Kinetic and mechanistic considerations in the gelation of genipin-crosslinked gelatin
Kinetic and mechanistic considerations in the gelation of genipin-crosslinked gelatin
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DOI：
10.1016/j.ijbiomac.2006.04.010
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发表时间：
2006-11-15
影响因子：
8.2
通讯作者：
Paulson, A. T.
中科院分区：
文献类型：
--
作者：
Nickerson, M. T.;Patel, J.;Paulson, A. T.
研究了10%（w/w）明胶溶胶的胶凝性质（胶凝时间（t（凝胶））和凝胶强度）作为京尼平（GP）浓度（0-15 mM）和温度（25-55 ℃）的函数，以辨别固定的机制和最佳条件。凝胶时间随温度的升高而增加，达到最大值，然后随温度的进一步升高而下降。相比之下，网络强度数据则呈现相反的趋势。从t（凝胶）和网络强度的热行为，可以推断，在低温制度的凝胶化是由氢键为主，而在高温制度，它是由共价交联为主。在较高的温度下，交联描述的阿克里乌斯速率定律表达式，与63.2和67.8 kJ/mol之间的活化能，取决于GP浓度。在低温状态下，在10和15 MM GP的存在下，Arrhenius图分别导致-75.8和-64.4 kJ/mol的负活化能。随着GP浓度和温度的增加，明胶网络逐渐从氢键（物理交联）为主转变为共价交联（化学交联）。(c)2006 Elsevier B. V.保留所有权利。
The gelling properties (gel time (t(gel)) and gel strength) of a 10% (w/w) gelatin sol were investigated as a function of genipin (GP) concentration (0-15 mM) and temperature (25-55 degrees C) to discern mechanisms and optimal conditions for fixation. Gel time increased with increasing temperature, reached a maximum, and then declined as temperature was raised further. By contrast, network strength data followed the opposite trend. From the thermal behavior of t(gel) and network strength, it was inferred that gelation in the low-temperature regime was dominated by hydrogen bonding, while in the high-temperature regime it was dominated by covalent crosslinking. At higher temperatures, crosslinking was described by an Arrhenius rate law expression, with activation energies between 63.2 and 67.8 kJ/mol, depending on GP concentration. In the low temperature regime, an Arrhenius plot resulted in negative activation energies of -75.8 and -64.4 kJ/mol in the presence of 10 and 15 MM GP, respectively. With an increase in both GP concentration and temperature, the gelatin network gradually shifted from being dominated by hydrogen bonds (physical crosslinks) to covalent crosslinking (chemical crosslinks). (c) 2006 Elsevier B.V. All rights reserved.