In order to fully understand the change of moisture content in different positions of tobacco leaves during curing process, and to improve the moisture detection efficiency of tobacco leaf during curing, using the upper leaf of Qinyan96 as test material, Low-field NMR was used to determine the moisture content in lamina and midrib. The results were compared with those determined by a conventional oven method. The results showed that: (1)The map of different positions of tobacco leaves showed that there were 3 states of water in lamina, bound waterT21(0.1-1 ms), semi-bound waterT22(1-10 ms) and free waterT23 (100-1000 ms). There were 2 states of water in midrib, bound waterT21 (1-10 ms) and free waterT22 (100-1000 ms). (2)The inversion spectrum oflamina and midrib has an extremely significant positive correlation with the water mass and moisture content of dry base (the coefficient of determination are in turn 0.9847, 0.9929, 0.9952,P <0.01). (3) Comparing with the conventional oven method, the stability of Low-field NMR was better, which is suitable for rapid and accurate detection of thelamina and midrib moisture content of tobacco leaves during curing.%为全面了解烘烤过程烟叶不同位置水分变化,提高烘烤过程中烟叶水分检测效率,以秦烟96品种上部叶为材料,利用低场核磁共振技术分别对烘烤过程烟叶叶片、主脉水分含量进行检测,并与烘箱法进行对比分析.结果表明:(1)烟叶不同位置弛豫图谱显示,烟叶叶片含有3种状态水分,分别为T21(0.1~1 ms)结合水、T22(1~10 ms)半结合水、T23(100~1000 ms)自由水,烟叶主脉含有2种状态水分,分别为T21(1~10 ms)结合水,T22(100~1000 ms)自由水.(2)烟叶叶片、主脉总信号幅值与其水分质量、干基含水率呈极显著正相关(决定系数R2依次为0.9847、0.9929、0.9952,P<0.01).(3)与烘箱法相比,低场核磁共振法检测稳定性较好,适用于烘烤过程中烟叶叶片和主脉水分的快速、精确检测分析.
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