厚度控制对怀山药远红外干燥过程中水分迁移的影响  

Effect of thickness on moisture transfer during Far-infrared drying of Dioscorea opposite

作　　者：周四晴 段续[1,2] 任广跃 张萌[1] 马立 车馨子[1] ZHOU Si-qing;DUAN Xu;REN Guang-yue;ZHANG Meng;MA Li;CHE Xin-zi(College of Food and Bioengineering,Henan University of Science and Technology,Luoyang,Henan 471023,China;Collaborative Innovation Center of Grain Storage Security,Zhengzhou,Henan 450001,China)

机构地区：[1]河南科技大学食品与生物工程学院,河南洛阳471023 [2]粮食储藏安全河南省协同创新中心,河南郑州450001

出　　处：《食品与机械》2019年第12期75-81,共7页Food and Machinery

基　　金：十三五国家重点研发计划（编号：2017YFD0400901）;国家自然科学基金项目（编号：31671907）;智汇郑州·1125聚才计划（编号：2016XT026）

摘　　要：采用远红外干燥设备对鲜怀山药片进行脱水处理,应用低场核磁共振波谱分析和成像分析技术,测定怀山药片干燥过程中的水分状态,综合干燥曲线、干燥速率规律,分析不同切片厚度(4,8,12 mm)的怀山药在干燥过程中的水分扩散特性,并建立薄层干燥模型。结果表明:干燥过程中干燥速率呈现短暂的快速上升后逐渐下降的趋势,4 mm的怀山药达到干燥条件所需时间较8,12 mm的分别短36.33%,53.33%;3种状态水分T2峰面积减小且峰向左移动,干燥过程中自由水耗尽,干燥终点怀山药内部水分主要为结合水(87%)与少量弱结合水(13%);怀山药内部水分存在密度梯度,从高密度向低密度方向迁移,适当减小怀山药厚度可促进H+质子密度下降,提高干燥效率;Page模型拟合效果较好(R^2>0.9),能很好地表征和预测怀山药远红外干燥过程。The water diffusion characteristics of drying dioscorea opposite during by far infrared were investigate.The dehydration of Dioscorea opposite by Far-infrared drying equipment.The technology of low field nuclear magnetic resonance(LF-NMR)and magnetic resonance imaging(MRI)were applied to measured moisture content of D.opposite during drying.Comprehensive consideration results of LF-NMR,MRI,drying curve and drying rate.Water diffusion characteristics of D.opposite with different slice thickness(4,8,and 12 mm)during drying were analyzed,and the thin-layer drying were modeled.The results showed that the drying rate shortly and rapidly increased and then gradually decreased.The drying time of 4 mm thick D.opposite was 36.33%and 53.33%shorter than that of 8 mm and 12 mm respectively.The peak of T2 were moves to the left and its area decreased.Free water was depleted during drying.At the end of drying,the internal moisture of D.opposite was mainly bound water(87%)and a small amount of weak bound water(13%).Water inside of D.opposite has density gradient,and moisture migrated from high to low density zone.Decreasing the thickness of D.opposite properly could promote the decrease of H+proton density and improve the drying efficiency.Page model fitted well(R^2>0.9),it could characterize and predict the process of drying D.opposite by far infrared well.In conclusion,the results provided the theoretical basis for the selection of material thickness and the prediction of drying process of D.opposite.

关 键 词：远红外干燥 低场核磁共振 核磁成像 水分迁移 数学模型 

分 类 号：R28[医药卫生—中药学]