基于非对称场流分离技术研究直链/支链比值对小米淀粉退化行为的影响

退化是淀粉糊化后分子链重排的过程,为了探究直链/支链比值对淀粉退化的影响,本文采用碱性甘油超声提取小米淀粉中直链淀粉,通过非对称场流分离技术、差示扫描量热法、傅里叶变换红外光谱、扫描电子显微镜、X线衍射法,对3种不同直链/支链比值的小米淀粉的颗粒形貌、晶体结构、结晶度、糊化特性、退化行为进行了表征.实验结果表明,碱性甘油超声提取法对小米淀粉颗粒形态影响较小,晶体结构未发生改变,对糊化温度无显著影响;3种小米淀粉中直链淀粉的含量为蜡质小米淀粉<碱性甘油超声提取小米淀粉<普通小米淀粉.实验结果证明在4 ℃储存7 d小米淀粉的退化程度与直链淀粉含量呈正相关.

Effect of the amylose/amylopectin ratio on the millet starch retrogradation by asymmetrical flow field-flow fractionation

Retrogradation is the process of rearrangement of molecular chains after starch gelatinization. In order to explore effect of the amylose/amylopectin ratio on the millet starch retrogradation, alkaline glycerin was used to extract amylose from millet starch.Asymmetrical flow field-flow fractionation(AF4), differential scanning calorimetry. Fourier transform infrared spectroscopy, scanning electron microscopy,and X-ray diffraction were employed to characterize the morphology, crystal structure, crystallinity, gelatinization and retrogradation of millet starch with three different amylose/amylopectin ratios.It was found that alkaline glycerin treatment had slight effect on the morphology, crystal structure, and gelatinization temperature of millet starch.The content of amylose in three millet starch samples was in the following order: waxy millet starch