极限糊精对小麦淀粉回生的影响

Influence of Limit Dextrin on Wheat Starch Retrogradation

摘要:

为进一步阐述α淀粉酶抑制淀粉回生的机理, 作者采用广角X射线衍射法(WXRD)和差示扫描量热法(DSC)表征极限糊精对小麦淀粉回生的影响。WXRD结果显示, 小麦淀粉中加入10%的F75和F88极限糊精组分, 回生样品的相对结晶度分别为3.09%和2.74%, 均小于不加极限糊精的相对结晶度(3.28%)。DSC结果也表明, 极限糊精组分F75和F88均可降低小麦淀粉的回生焓值。用Avrami方程拟合小麦淀粉结晶动力学, 小麦淀粉的重结晶生长为一次成核(n<1), 添加极限糊精后, 结晶速率常数k降低, 表明小麦淀粉的成核速度降低, 淀粉回生受到抑制。此外, 还采用分子动力学模拟的方法预测极限糊精影响淀粉片段回生过程。结果表明, 极限糊精与淀粉片段间经非共价作用阻碍淀粉链靠近形成有序化结构。

Abstract:

The effect of limit dextrin on wheat starch retrogradation was investigated to explain the anti-firming mechanism of α-amylase. The degree of crystallinity of retrogradation wheat starch were reduced with the addition of F75 limit dextrin and F88 limit dextrin, respectively. DSC results also showed that the enthalpy change of retrogradation wheat starch were reduced with the addition of limit dextrins(F75 or F88). The growth of amylopectin recrystallization in wheat starch/limit dextrin mixtures was primary nucleation(n<1). Furthermore, the rate of recrystallization(k) reduced which indicated that the wheat starch retrogradation was inhibited. In addition, molecular dynamic simulation was adapted to predict the interaction of limit dextrin and starch fraction, and the results showed that the limit dextrin reduced starch retrogradation by the interplay between limit dextrin and starch fraction.