低分子质量淀粉的制备及其结构研究

摘要

The hydrochloric acid hydrolysis method was employed to prepare the low molecular weight (LMW) of starch, and the starch production with different molecular weight (MW) was achieved by controlling the reaction time.The he MW of starch decreases gradually with the increase of reaction time.The relationship between the MW of starch (Mv) and reaction time (t) can be fitted by a power function, expressed as Mv=4.43×105×t-1.41.The LMW of starch has been characterized by Fourier transform infrared spectroscopy (FTIR), thermal gravity analysis (TGA) and X-ray diffraction (XRD).The results indicate that as the decrease of the MW, the number of characteristic groups grafted in the starch chain progressively increases, as well as the thermal stability decreases inch by inch.After the hydrolysis of the starch, the crystal structure changes with the decrease of degree of crystallinity.As the decrease of the starch's MW, the crystallinity gradually decreases from 38.5% and the crystal structure finally disappears, and changes to the amorphous structure.The results provide references for research on the structural properties of LMW of starch.%采用盐酸酸解法制备低分子质量淀粉,通过控制淀粉水解反应时间制备不同分子质量的淀粉产物.淀粉分子质量(Mv)随酸水解时间的延长不断降低,且与水解反应时间(t)呈乘幂关系,即Mv=4.43×105×t-1.41.傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FTIR)、热重分析(thermal gravity analysis,TGA)和X射线衍射(X-Ray Diffraction,XRD)的研究结果表明,随着淀粉分子质量的降低,淀粉特征基团的数目逐渐增加,热稳定性逐渐降低.淀粉酸解后,其结晶结构发生变化,结晶度下降,且随着淀粉分子质量的降低,其结晶度由原淀粉的38.5%逐渐下降,直至结晶结构消失,变为无定形结构.所得结果为低分子质量淀粉结构性质的研究提供了一定的参考.