低场核磁共振技术分析玉米干燥过程中水分的赋存状态  

Variations in Water State of Maize during Drying Based on Low Field-nuclear Magnetic Resonance

作　　者：柯亚婕 徐馨[1] 李鸾玉 魏冬[1] 李玉奇[1] 孙永林[1] KE Yajie;XU Xin;LI Luanyu;VVEI Dong;LI Yuqi;SUN Yonglin(College of Chemical Engineering and Food Science,Hubei University of Arts and Science,Xiangyang 441053)

机构地区：[1]湖北文理学院化学工程与食品科学学院,襄阳441053

出　　处：《食品工业》2018年第11期62-64,共3页The Food Industry

基　　金：中央引导地方科技发展专项(HBWLXYCZ-2017-2);湖北文理学院教师科研能力培育基金(2016zk017);湖北文理学院食品新型工业化学科群建设项目(XKQ08321)

摘　　要：为了解物料在干燥过程中的水分变化,以玉米籽粒为研究对象,采用低场核磁共振技术(LF-NMR)结合干燥曲线,研究在不同的干燥温度下(50℃, 60℃, 70℃, 80℃和90℃),玉米籽粒内部的水分赋存状态及迁移规律。结果表明,玉米主要存在3种状态的水:自由水、半结合水和结合水,对应于3个明显的吸收峰。随干燥时间的延续和温度的升高,各吸收峰均向左迁移且信号幅值变小,核磁锋面积总和显著降低,自由水对应的信号幅值降幅最大,表明干燥温度越高,干燥时间越长,失水越多,而自由水散失的最多。另外,低场核磁总信号面积与干基含水率呈显著的线性关系,因此,在生产实践中,利用核磁共振无损检测可间接测得玉米在干燥过程中的水分含量。To investigate the changes in water of materials during drying, we studied the water storage status and migration characteristics of maize under 50 ℃, 60 ℃, 70 ℃, 80 ℃ and 90 ℃ based on the low field-nuclear magnetic resonance（LF-NMR） combined with drying curves. The results showed that there were three types of water in maize： free water, half-bound water and bound water, corresponding to three obvious absorption peaks. With prolonged drying and increased temperature, all absorption peaks moved to the left, the signal amplitude decreased, and the total area of nuclear magnetic front significantly reduced, accompanied by the largest loss in the free water. The results suggested that the higher the drying temperature and the longer the drying time, the more water loss, and free water loss the most. In addition, there was a significant linear relationship between the total area of the low field nuclear magnetic field and the dry base moisture content. Thence, in the production practice, the water content of maize during drying could be measured indirectly by NMR.

关 键 词：核磁共振 热风干燥 水分状态 玉米 

分 类 号：O657.2[理学—分析化学] TS213.4[理学—化学]