本文采用蜡质玉米、普通玉米和高直链玉米淀粉为原料，改变有效氯添加量，制备羟丙基氧化淀粉，通过XRD、DSC、Brabender粘度仪等测定手段，研究不同直链淀粉含量对羟丙基氧化淀粉理化性质的影响。实验表明，直链淀粉含量对羟丙基化和氧化程度影响显著，其中直链淀粉含量高有利于羟丙基化，而不利于氧化；X-射线衍射分析发现，改性淀粉没有改变晶型，随氧化程度增加，淀粉分子结晶度下降，直链淀粉含量越高，下降趋势越缓；DSC测试和Brabender粘度分析表明，直链淀粉含量直接影响到羟丙基氧化淀粉糊化特性，糊化温度：高直链>普通>蜡质，糊粘度：蜡质>普通>高直链，糊化焓：蜡质>普通>高直链；通过观察淀粉的偏光特性和颗粒表面形态，发现直链淀粉含量越高，羟丙基氧化淀粉的偏光十字越弱，颗粒越不易破碎。

Waxy corn (WC), common corn (CC), and high-amylose cornstarches (AMC) were used as the raw materials in this study, and different amounts of chlorine were used to prepare hydroxypropyl-oxidized starches. The effect of amylose content on the physicochemical properties of hydroxypropyl-oxidized starches was investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Brabender viscosity analysis. The results indicated that high amylose content favored hydroxypropylation, but was not conducive to oxidation. The XRD observations showed that the crystal type was not changed in the modified starches. With increasing degrees of oxidation, the crystallinity of starch molecules decreased, and the decreasing tendency slowed down with increasing amylose content. DSC and Brabender viscosity analysis indicated that amylose content directly affected the gelatinization and paste properties of hydroxypropyl-oxidized starches. The gelatinization temperatures, viscosities, and gelatinization enthalpies of the three starches were in the following orders: gelatinization temperature: AMC > CC > WC, viscosity: WC > CC > AMC, and gelatinization enthalpy: WC > CC > AMC. Observation of the starch properties under polarized light and the surface morphology of starch granules showed that a high amylose content led to a weak polarization intensity for hydroxypropyl-oxidized starches, and starch granules that were not easily cracked.

广东省部产学研项目（2012B091100291）；东莞市产学研合作项目（2014509111106）