分子量、脱乙酰度与浓度对壳聚糖流变性影响

Effect of Molecular Weight,Degree of Deacetylation and Concentration on Rheological Properties of Chitosan

壳聚糖在食品工业中常作为被膜剂使用,其流变性能是被膜过程的关键因素。该研究对不同分子量、脱乙酰度和浓度的壳聚糖溶液流变行为在0～300 s^(-1)剪切速率下进行考察,结果表明壳聚糖溶液的流变曲线呈闭合型滞后回路,滞后面积小,回复性强。壳聚糖黏度随分子量与浓度的提高及脱乙酰度的下降呈现上升趋势。在较低分子量和浓度下,壳聚糖溶液呈现剪切变稠特性,提高浓度与分子量会促使溶液从胀塑性流体向假塑性流体的转变。

Chitosan is widely used as a coating agent in food industry, and its rheological properties are a key factor in the coating process. The rheological behaviors with shear rates of 0-300 s-1 of chitosan film-forming solution with different molecular weights, degree of deacetylation and concentration were considered. The results showed that chitosan solution exhibited closed hysteresis loops with a small lagging area indicating a strong recovery capacity. The viscosity of chitosan increased with the increase of molecular weight and concentration and the decrease of degree of deacetylation. At lower molecular weight and concentration, the chitosan film-forming solution exhibited shear thickening characteristics. Increasing the concentration and molecular weight would promote the transition of the film-forming solution from the dilatant fluid to pseudoplastic fluid.