正交试验优化交联乙酰化葛根淀粉工艺条件及性能

Optimization of Preparation Conditions for Cross-Linked Acetylated Kudzu Starch by Orthogonal Array Design and Its Properties

为改善葛根淀粉性能,拓宽应用领域,对葛根淀粉进行交联乙酰化复合改性。采用湿法研究醋酸酐用量、反应温度、反应时间、pH值对交联乙酰化葛根淀粉取代度的影响,从而优化其工艺参数。用红外光谱仪、热重分析仪(TGA)、差示扫描量热仪(DSC)分别对交联乙酰化葛根淀粉的结构与热特性进行了表征与测试。结果表明,制备交联醋酸酯葛根淀粉的最佳工艺条件为:反应温度30℃、反应时间60min、pH8.5。葛根淀粉经交联、乙酰化后,其冻融稳定性、热黏度稳定性、抗酸性、抗碱性增强。葛根淀粉经乙酰化后,其膨胀能力增加,而葛根淀粉经交联后,其膨胀能力降低。与葛根淀粉相比,交联乙酰化葛根淀粉的DSC曲线吸收峰的起始温度、峰值温度、结束温度、焓变降低,但热稳定性增加。

Kudzu starch was acetylated and cross-linked to improve its properties and thus broaden its applications. The effect of amount of acetic anhydride, reaction temperature, reaction time and pH on the substitution degree of cross-linked acetylated kudzu starch （CLAKS） was investigated by the wet method to establish the optimum conditions for forming CLAKS. The structure and thermal properties of CLAKS were characterized by infrared spectroscopy （IR）, differential scanning calorimeter （DSC） and thermogravimetric analyzer （TGA）. The results indicated that the optimum conditions for preparing the modified starch were reaction temperature 30 ℃, reaction time 60 min and pH 8.5. After acetylation and cross- linking, kudzu starch showed improvements in freeze/thaw stability, thermal viscosity stability, acid resistance and alkali resistance. Its swelling powder was increased by acetylation but reduced by cross-linking. DSC analysis showed that the peak onset temperature, peak temperature, peak end temperature and enthalpy change of the modified starch reduced, but its thermal stability increased compared with those of the native starch.