超声功率对铁棍山药超声强化热泵干燥水分迁移的影响  

Effect of Ultrasonic Power on Moisture Migration in Contact Ultrasound Enhanced Heat Pump Drying of Dioscorea opposita

作　　者：薛扬 刘云宏[1,2] 刘恩宠 孙雪 Xue Yang;Liu Yunhong;Liu Enchong;Sun Xue(School of Food and Bioengineering,Henan University of Science and Technology,Luoyang 471000,Henan;Food Green Processing and Quality and Safety Control of Henan Province International Joint Laboratory,Luoyang 471000,Henan)

机构地区：[1]河南科技大学食品与生物工程学院,河南洛阳471000 [2]食品绿色加工与质量安全控制河南省国际联合实验室,河南洛阳471000

出　　处：《中国食品学报》2023年第2期213-222,共10页Journal of Chinese Institute Of Food Science and Technology

基　　金：河南省科技攻关项目(212102110080);河南省高校科技创新人才项目(19HASTIT013)。

摘　　要：为探讨铁棍山药超声强化热泵干燥的水分迁移规律,对山药进行直触超声强化热泵干燥试验,研究超声功率对干燥特性及水分变化的影响。结果表明:在热泵干燥过程中施加超声有利于加快脱水进程。随着超声功率从0 W提高至60 W,干燥时间从630 min缩短至390 min,平均干燥速率由0.0053 g/(g·min)提高到0.0086 g/(g·min),有效水分扩散系数由0.887×10^(-10)m^(2)/s,增大至1.393×10^(-10)m^(2)/s。扫描电镜结果表明:施加超声使物料组织结构变疏松,产生微孔道。随着超声功率的提高,微孔道数量变多,孔隙率变大。低场核磁共振分析表明:铁棍山药中存在自由水、不易流动水和结合水3种状态水,且在干燥过程中其内部水分能够相互转化。自由水的含量不断降低,直至被完全去除;不易流动水的含量在干燥过程中先增高后降低,在干燥结束时仍存在部分不易流动水;结合水的含量在超声强化热泵干燥过程中几乎不变。铁棍山药的核磁共振成像显示,在干燥过程中,物料水分从外到内逐渐流失。提高超声功率能有效加快物料内部水分迁移,促进水分的去除。本研究结果可为果蔬超声强化热泵干燥技术的研发与应用提供参考。To explore the moisture migration law of Dioscorea opposita in contact ultrasound enhanced heat pump drying,this paper used the contact ultrasound enhanced heat pump drying equipment to study the effect of ultrasonic power on drying characteristics and water change.The results showed that applying contact ultrasound during the heat pump drying was beneficial to accelerating the dehydration process.With the increase of ultrasonic power,the drying time of Dioscorea opposita could be shortened from 630 min to 390 min,and the average drying rate could be increased from 0.0053 g/(g·min)to 0.0086 g/(g·min),the range of effective moisture diffusion coefficients was increased from 0.887×10^(-10)m^(2)/s to 1.393×10^(-10) m^(2)/s.Scanning electron microscopy results showed that contact ultrasound could loosen the material structure and produce micropores.With the increase of ultrasonic power,the number of micropores increased and the porosity increased.Low-field nuclear magnetic resonance analysis showed that there were three kinds of moisture in Dioscorea opposita:free water,immobilized water,and bound water.There was mutual migration of internal moisture during the contact ultrasound enhanced heat pump drying process.The content of free water decreased continuously until it was completely removed.The content of immobilized water first increased and then decreased in the drying process,and there was still some immobilized water existence at the end of drying.The content of bound water was almost unchanged during the drying process.The nuclear magnetic resonance imaging of Dioscorea opposita showed that the moisture of the material gradually lost from outside to inside during the drying process.Increasing ultrasonic power during the drying process could accelerate the internal moisture migration rate of Dioscorea opposita and promote the removal of internal moisture.This study could provide a reference for the development and application of contact ultrasound enhanced heat pump drying technology for fruits and vegetabl

关 键 词：干燥 铁棍山药 超声 热泵干燥 水分迁移 

分 类 号：TS215[轻工技术与工程—粮食、油脂及植物蛋白工程]