丁酸酐改性多孔淀粉作为Pickering乳液稳定剂的应用研究

Application of butyric anhydride modified porous starch as Pickering emulsion stabilizer

为合成较高取代度的丁酸酐改性淀粉,探究其乳化性和乳化稳定性,该研究以酶改性多孔淀粉(porous starch,PS)为主体,丁酸酐(butyric acid,BA)为客体,在碱性水相体系中制备了取代度为0.023~0.148的丁酸酐改性多孔淀粉(butyric anhydride porous starch ester,BA-PS),并以其作为稳定剂制备Pickering乳液。扫描电子显微镜和N_(2)-吸附/脱附结果表明,PS表面分布着较为均匀的孔洞结构,平均孔径为11.13 nm,颗粒比表面积为3.9144 m^(2)/g,酯化改性后BA-PS仍保留PS原有的颗粒形态;傅立叶红外光谱和核磁共振氢谱谱图的结果相互印证了BA对PS酯化改性的成功;X射线衍射结果表明,PS和BA-PS都保留了天然淀粉原有的结晶形态;制备的Pickering乳液贮存20 d后观察结果表明,天然淀粉(native starch,NS)不具有乳化性,酶改性赋予PS一定的乳化性能,但其乳化能力仍然有限,而BA-PS的乳化性要远优于NS和PS,且改性程度越高,制备的乳液液滴均匀性越好,尺寸越小,乳化能力越强。该研究表明,丁酸酐改性淀粉具备较好的乳化性和乳化稳定性,对以其为稳定剂制备的Pickering乳液,可进一步进行药物或活性物质的递送研究。

In order to synthesize butyric anhydride modified starch with higher degree of substitution(DS)and explore its emulsification performance and emulsification stability,butyric anhydride modified porous starch(PS)with DS of 0.023-0.148 was prepared in alkaline aqueous system with enzyme modified PS as the main body and butyric acid(BA)as the guest(butyric anhydride porous starch ester,BA-PS).Then,itwas used as stabilizer to prepare Pickering emulsion.Scanning electron microscope(SEM)and N 2-adsorption/desorption results showed that the PS surface was distributed with a relatively uniform hole structure.The average pore diameter was 11.13 nm and the BET was 3.9144 m^(2)/g.The esterified BA-PS still retains the original particle shape of PS.Moreover,Fourier transform infrared spectroscopy(FT-IR)and 1HNMR spectrum mutually confirmed the success of BA's esterification modification of PS.X-ray diffraction(XRD)showed that both PS and BA-PS retained the original crystalline form of natural starch;The Pickering emulsion results showed that after 20 days storage native starch(NS)had no emulsifying properties,and the PS obtained by enzyme modification had certain emulsifying properties.However,the emulsifying ability was limited.Meanwhile,BA-PS obtained by butyric anhydride modification the emulsification performance was much better than that of NS and PS,and with the degree of substitution increased,the emulsification ability gradually increased.The better the uniformity of the droplets of the prepared emulsion,the smaller the droplet size.This study showed that butyric acid-modified starch had better emulsification and emulsification stability.Pickering emulsion prepared with it as an emulsifier can be used for further drug or active substance delivery research.