不同胶体对玉米淀粉糊化及流变学特性的影响

Effects of Different Colloids on Gelatinization and Rheological Properties of Corn Starch

通过对玉米淀粉中添加不同的胶体(果胶P、黄原胶XG、瓜尔豆胶GG、魔芋胶KGM、阿拉伯树胶AG、羟丙基甲基纤维素HPMC),并测定其黏度、热力学及流变学特性的变化,探索不同胶体对玉米淀粉糊化及流变学特性的影响。结果表明:不同胶体与玉米淀粉的混合体系容易产生各种反应与相互作用,从而表现出不同的糊化及流变学特性。添加阿拉伯树胶后的混合胶体黏度变化速度降低,而添加其余胶体后混合体系的黏度均升高,添加黄原胶后混合胶体的起始黏度升高,而添加了其他的胶体后变化不大。在25~180℃,DSC结果表明:添加了果胶和黄原胶后的混合胶体起始温度升高,而其他的胶体均下降,且全部的终止温度都有提高。添加了不同胶体与原淀粉的混合体系均随剪切频率增大而出现剪切稀化现象,所以可以确定体系为假塑性流体。添加了果胶、黄原胶的胶体表观黏度小于原淀粉,而添加其他胶体(瓜尔豆胶、魔芋胶、阿拉伯树胶、羟丙基甲基纤维素)的混合体系均有不同程度地升高。玉米淀粉与添加胶体的混合体系的结构发生了一些变化,导致混合体系的特性也发生变化,结果显示添加了胶体(P和AG)后混合体系的硬度比原淀粉升高,添加其他的胶体均减小;添加了胶体(P和KMG)后混合体系的黏性比原淀粉升高,添加其他的胶体均减小。

Six different colloids pectin(P),xanthgum(XG),Guarana Gum(GG),konjac gum(KGM),Arabic gum(AG),hydroxypropyl methylcellulose(HPMC)were added into the corn starch respectively.Their gelatinization,viscosity,thermodynamics and rheological characteristics were explored.The results showed that different colloids and corn starch mixture systems were prone to various reactions and interactions,thus showing different gelatinization and rheological properties.The viscosity of the mixed colloids decreased after the addition of AG,while the viscosity of the other five the mixed system after the addition of the remaining colloids increased,and the starting viscosity of the mixed colloids increased after the addition of yellow raw gum XG,whereas the addition of other colloids changed little.The results of DSC from 25 to 180℃showed that the starting temperature of mixed colloids with P and XG increased,while other colloids decreased and all termination temperatures increased.The mixed systems with different colloids and prostarch appear with increasing shear frequency,so the system could be determined as pseudoplastic fluid.The apparent viscosity of colloids with P and XG was less than that of primary starch,while the mixed system with other colloids(GG,KGM,AG,HPMC)increased to varying degrees.The structure of corn starch and colloid changes,causing the characteristics of the mixed system,such as the colloid(P,AG),the colloid(P,KMG)and the other colloids and the application of the colloids in the production and processing of corn starch food.