微波处理对莲子淀粉理化性质的影响

Effect of Physical and Chemical Properties of Lotus Seed Starch by Microwave Treatment

摘要:

为探讨微波处理对莲子淀粉的改性作用，本文利用微波工作站对莲子淀粉进行加热处理，观察预处理后的淀粉颗粒形态变化、后期糊化过程中直链淀粉溶出量和流变特性，结果表明，30%的莲子淀粉乳经不同微波功率处理后，其颗粒形态未发生明显变化，仍呈现光滑的椭球状；随着微波功率的增强，颗粒间出现了明显的聚集粘结行为，颗粒的平均粒径最大值可达26.37 μm，为原淀粉2.15倍，同时淀粉颗粒晶区比例增大，995/1024吸收峰比值由0.89上升至0.99；经微波处理后的莲子淀粉，其淀粉糊的直链淀粉溶出量由120 mg/g下降至87.89 mg/g，淀粉糊触变性、流变粘度及弹性模量也均有降低。这说明微波处理可促使莲子淀粉拥有更紧密的晶区结构，并在后期的糊化过程中，对淀粉颗粒膨胀可能起到了一定的抑制作用，造成直链淀粉溶出量减少，从而导致淀粉糊流变特性发生变化。

Abstract:

In this study, physical and chemical properties of lotus seed starch by microwave treatment was investigated. Lotus seed starch paste (30%) was heated in a microwave station and changes in starch particle shape, the amount of dissolution, and rheological properties of amylose during gelatinization were observed. The result showed that after treatment with different microwave intensities, no apparent change in the shape of starch particles was observed, where the granules remained smooth and oval. However, apparent aggregation of starch particles was observed with the increase in microwave intensity, with maximum average particle diameter at 26.37 μm, which was 2.15 times that of untreated starch. Additionally, the proportion of crystalline starch particles increased and the 995/1024 absorption peak ratio increased as well, from 0.89 to 0.99. Lotus seed starch treated by microwaves showed a decrease in amylose dissolution from 120 to 87.89 mg/g. Moreover, the thixotropic, rheology viscosity, and elasticity modulus of the starch paste also decreased. These indicate that microwave treatment could encourage tighter crystalline regions in the lotus seed starch and shows certain inhibition of swelling of the starch particles during subsequent gelatinization. This leads to a reduction in the amount of dissolution of amylose and changes in the rheological properties of starch.