Effects of hydrocolloids on corn starch retrogradation
In this work, three kinds of hydrocolloids were used to investigate the effect of short-term and long-term retrogradation of corn starch to understand the mechanism of the hydrocolloid action on starch granules. Various analytical techniques, including the rapid viscosity analyzer, rheometer, differential scanning calorimetry (DSC), and dispersion stability analyzer, were used to determine the gelatinization and phase separation behavior and to understand the effect of hydrocolloids on the mechanism of starch retrogradation. DSC revealed that short-term retrogradation of amylose was retarded and restricted by xanthan gum. The X-ray diffraction indicated that the xanthan gum could prevent the recrystallization of amylopectin. The stability analysis, which was performed with the Turbiscan Easy Soft software, clearly suggested that addition of xanthan and guar gum can strongly stabilize the corn starch; this was quantified using the Turbiscan stability index. Thus, our results showed that xanthan and guar gum can improve the stability of corn starch/hydrocolloid systems.