Effects of glycerol on the molecular mobility and hydrogen bond network in starch matrix
Effects of glycerol on the molecular mobility and hydrogen bond network in starch matrix
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DOI：
10.1016/j.carbpol.2014.08.105
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发表时间：
2015-01-22
影响因子：
11.2
通讯作者：
Ludescher, Richard D.
中科院分区：
文献类型：
--
作者：
Liang, Jun;Ludescher, Richard D.
使用磷光和红外光谱研究了甘油对无定形玻璃状淀粉基质中分子流动性和氢键网络的影响。通过将水性马铃薯淀粉凝胶（5%，w/v）与相应含量的甘油快速脱水，配制出含有不同量甘油（0、5、10、20和30重量%）的无定形马铃薯淀粉膜； X射线衍射数据证实薄膜含有可忽略的结晶淀粉含量。赤藓红 B (Ery B) 磷光用于监测这些基质在 0 至 100 摄氏度温度范围内的分子迁移率。对 Ery B 发射峰频率、带宽和强度衰减的分析提供了有关基质中分子迁移率热激活模式的信息。添加甘油增强了 Ery B 三线态周围的偶极弛豫，并且弛豫程度在低温和中温下增加，但在较高温度下下降。对于纯淀粉，该转变的取决于甘油含量的起始温度为 70 摄氏度，而对于含有 30% 甘油的基质，则降至 40 摄氏度。对 Ery B 三重态非辐射衰变速率的测量表明，甘油对淀粉基质的塑化程度接近 10 wt.%，同时充当抗塑剂以在较低含量下增加基质分子迁移率。这些基质特性与通过红外测量的甘油依赖性氢键强度增加有关。 (C) 2014 Elsevier Ltd. 保留所有权利。
The effects of glycerol on molecular mobility and hydrogen bonding network in an amorphous glassy starch matrix were studied using phosphorescence and IR spectroscopy. Amorphous potato starch films containing varying amounts of glycerol (0, 5, 10, 20 and 30 wt.%) were formulated by rapidly dehydrating aqueous potato starch gel (5%, w/v) with a corresponding content of glycerol; X-ray diffraction data confirm that the films contained negligible content of crystalline starch. Erythrosin B (Ery B) phosphorescence was used to monitor the molecular mobility of these matrices over the temperature range from 0 to 100 degrees C. Analysis of Ery B emission peak frequency, band width and intensity decay provided information about thermally-activated modes of molecular mobility in the matrix. Dipolar relaxation around the triplet state of Ery B was enhanced by addition of glycerol and the extent of relaxation increased at low and intermediate but decreased at higher temperature. The glycerol content-dependent onset temperature for this transition was 70 degrees C for pure starch and decreased to 40 degrees C for a matrix with 30% glycerol. Measurements of the rate of non-radiative decay from the Ery B triplet state indicated that glycerol plasticized the starch matrix above similar to 10 wt.% while acting as an antiplastizer to increase the matrix molecular mobility at lower content. These matrix properties were related to glycerol-dependent increases in hydrogen bond strength as measured by IR. (C) 2014 Elsevier Ltd. All rights reserved.