图8 根据Arrhenius方程，表观速率常数k与反向脱乙酰化温度T的对数图，其中k=A exp（-Ea/RT）

图9 KGM在溶液中的脱乙酰化和溶胶-凝胶转变机理示意图

综上所述，可通过如图9描述的来表达以氢氧化钠为催化剂的KGM水溶液的脱乙酰化和凝胶化机理。首先，来自氢氧化钠的OH-攻击了KGM大分子链的乙酰基，并迅速脱乙酰化以暴露出链上更多的羟基。其次，羟基之间的氢键相互作用和KGM大分子链之间的疏水相互作用使大分子链以有序的方式聚集和重组。最后，大分子链的有序重组导致溶胶-凝胶转变并形成水凝胶。

2.4 结论 为了阐明脱乙酰基对KGM凝胶溶液形成的影响，以氢氧化钠为催化剂，采用傅里叶变换红外光谱（FTIR）和 X射线衍射（WAXRD）对KGM凝胶进行表征，并采用稳态荧光技术研究了KGM在稀碱性溶液中溶胶-凝胶相转变过程中的脱乙酰动力学，发现KGM溶液的浓度、pH值和温度对脱乙酰反应有较大影响，根据第一反应模型，3 g/L KGM溶液在 pH 10时的脱乙酰活化能约为83.1 kJ/mol。 这些结果将有助于了解KGM凝胶化过程中的初始结构变化和凝胶化机理。

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[1] Kato K, Matsuda K. Studies on the Chemical Structure of Konjac Mannan Part I. Isolation and Characterization of Oligosaccharides from the Partial Acid Hydrolyzate of the Mannan [J]. Agric Biol Chem, 1969, 33： 1446-1453.

[2] Maeda M, Shimahara H, Sugiyama N. Detailed Examination of the Branched Structure of Konjac Glucomannan [J]. Agric Biol Chem, 1980, 44(2)： 245-252. DOI： 10.1080/.

[3] Katsuraya K, Okuyama K, Hatanaka K, et al. Constitution of Konjac Glucomannan： Chemical Analysis and 13C NMR Spectroscopy [J]. Carbohyd Polym, 2003, 53(2)： 183-189. DOI： 10.1016/S0144-8617(03)00039-0.

[4] Chen HL, Cheng HC, Liu YJ, et al. Konjac Acts as a Natural Laxative by Increasing Stool Bulk and Improving Colonic Ecology in Healthy Adults [J].Nutrition, 2006, 22(11-12)： 1112-1119. DOI： 10.1016/

[5] Vuksan V, Sievenpiper JL, Owen R, et al. Beneficial Effects of Viscous Dietary Fiber from Konjac-mannan in Subjects with the Insulin Resistance Syndrome：Resultsof a Controlled Metabolic Trial. Diabetes Care, 2000,23(1)： 9-14. DOI： 10.2337/

[6] Huang YC, Chu HW, Huang CC, et al. Alkali-treated Konjac Glucomannan Film as a Novel Wound Dressing [J]. Carbohyd. Polym, 2015, 117： 778-787. DOI： 10.1016/

[7] Huang YC, Yang CY, Chu HW, et al. Effect of Alkali on Konjac Glucomannan Film and its Application on Wound Healing [J]. Cellulose,2015, 22(1)： 737-747.

[8] Liu P, Yang YH, Liu Y, et al. Konjac Glucomannan Supported Palladium Complex： an Efficient and Recyclable Catalyst for Heck Reaction [J]. React Funct Polym, 2008, 68(1)： 384-388. DOI： 10.1016/

[9] Zhao XG, Li J, Jin WP, et al. Preparation and Characterization of a Novel pH-response Dietary Fiber： Chitosan-coated Konjac Glucomannan [J]. Carbohyd. Polym., 2015, 117(1)： 1-10. DOI： 10.1016/

[10] Chen ZG, Zong MH, Li GJ. Lipase-catalyzed Acylation of Konjac Glucomannan in Organic Media [J]. Process Biochem, 2006, 41(7)： 1514-1520. DOI： 10.1016/

[11] Zhang C, Chen JD, Yang FQ. Konjac Glucomannan, a Promising Polysaccharide for OCDDS [J]. Carbohyd Polym, 2014, 104： 175-181. DOI：10.1016/

[12] Liang HS, Ye T, Zhou B, et al. Fabrication of Gastric Floating Controlled Release Tablet Based on Konjac Glucomannan [J]. Food Res Int, 2015, 72：47-53. DOI： 10.1016/

[13] Xu DY, Li GJ, Liao ZF, et al. Synthesis and Characterization of a Novel pH-sensitive Complex for Drug Release [J]. Journal of Wuhan University of Technology-Materials Science Education, 2010, 25(1)： 24-27. DOI：10.1007/s-010-1024-9.

[14] Huang L, Takahashi R, Kobayashi S, et al. Gelation Behavior of Native and Acetylated Konjac Glucomannan. Biomacromolecules, 2002, 3(6)： 1296-1303. DOI： 10.1021/bm0.

[15] Pan ZD, Meng JJ, Wang YM. Effect of Alkalis on Deacetylation of Konjac Glucomannan in Mechano-chemical Treatment [J]. Particuology, 2011,9(3)： 265-269. DOI： 10.1016/

[16] Balint K, Stephen PM. Synthesis of Acetylated Konjac Glucomannan and Effect of Degree of Acetylation on Water Absorbency [J].Biomacromolecules, 2001, 2(3)： 824-826. DOI： 10.1021/bm0c.

[17] Gao SJ, Nishinari K. Effect of Degree of Acetylation on Gelation of Konjac Glucomannan [J]. Biomacromolecules, 2004, 5(1)： 175-185. DOI： 10.1021/bm0f.

[18] Vieira MC, Gil AM. A Solid State NMR Study of Locust Bean Gum Galactomannan and Konjac Glucomannan Gels [J]. Carbohyd. Polym, 2005,60(4)： 439-448. DOI： 10.1016/,

[19] Zhang H, Yoshimura M, Nishinari K, et al. Dynamic Viscoelastic Study on the Gelation of Konjac Glucomannan with Different Molecular Weights [J]. Food Hydrocolloids, 2001, 59(1)： 38-59. DOI：10.1002/1097-0282()59：1

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