海藻糖对大米淀粉回生特性的影响

Effect of Trehalose on Retrogradation Properties of Rice Starch

为探究海藻糖对大米淀粉回生特性的影响,使用原子力显微镜、低场核磁共振、傅里叶变换红外光谱、差示扫描量热分析等方法,对淀粉分子结构、水分分布以及流变学和热力学特性进行了研究。结果表明:4℃回生3 h和24 h后,添加质量分数1.6%海藻糖的大米淀粉(T-淀粉)浸出的直链淀粉比大米淀粉分别降低了8.6%和11.5%。淀粉回生过程中分子链构象收缩,向有序规则化趋势排列,而添加海藻糖可以抑制分子构象的收缩。大米淀粉回生24 h后有序程度增加了19.0%,而T-淀粉回生24 h后有序程度仅比未回生淀粉增加了3.0%,海藻糖能显著降低大米淀粉体系的短程有序结构。T-淀粉与水分子的结合能力(强、弱结合水)显著高于大米淀粉(P<0.05)。T-淀粉体系中自由水的析出以及重结晶进程受阻,是抑制淀粉短期回生的原因之一。加入海藻糖后淀粉体系的回生焓和回生度均显著降低,且海藻糖带来的这种优势随着老化时间的延长越发凸显,T-淀粉体系长期回生的回生焓显著降低。因此,海藻糖不仅可以有效抑制淀粉的短期回生,对长期回生也有较好的抑制作用。

In order to investigate the effect of trehalose on the retrogradation properties of rice starch,the molecular structure,water distribution,rheological and thermodynamic properties were studied by means of atomic force microscope,low-field nuclear magnetic resonance,Fourier transform infrared spectroscopy and differential scanning calorimetry analysis.The results showed that the leached straight chain amylose contents of rice starch with the addition of 1.6% trehalose(T-starch),which were stored at 4℃ for 3 h and 24 h were decreased by 8.6% and 11.5% compared with rice starch,respectively.The arrangement of the starch molecular chains trended to aggregate to an ordered structure with the retrogradation.However,the addition of trehalose could inhibit the aggregation.The order degree of rice starch increased by 19.0%,but the order degree of T-starch only increased by 3.0% after retrogradation for 24 h,indicating that the trehalose could significantly decrease the proportion of short-term order structure of rice starch.The binding ability of T-starch to water molecules(strongly and weakly bound water)was significantly higher than that of rice starch(P<0.05).The free water precipitation and recrystallization in T-starch system were blocked,which was one of the reasons for inhibiting the short-term retrogradation of starch.After the addition of trehalose,both regenerative enthalpy and retrogradation degree of the long-term retrogradation of T-starch were significantly reduced.And this advantage brought by trehalose became more and more prominent with the extension of aging time,and the long-term retrogradation enthalpy of T-starch system was significantly reduced.Therefore,trehalose could not only effectively inhibit the short-term retrogradation of starch,but also had a good inhibitory effect on long-term retrogradation.