为7.52×10-10、1.19×10-9、1.30×10-9 m2/s;基于复水比、明亮度、绿红值、蓝黄值、干燥时间、浸出物、尿囊素含量7项指标对3种干燥技术进行了综合评价,中短波红外干燥、真空脉动干燥和气体射流冲击干燥的山药片综合评分分别为0.29、0.59、0.70,气体射流冲击干燥的山药片综合评价最优。结论 在实验参数范围内,3种干燥方式相比,气体射流冲击干燥最适宜于山药片的干燥,干燥时间最短、品质最佳,该研究为探索山药的适宜干燥技术和工艺提供了理论依据。
[Key word]
[Abstract]
Objective In order to explore suitable drying technology for yam slices, the effects of three different drying methods, namely medium and short infrared wave drying, air impingement drying, pulsed vacuum drying, on drying kinetics and quality attributes of yam slices were investigated. Methods The moisture ratio, drying rate curves along with the change of drying time and relationship between dry basis moisture content and drying rate of yam slices were studied under three drying methods. Additionally, the effects of the three drying technologies on color parameters (L*, a*, b*), rehydration ratio, allantoin and extract contents were investigated. Results All drying process of the three drying methods for yam slices belonged to the falling rate period without constant drying stage, and the shortest drying time was only 120 min obtained under air impingement drying temperature of 70℃, air velocity of 15 m/s. The effective moisture diffusivities were 7.52×10-10, 1.19×10-9 and 1.30×10-9 m2/s for pulsed vacuum drying, medium and short infrared wave drying and air impingement drying, respectively. The three drying methods were comprehensively evaluated based on seven indexes including rehydration ratio, drying time, extract and allantoin content, etc. The comprehensive scores of medium and short infrared wave drying, pulsed vacuum drying and air impingement drying were 0.29, 0.59, and 0.70, respectively, which indicated that air impingement drying obtained the highest score. Conclusion Comprehensive evaluation results showed that the best drying method for yam slices drying is air impingement drying and the air impingement. This study provides a theoretical basis for the exploration of suitable drying technology and drying conditions for yam slices dehydration.
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[基金项目]
农业部现代农业产业体系中药材加工机械化(CARS-21);国家重点研发计划项目(2017YFD0400905)