玉米淀粉与黄原胶复配体系流变和凝胶特性分析

为考察胶体对淀粉流变及凝胶特性的影响，该文以玉米淀粉为原料，加入不同比例黄原胶，研究两者复配后流变及凝胶特性的变化，对其相互作用机理进行了初步探讨。结果表明，玉米淀粉及两者复配体系属于屈服-假塑性流体，随着黄原胶比例的提高，复配体系的稠度系数显著增加，流体指数降低，假塑性增强，但黄原胶比例大于10%时，增加不再显著。动态流变学试验显示，复配体系具有更为优越的黏弹性，黄原胶可与淀粉分子间相互作用形成氢键，使得分子链段间的缠结点增加，同时，可延缓及阻止部分直链淀粉分子间的重新排列，从而抑制淀粉凝胶体系的回生，复配体系形成了质地更为柔软的凝胶。综合考虑，在实际应用中选择玉米淀粉与黄原胶质量比为9.0∶1.0 (g/g)较为适宜。研究结果可为更好的在食品工业中应用玉米淀粉/黄原胶复配体系及品质控制提供理论依据。

Rheological and gel properties of corn starch-xanthan mixed systems

In order to investigate the effects of hydrocolloid on the rheological and gel properties of starch paste, this paper characterized the rheolgical and gel behaviors of corn starch and corn starch/xanthan gum mixed systems. The mechanism of interaction between corn starch and xanthan gum was also analyzed. The results showed that corn starch and corn starch/xanthan gum mixed pastes were the typic yield-pseudoplasticity. A significant synergistic effect on consistency index was evident. The flow behavior index of mixed pastes was increased as the ratio of xanthan gum in the mixtures was raised. The mixture pastes exhibited more pseudoplasticity., but the effect was no pronounced as the proportion of xanthan gum was greater than 10%.The dynamic oscillatory test showed that the mixture pastes had a more superior viscoelastic property. The xanthan gum molecules exerted intermolecular interactions with the amylose molecules by hydrogen bond. The short-term retrogradation of amylose was prolonged and restricted by the present of xanthan gum. The mixed gels were more softer. Based on an overall consideration, a 9.0:1.0 (w/w) mixture of corn starch and xanthan gum proved to be the optimal additive. The research results will provide a theoretical basis for application and quality control of corn starch/xanthan gum mixed system in food industry.