青香蕉微波干燥特性及动力学模型研究  

Research on Microwave Drying Characteristics and Kinetic Model of Green Bananas

作　　者：沈素晴 徐亚元 李大婧[2] 张钟元[2] 肖亚冬 聂梅梅 刘春菊[2] 郑铁松[1] SHEN Suqing;XU Yayuan;LI Dajing;ZHANG Zhongyuan;XIAO Yadong;NIE Meimei;LIU Chunju;ZHENG Tiesong(School of Food and Pharmaceutical Engineering,Nanjing Normal University,Nanjing 210097,China;Institute of Agricultural Products Processing,Jiangsu Academy of Agricultural Sciences,Nanjing 210014,China)

机构地区：[1]南京师范大学食品与制药工程学院,江苏南京210097 [2]江苏省农业科学院农产品加工研究所,江苏南京210014

出　　处：《食品工业科技》2022年第14期110-117,共8页Science and Technology of Food Industry

基　　金：江苏省青年基金项目(BK20180307)。

摘　　要：为探究青香蕉微波干燥过程中的水分扩散特性,通过开展青香蕉微波干燥试验,考察了青香蕉在不同微波功率密度(3、5、7、9 W/g)下干燥特性,建立了青香蕉微波干燥试验模型;利用低场核磁共振技术(low-field nuclear magnetic resonance,LF-NMR)考察了干燥过程中青香蕉内部水分分布状态与变化规律。结果表明,青香蕉微波干燥过程中干燥速率呈现先上升后下降的趋势;有效扩散系数在1.082×10^(−8)~7.708×10^(−8) m^(2)/s之间,并随着微波功率密的升高而增大。核磁共振试验表明干燥过程中,自由水最先被去除,不易流动水整体呈现先上升后下降的趋势,结合水整体呈上升趋势;随着微波干燥的时间延长,三种状态水分峰面积减小且总峰向弛豫时间减少的方向移动,干燥结束时,青香蕉中的自由水基本被去除,内部水分主要以结合水和不流动水状态存在。通过对青香蕉干燥动力学模型拟合发现,Page模型拟合度较高(R2>0.9),可为有效描述青香蕉微波干燥过程中水分随时间的变化规律提供依据。In order to explore the water diffusion characteristics of green bananas during the microwave drying process,a microwave drying test was conducted to investigate the green bananas drying characteristics under different microwave power densities(3,5,7 and 9 W/g),and the microwave drying test model of green bananas was established.Low-field nuclear magnetic resonance(LF-NMR)was used to investigate the internal moisture distribution and change law of green bananas during the drying process.Results showed that drying rate of green bananas in the microwave drying process increased first and then decreased,the effective diffusion coefficient was between 1.082×10^(−8) and 7.708×10^(−8) m^(2)/s,and also increased with the increasing of microwave power density.The nuclear magnetic resonance experiments showed that,during the drying process,the free water was removed first,the non-flowing water showed an overall upward trend and then a downward trend,while the combined water showed an overall upward trend.With the extension of microwave drying time,the water peak area of the three states decreased and the total peak moved in the direction of the decrease of relaxation time,at the end of drying,the free water in green banana was basically removed,and the internal water mainly existed in the state of combined water and non flowing water.By fitting green banana drying kinetics model,it was found that the Page model fitted best(R2>0.9),which could provide a basis for effectively describing the variation law of water with time during the microwave drying process of green bananas.

关 键 词：青香蕉 微波干燥 有效水分扩散系数 低场核磁 干燥动力学模型 

分 类 号：TS255[轻工技术与工程—农产品加工及贮藏工程]