Centre for Water Soluble Polymers, Glyndwr University, Plas Coch, Mold Road, Wrexham LL11 2AW, UK.
Carbohydr Polym. 2013 Feb 15;92(2):1018-25. doi: 10.1016/j.carbpol.2012.10.049. Epub 2012 Oct 27.
The interaction of native xanthan gum, deacetylated xanthan gum and depyruvated xanthan gum with konjac glucomannan has been studied using DSC and controlled stress rheometry. In the absence of electrolyte the DSC cooling curves for native xanthan and deacetylated xanthan showed a single peak and there was a corresponding sharp increase in the storage modulus indicating gel formation. It is apparent that on cooling, association of the konjac glucomannan with the native xanthan molecules is triggered by the xanthan coil-helix transition. In the presence of electrolyte, there were two DSC peaks observed. The higher temperature DSC peak was attributed to the xanthan coil-helix transition while the lower temperature DSC peak was attributed to konjac glucomannan-xanthan association as noted by an increase in the storage modulus. The gels formed were much weaker than those in the absence of electrolyte. The DSC cooling curves for depyruvated xanthan in the absence of electrolyte showed two peaks. The higher temperature peak was attributed to the coil-helix transition while the lower temperature peak corresponded to gelation as noted by an increase in the storage modulus. The gels were very much weaker than for native xanthan gum and deacetylated xanthan gum.
使用 DSC 和控制应变速率流变仪研究了天然黄原胶、脱乙酰黄原胶和脱吡喃醛黄原胶与魔芋葡甘聚糖的相互作用。在没有电解质的情况下，天然黄原胶和脱乙酰黄原胶的 DSC 冷却曲线显示出单个峰值，并且存储模量相应急剧增加，表明形成凝胶。显然，在冷却时，由于黄原胶的螺旋-卷曲转变，魔芋葡甘聚糖与天然黄原胶分子发生缔合。在存在电解质的情况下，观察到两个 DSC 峰。较高温度的 DSC 峰归因于黄原胶的螺旋-卷曲转变，而较低温度的 DSC 峰归因于魔芋葡甘聚糖-黄原胶的缔合，这可以通过存储模量的增加来证明。形成的凝胶比没有电解质时弱得多。在没有电解质的情况下，脱吡喃醛黄原胶的 DSC 冷却曲线显示出两个峰。较高温度的峰归因于螺旋-卷曲转变，而较低温度的峰对应于凝胶化，这可以通过存储模量的增加来证明。凝胶比天然黄原胶和脱乙酰黄原胶弱得多。
