蔗糖和海藻糖对糯米淀粉凝胶冻融稳定性的影响

为提高糯米淀粉凝胶冻融稳定性,研究了蔗糖和海藻糖对淀粉凝胶析水率、质构特性、热特性及微观结构的影响。结果表明,经过5次冻融处理,蔗糖和海藻糖均能显著降低淀粉凝胶析水率,且添加6%蔗糖与添加4%海藻糖对凝胶析水率的影响相同。添加2种糖后,凝胶弹性增加,硬度先增大后减小。差示扫描量热仪测定显示添加2种糖的淀粉凝胶熔融焓/糊化焓均显著降低,表明淀粉老化受抑制,且抑制能力为海藻糖大于蔗糖。利用扫描电镜观察凝胶微观结构发现,添加海藻糖的淀粉凝胶表面光滑平整,凹洞较小,基质较紧密。与蔗糖相比,海藻糖更能提高糯米淀粉凝胶冻融稳定性。

Effect of Sucrose and Trehalose on Freeze-thaw Stability of Waxy Rice Starch Gel

To improve the freeze-thaw stability of waxy rice starch gel, the effect of sucrose and trehalose on syneresis, texture properties, thermal properties and microstructure of waxy rice starch was investigated. The results showed that sucrose and trehalose reduced effectively the syneresis of the waxy rice starch gel after 5 freeze-thaw cycles. The syneresis of waxy rice starch gel was consistent with 6% sucrose and 4% trehalose.The sucrose and trehalose increased the springiness and hardness of waxy rice starch gel with addition. Differential scanning calorimetry showed that sucrose and trehalose reduced the retrogradation enthalpy significantly, the aging of starch was inhibited and the inhibition capacity of trehalose was greater than that of sucrose. Scanning electron microscope image showed that the surface of starch gel was smooth, the pores was smaller and the matrix surrounding the pores was stronger with trehalose. Trehalose improved the freeze-thaw stability of waxy rice starch gel more than sucrose. Compared with sucrose, trehalose can improve the freeze-thaw stability of waxy rice starch.