黄原胶对大米淀粉长期回生的影响

Effect of Xanthan on Long-Term Retrogradation of Rice Starch

研究了黄原胶(Xan)对大米淀粉(RS)长期回生的影响,黄原胶和大米淀粉可以形成质地更为柔软的凝胶,黏着性升高,内聚性下降。X-射线衍射结果表明黄原胶能降低淀粉的重结晶度,用Avrami方程拟合结晶动力学,大米淀粉/黄原胶体系支链淀粉的重结晶生长为一次成核(n<1),添加黄原胶后,结晶速率常数k降低,表明大米淀粉的成核速度和重结晶增长速度都降低,支链淀粉回生受到较大抑制。扫描电镜(SEM)显示黄原胶能填充于淀粉颗粒片段间,体系表面孔洞缩小,表面更加光滑,形成的结构更加致密。

In this study, the long-term retrogradation of the rice starch （RS）/xanthan （Xan） mixtures was investigated. The mixtures could form softer gel with higher adhesiveness and lower cohesiveness. After 14 days＇ storage,recrystallization of the RS/Xan mixtures decreased,comparing with the native RS. The growth of amylopectin recrystallization in RS/Xan mixtures was primary nucleation （n〈1）. However,the rate of recrystallization and nucleation reduced which indicated that the long-term retrogradation was evidently inhibited. It showed that Xan filled in the fragments of the starch granules leading to smaller surface pores,smoother surface and more compact structure by scanning electron microscopy （SEM）.