羟丙基葛根淀粉的制备及性能研究

Study on Preparation and Property of Hydroxypropyl Pueraria Starch

以葛根淀粉为原料,环氧丙烷为醚化剂,氢氧化钠为催化剂,无水硫酸钠为膨胀抑制剂,对羟丙基葛根淀粉的制备和性能进行了研究。考察了反应温度、反应时间、氢氧化钠用量、环氧丙烷用量以及无水硫酸钠用量对羟丙基葛根淀粉取代度的影响。采用分光光度法测定羟丙基葛根淀粉的取代度,用热重分析仪(TGA)、差示扫描量热仪(DSC)对其热特性进行了测试。制备羟丙基葛根淀粉的较佳工艺为:反应温度45℃,反应时间18 h,氢氧化钠用量1.2%,环氧丙烷用量10%,无水硫酸钠用量12%(氢氧化钠用量、环氧丙烷用量、无水硫酸钙用量均为占干淀粉质量分数)。葛根淀粉经羟丙基化后,透明度、冻融稳定性、抗酸碱性、膨胀能力增强,凝沉性减弱,且其分解温度及糊化温度均下降,扩大了其应用范围。

The preparation and property of hydroxypropyl pueraria starch were studied by using pueraria starch as raw materials, epoxypropane as etherization reagent, sodium hydroxide as catalyst, sodium sulfate as gelatinization inhibitor. The effect of reaction temperature, reaction time, sodium hydroxide dosage, epoxypropane dosage and sodium sulfate dosage on the substitution degree of the hydroxypropyl pueraria starch has been investigated. The spectropho- tometer method was used to assay the substitution degree of hydroxypropyl pueraria starch by differential scanning cal- orimetry （DSC） and thermogravimetric analyzer （TGA）, the thermal property of hydroxypropyl pueraria starch was measured. The better technology conditions of preparing hydroxypropyl pueraria starch are reaction temperature 45 ~C, reaction time 18 h ,amount of sodium hydroxide 1.2% ,amount of epoxy propane 10% , and amount of anhydrous sodi- um sulfate 12% respectively （the amount of epoxy propane, anhydrous sodium sulfate and sodium hydroxide are the mass percentage of dry starch）. The transparency,freeze- thaw stability,acid resistance,alkali resistance and expan- sion ability of the product increase, hut the retrogradation, decomposition temperature and gelatinization temperature decrease in the modification of pueraria starch and enlarge application fields.