采用直链淀粉含量不同的玉米淀粉为原料，在环氧丙烷与次氯酸钠用量一定的条件下，进行氧化和羟丙基化复合变性，研究变性顺序对淀粉理化性质的影响． 之后分析
了改性玉米淀粉的透明度和Brabender 黏度，并用X 射线衍射法进行了表征． 实验结果表明: 氧化－ 羟丙基淀粉羰基和羧基的摩尔取代度更高，羟丙基－ 氧化淀粉的羟丙基摩尔取代度更高; 氧化－ 羟丙基淀粉比羟丙基－ 氧化淀粉的透明度更高; 羟丙基－ 氧化淀粉的峰值黏度高于氧化－ 羟丙基淀粉; 两种变性方法均未改变淀粉分子的晶型; 复合改性与改性顺序密切相关，先反应的起主导作用; 支链淀粉含量高有利于氧化改性，直链淀粉含量高有利于羟丙基醚化改性．

By taking the corn starches of different amylose contents as raw materials and by fixing the dosage of propylene oxide and sodium hypochlorite,an oxidation and etherification dual-modification was carried out so as to reveal the effects of the modification sequence on the physicochemical properties of the corn starches.Then,the modified corn starches were analyzed in terms of transparency and Brabender viscosity,and they were characterized by means of XRD.Experimental results show that ( 1) the carbonyl and carboxyl of the oxidized-hydroxypropylated starches have higher molar substitution degrees,while the hydroxypropyl of the hydroxypropylated-oxidized starches has a higher one; ( 2 ) the transparency of the oxidized-hydroxypropylated starches is higher than that of the hydroxypropylated-oxidized starches; ( 3) the peak viscosity of the hydroxypropylated-oxidized starches is higher than that of the oxidized-hydroxypropylated starches; ( 4) both the two kinds of modification do not change the crystal form of starch molecules; ( 5) the dual-modification is closely related to the modification order,and the first reaction plays a leading role; and ( 6) lower amylose content is beneficial to the oxidative modification,while higher amylose content is beneficial to the hydroxypropyl modification.