AgroSup, Dijon EMMA team 1 Esplanade Erasme, 21000 Dijon, France.
Carbohydr Res. 2010 May 7;345(7):929-33. doi: 10.1016/j.carres.2010.02.015. Epub 2010 Feb 19.
Calcium and zinc pectinate gels were prepared using a method which allowed calcium or zinc to diffuse from the cross-linking solution through a dialysis membrane to form a gel with amidated low-methoxyl pectin. The gel thus obtained was then dried, and the film structure was studied using FTIR spectroscopy as a function of the cation content (0%, 5%, 10%, and 15% w/v). Important consideration was given to the three functional groups (amide, carboxyl ester, and carboxylate groups) present in the pectin. When the zinc content was increased, the three wavenumber values corresponding to these three functional groups did not change significantly, while for calcium pectinate, the three wavenumber values were shifted profoundly when the amount of calcium ions changed. These results confirm that calcium ions could form stable interactions with carboxylate groups as described by the eggbox model [Grant, G.T.; Morris, E.R.; Rees, D.A.; Smith, P.J.C.; Tho, D. FEBS Lett.1973, 32, 195-198] while the lower coordination number of zinc does not permit a structured gel to develop.
钙锌果胶凝胶是采用一种方法制备的，该方法允许钙或锌从交联溶液中通过透析膜扩散，以形成与酰胺化低甲氧基果胶的凝胶。然后将得到的凝胶干燥，并使用傅里叶变换红外光谱法（FTIR）研究其膜结构，作为阳离子含量（0％，5％，10％和 15％w/v）的函数。在果胶中存在的三个功能团（酰胺基，羧酸酯基和羧酸盐基）受到了重要考虑。当锌含量增加时，与这三个功能团相对应的三个波数值没有明显变化，而对于钙果胶，当钙离子的量发生变化时，三个波数值会发生深刻变化。这些结果证实，正如鸡蛋盒模型[Grant，G.T.；莫里斯，E.R.；里斯，D.A.；史密斯，P.J.C.；Tho，D.FEBS Lett.1973，32，195-198]所述，钙离子可以与羧酸盐基形成稳定的相互作用，而锌的较低配位数则不允许形成结构化凝胶。
