聚葡萄糖对大米淀粉凝胶老化特性的影响

为探究聚葡萄糖(PD)对大米淀粉(RS)凝胶老化特性的影响,利用快速黏度分析仪(RVA)、差示扫描量热分析(DSC)、X-射线衍射分析(XRD)和扫描电子显微镜(SEM)研究聚葡萄糖对大米淀粉糊化黏度特性、热特性、晶体结构和微观结构的影响。结果表明,随着聚葡萄糖添加量的增大,大米淀粉糊化的峰值黏度、崩解值和回生值均显著下降(p<0.05);但是糊化温度升高,大米淀粉的糊化焓值和老化焓值均显著降低(p<0.05),大米淀粉凝胶的相对结晶度从14.09%降到8.61%。SEM结果表明添加聚葡萄糖后,大米淀粉凝胶孔洞变小,表面更致密、光滑,说明聚葡萄糖可以抑制大米淀粉凝胶的重结晶,延缓大米淀粉凝胶的老化。

Effect of polydextrose on the retrogradation of rice starch gel

To investigate the effect of polydextrose (PD) on the retrogradation of rice starch (RS) gel, rapid viscosity analyzer (RVA), different scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to investigate the change of viscosity, thermodynamic properties, crystal and micro structure of rice starch gel. RVA results showed that addition of polydextrose lowered the peak viscosity, final viscosity, breakdown and setback values, but increased the gelatinization temperature of rice starch. DSC results showed the gelatinization and retrogradation enthalpy significantly decreased with the increasing polydextrose concentrations. Moreover, the relative crystallinity also decreased from 14.09% to 8.61%. The microscope structures images showed polydextrose made the pore of rice starch gel smaller, and the surface more intensive and smoother. These results suggested that the addition of polydextrose could restrain the recrystallization of rice starch gel and inhibit the retrogradation of rice starch gel.