亲水胶体对米糠混合物凝胶及热行为的影响

目的 研究海藻酸钠、果胶、菊粉和魔芋胶等4种亲水胶体对米糠-小麦粉混合体系凝胶化过程及体系水分蒸发造成的水合稳定性影响,以改善因添加米糠而造成米糠-小麦混粉面食品质稳定的问题.方法 将4种亲水胶体以一定配比与米糠-小麦粉形成混合体系,动态粘弹性曲线能反映弹性模量、黏性模量和损耗因子的变化,分析混合体系凝胶化的过程,同时从混合体系的热重曲线(TG)和质量损失随时间变化的一阶导数曲线(DTG)中分析体系质量损失随温度的变化情况.结果 海藻酸钠、果胶、菊粉和魔芋胶各亲水胶体的加入与淀粉体系形成了更多的三维网络结构,4种亲水胶体-米糠-小麦共混体系中的弹性模量均大于黏性模量,4种亲水胶体的加入均不同程度减弱了混合体系加热过程中水分的迁移速率.结论 亲水胶体可提前米糠-小麦粉混合物的凝胶点时间,对米糠-小麦粉共混体系中水分蒸发迁移的改善能力由强到弱的顺序为海藻酸钠＞果胶＞魔芋胶＞菊粉.

Effect of Hydrophilic Colloid on Gel and Thermal Behavior of Rice Bran Mixture

The effect of hydrophilic colloids, such as sodium alginate, pectin, inulin and konjac gum, on the both gelatinization and hydration stability of rice bran-wheat flour blending system was investigated to improve the quality of bran-wheat flour food. The 4 hydrocolloids were mixed with rice bran-wheat flour in a certain ratio. This experiment was carried out to investigate gelling process through changes of both elastic modulus viscous modulus and loss factor. Meanwhile, water evaporation during gelatinization was analyzed by means of both TG and DTG thermogravimetric curves of blending system. The results showed that the gelation process was changed and the gel points of blending system with the hydrophilic colloids were almost appeared earlier than that of system without hydrophilic colloids, and the addition of four hydrophilic colloids weakened the water migration rate in the heating process of the mixed system to varying degrees. In addition, the order of improvement effect from strong to weak was sodium alginate > pectin > konjac gum > inulin with the same addition amount.