淀粉直/支比对高酯果胶凝胶性质的影响

Influence of Amylose/Amylopectin Ratio of Starch on the Gel Property of Pectin

采用流变仪和质构仪考察淀粉的直/支比对高酯果胶凝胶性质的影响。动态流变学测试结果表明:随着直链淀粉比例的增加,凝胶体系的储能模量和损耗模量值升高,损耗因子降低,体系表现出更为优越的黏弹性。静态流变测试结果表明:随着直链淀粉比例的增加,凝胶体系的稠度系数K值增加,流体指数n降低,触变环面积增大,形成的三维网络凝胶结构致密。质构测试结果表明:随着直链淀粉比例的增加,凝胶体系的硬度、内聚性和黏着性均显著增加。相互作用力的测定结果表明:淀粉与果胶之间通过氢键发生相互作用。

Influence of different amylose/amylopectin ratio of starch on the gel property of high methoxyl pectin were studied by using an oscillatory rheometer and Texture Profile Analysis.Dynamic rheological studies suggested that as the proportion of amylose increased,the G′and G″values of the mixed gel increased,the tanδdecreased,and gave rise to better viscoelasticity.In static rheological studies,pectin gel remained pseudo-plastic fluids despite the presence of starch,and in the presence of higher proportion of amylose,the mixed gel showed higher consistency coefficient K and lag ring area,and lower fluid index n.The textural properties of the mixed gel were influenced by the proportion of amylose.Hardness,adhesiveness and cohesiveness of the gel significantly increased with the increase of the proportion of amylose.It is concluded that the amylose proportion of the starch in the pectin gel was a great determinant of gel property.Hydrogen bonding between pectin and starch might was a major physical force affecting gel texture as testified by adding urea.