摘要
为研究马铃薯切片热泵干燥过程中内部水分迁移规律,利用低场核磁共振技术检测横向弛豫时间T2,分析峰面积A2x的变化,建立水分变化动力学模型。结果表明:热泵干燥过程中,提高热风温度能够显著提高干燥速率,加快结合水、不易流动水以及自由水的迁移。干燥过程中自由水和结合水先于不易流动水发生变化,自由水含量在前90 min基本保持不变,之后迅速下降,不易流动水和结合水含量均表现为先升高后降低的趋势。自由水被脱除后,不易流动水和结合水依次达到最大值,随着干燥进行不易流动水逐渐被脱除,随后结合水开始被脱除至干燥结束。马铃薯切片热泵干燥过程属于内部扩散控制,水分有效扩散系数范围为5. 228×10-8～1. 434×10-7m2/s,建立的干燥动力学模型决定系数均大于0. 98,可用于预测马铃薯切片干燥过程中不同状态的水分迁移规律。
In order to study the law of internal water migration in the process of potato chip heat pump drying, the changes of transverse relaxation time T 2 and peak area A 2 x were analyzed by low-field NMR technique, and a dynamic model was established for different states of moisture change in the drying process. The results showed that in the process of heat pump drying, increasing the hot air temperature can significantly increase the drying rate and accelerate the migration rate of bound water, immobilized water and free water. In the drying process, the free and bound water was changed before the immobilized water, and the free water content was remained basically the same for the first 90 min, and then dropped rapidly. The proportions of the immobilized and bound water both showed a rise and then decrease. In the trend, after the free water was removed, the immobilized water and the bound water successively reached a maximum value, and as the drying proceeding, the flowing water was gradually removed, and then the bound water started to be removed until the drying was completed. The heat pump drying process of potato slices belonged to internal diffusion control, and the effective water diffusion coefficient was ranged from 5.228×10^-8m^2 /s to 1.434×10^-7m^2 /s. A dynamic model was established for the changes of moisture content and its content in different stages of potato slice drying with time. The coefficient of determination of all models was greater than 0.98, which was a good predictor of the law of moisture migration of potato slices in different states during the drying process.
作者
朱文学
尤泰斐
白喜婷
刘思佳
侯亚玲
ZHU Wenxue;YOU Taifei;BAI Xiting;LIU Sijia;HOU Yaling(College of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471023, China;Agricultural Product Drying Technology and Equipment of Henan Engineering Technology Research Center, Luoyang 471023, China)
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2018年第12期364-370,共7页
Transactions of the Chinese Society for Agricultural Machinery
基金
河南省高校科技创新团队支持计划项目(17IRTSTHN016)
关键词
马铃薯
干燥
水分迁移
低场核磁共振
数学模型
potato
drying
moisture transfer
low-field nuclear magnetic resonance
mathematical model
