阶段降湿对山药热风干燥特性和品质的影响  

Influence of step-down relative humidity on drying characteristic and quality of hot air drying of Dioscoreae Rhizoma slices

作　　者：巨浩羽 赵士豪[1] 赵海燕 张卫鹏 高振江[2] 肖红伟[2] JU Hao-yu;ZHAO Shi-hao;ZHAO Hai-yan;ZHANG Wei-peng;GAO Zhen-jiang;XIAO Hong-wei(College of Bioscience and Engineering,Hebei University of Economics and Business,Shijiazhuang 050061,China;College of Engineering,China Agricultural University,Beijing 100083,China;College of Business Administration,Hebei University of Economics and Business,Shijiazhuang 050061,China;College of Artificial Intelligence,Beijing Technology and Business University,Beijing 100048,China)

机构地区：[1]河北经贸大学生物科学与工程学院,河北石家庄050061 [2]中国农业大学工学院,北京100083 [3]河北经贸大学工商管理学院,河北石家庄050061 [4]北京工商大学人工智能学院,北京100048

出　　处：《中草药》2021年第21期6518-6527,共10页Chinese Traditional and Herbal Drugs

基　　金：北京市自然科学基金项目(6204035);北京市教委组织部优秀人才项目(2018000020124G034);河北省自然科学基金资助项目(C2020207004);河北省高等学校科学技术研究项目(QN2021054);河北经贸大学校级教学研究项目(2020JYY47);河北经贸大学“生物工程”专项项目(2021SGYB03)。

摘　　要：目的探索阶段降湿中高湿保持时间及不同降湿工艺对山药热风干燥特性和品质的影响,为提高山药干燥效率和品质及揭示相对湿度的调控依据提供理论基础。方法研究干燥温度60℃,风速3.0 m/s,相对湿度恒定10%、50%保持不同时间(5、10、20 min)后降为10%、以及相对湿度50%保持10 min后不同降湿干燥工艺(直接降为10%、20%保持20 min后降为10%、30%,20 min,20%,20 min后降为10%、40%,20 min,30%,20 min,20%,20 min后降为10%),山药片的干燥特性、水分有效扩散系数(D_(eff))、色泽、复水比、能耗、多糖含量和微观组织结构。结果高相对湿度不同保持时间下,相对湿度50%保持10 min相对于恒定10%干燥条件下,干燥时间缩短了20.0%;干燥过程分为升速和降速2个阶段;在10 min时,山药片被充分预热,温度升至45.8℃。不同降湿干燥工艺下,相对湿度50%保持10 min后,阶梯降至10%相对于直接降为10%的干燥条件,干燥时间缩短了25.0%;干燥过程同样分为升速和降速2个阶段;物料温度整体上呈现出缓慢上升的趋势,且均大于其余3者同时期的物料温度;D_(eff)先慢后快,整个干燥过程平均D_(eff)最大,为6.77×10^(−10) m^(2)/s;此干燥条件下明亮度(L*)、复水比和多糖含量分别达到其最大值,为(90.76±0.12)、(2.36±0.08)、(57.32±0.21)mg/g,能耗达最低值,为(2.98±0.06)kW·h/kg,且内部形成较明显的水分扩散迁移孔道。结论高相对湿度有助于强化对物料的传热作用,保持时间应当以物料充分预热为判定依据;阶段降湿干燥过程中,降低相对湿度应当以不降低物料温度为基本约束条件;山药片的恒温阶段降湿干燥过程中,干制后的色泽、复水性、能耗和多糖含量均与干燥时间直接相关;高相对湿度有助于保持和形成物料内部的多孔结构,有助于水分的扩散迁移;依次阶段降湿的干燥方式有助于提高山药片的干燥效率和品质,为山药热风干燥过程中如�Objective In order to improve the drying efficient and quality of Dioscoreae Rhizoma slices and reveal the relative humidity(RH)control principle,the influence of different keeping time of high RH and different dehumidification humidity process on drying characteristic and quality of hot air drying of Dioscoreae Rhizoma slices were investigated.Methods With drying temperature 60 oC and air velocity 3.0 m/s,the influence of constant 10%RH,different 50%RH keeping time(5,10,and 20 min)then decreasing to 10%as well as different dehumidification RH when 50%was kept 10 min(decreased to 10%directly;20%,20 min then 10%;30%,20 min,20%,20 min then 10%;40%,20 min;30%,20 min;20%,20 min then 10%)on drying characteristic,moisture effective diffusion coefficient(D_(eff)),color value,rehydration ratio,energy consumption,polysaccharide content and microstructure were studied.Results Under different high RH keeping time,when RH 50%was kept for 10 min and then decreased to 10%,the drying time was shorted by 20.0%compared to constant 10%RH drying condition.The drying process was divided into increasing and decreasing drying rate stage.The Dioscoreae Rhizoma slices were fully preheated and the temperature rose to 45.8 oC at 10 min.Under different dehumidification RH drying conditions,when 50%RH was kept for 10 min and then decreased to 10%successively,the drying time was shorted by 25.0%compared to when 50%RH was kept for 10 min and then decreased to 10%.The drying process was also divided into increasing and deceasing drying rate stage.On the whole,the material temperature showed a slow rising trend and was more than the other three drying conditions at the same time.D_(eff) was slow at first and then became quick and the average D_(eff) was the largest as to be(6.77×10^(−10))m^(2)/s.The brightness value(L*),rehydration ratio(RR)and polysaccharide content were all achieved their maximum value as to be(90.76±0.12),(2.36±0.08),and(57.32±0.21)mg/g,respectively.At the same time,the energy consumption achieved its minimum value as

关 键 词：热风干燥 山药 相对湿度 阶段降湿 多糖 微观结构 水分有效扩散系数 复水比 能耗 

分 类 号：R283.6[医药卫生—中药学]