Proton relaxation of waxy and non-waxy rice by low field nuclear magnetic resonance (LF-NMR) to their glassy and rubbery states
Proton relaxation of waxy and non-waxy rice by low field nuclear magnetic resonance (LF-NMR) to their glassy and rubbery states
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DOI：
10.1016/j.jcs.2018.05.014
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发表时间：
2018-07-01
影响因子：
3.8
通讯作者：
Rahman, Mohammad Shafiur
中科院分区：
文献类型：
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作者：
Srikaeo, Khongsak;Rahman, Mohammad Shafiur
利用低场核磁共振（LF-NMR）技术研究了糯和非糯稻米的质子弛豫过程。从弛豫时间上看，质子有3种类型：强结合型（T-2b）、中等结合型（T-21）和弱结合型（T-22）。这些弛豫时间作为温度的函数进行了分析。强束缚质子具有三个临界温度特征。第二临界温度（即当弛豫时间增加后的平台区）被观察到接近DSC玻璃化转变。考虑到弛豫时间作为温度的函数，在T-2b和T-21的情况下观察到一个最大峰，而T-21显示出额外的最小峰。松弛时间T-22没有显示出任何峰值，而非糯性稻米显示出最小峰值，而在糯性稻米的情况下，松弛时间T-22在平台区之后增加。特征弛豫相对相似的情况下，糯性和非糯性大米，而两种大米品种显示出类似的衍射角（20）与不同的强度，通过X射线衍射（XRD）测量。
The proton relaxation of waxy and non-waxy rice was investigated using low field nuclear magnetic resonance (LF-NMR). The relaxation showed 3 types of protons from their relaxation times as strongly-bound (T-2b), moderately-bound (T-21) and weakly-bound (T-22). These relaxation times were analyzed as a function of temperature. The strongly-bound proton showed three characteristics of critical temperatures. The second critical temperature (i.e. when relaxation time increased after a plateau region) was observed as close to the DSC glass transition. Considering relaxation time as a function of temperature, one maximum peak was observed in the case of T-2b and T-21, whereas T-21 showed an additional minimum peak. The relaxation time T-22 did not show any peak, however non-waxy rice showed a minimum peak while it increased after a plateau region in the case of waxy rice. The characteristic relaxations were relatively similar in the cases of waxy and non-waxy rice, while both rice varieties showed similar diffraction angle (20) with different intensities as measured by X-ray diffraction (XRD).