1H NMR studies of starch-water interactions during microwave heating
1H NMR studies of starch-water interactions during microwave heating
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DOI：
10.1016/j.carbpol.2013.05.021
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发表时间：
2013-09-12
影响因子：
11.2
通讯作者：
Chen, Wei
中科院分区：
文献类型：
--
作者：
Fan, Daming;Ma, Shenyan;Chen, Wei
研究了微波加热对淀粉糊化过程中水分分布和动态的影响。采用H-1核磁共振（H-1 NMR）对微波加热、快速常规加热和常规加热后的淀粉进行了测定，测定了水活度为0.686的大米淀粉颗粒中的水分分布和动态。利用反转恢复（IR）和carr - purcell - meiboomm - gill （CPMG）脉冲序列测定了系统质子的纵向和横向弛豫时间。结果表明：在40 ~ 60℃的温度范围内，三种加热方式处理的样品中，T-1长组分和T-1短组分呈现出两个明显的光谱峰，随着温度的升高，T-1长组分和T-1短组分相互接近，呈现逐渐收敛的趋势，而T-2在整个温度范围内呈现单峰。此外，在微波加热、快速常规加热和常规加热的样品中，水分子的T-1和T-2存在显著差异。结果表明，微波的快速加热作用抑制了淀粉和水分子之间氢键的破坏。相反，微波加热引起极性分子的振动运动加速了氢键的破坏，产生的效果比微波的快速加热效果强得多。(C) 2013 Elsevier Ltd.版权所有。
The aim of the present study was to investigate the effect of microwave heating on water distribution and dynamics in starch granules during the gelatinization of starch. Starch samples treated with microwave heating, rapid conventional heating and conventional heating was measured by H-1 NMR to examine the water distribution and dynamics in rice starch granules at a water activity of 0.686. The system proton longitudinal and transverse relaxation times were determined using inversion recovery (IR) and Carr-Purcell-Meiboom-Gill (CPMG) pulse sequences. The results showed that the T-1 of the water molecules in the samples treated with any of the three heating methods exhibited two distinct spectral peaks over the temperature range of 40-60 degrees C. With rising temperature, the long T-1 component and the short T-1 component approached each other, showing a trend of gradual convergence, while T-2 exhibited a single peak over the entire temperature range examined. In addition, significant differences were observed in the T-1 and T-2 of the water molecules in the samples heated by microwave, rapid conventional and conventional. The results show that the rapid heating effect of microwave inhibits the destruction of the hydrogen bonds between starch and water molecules. In contrast, the vibration motion of polar molecules caused by microwave heating accelerates the destruction of hydrogen bonds, producing a much stronger effect than the rapid heating effect of microwave. (C) 2013 Elsevier Ltd. All rights reserved.