不同结晶度几丁质纳米晶体制备皮克林乳液稳定性研究

通过酸解的方法获得不同结晶度的几丁质纳米晶体(Ch N),采用均质协同超声技术制备O/W型皮克林乳液。通过X射线衍射和傅里叶红外光谱计算分析了几丁质纳米颗粒的结晶度及官能团变化,进而对O/W乳液的微观结构、界面接触角、物理稳定性、热稳定性、乳析稳定性、储藏稳定性进行测定,分析了不同结晶度的Ch N对乳液稳定性的影响。结果表明:酸解并不会破坏几丁质的官能团,但是酸解可以改变几丁质的结晶度,且酸解2. 5 h时获得的Ch N结晶度最大,为78. 15%;结晶度高的Ch N制备的乳液形成更稳定的网状结构,Ch N更多地附着在油-水界面,使得乳液具有更小的界面接触角,提高了乳液的亲水性;研究还发现,结晶度高的Ch N制备的乳液热稳定性指数和物理稳定性指数较高,分别为63%和69. 52%;乳析稳定性好,乳析指数不足1%;另外,Ch N稳定的乳液在常温下储藏30 d均不分层,具有良好的储藏稳定性,且结晶度最高的Ch N制备的乳液粒径最小,储藏稳定性最好。因此,可以通过提高几丁质纳米晶体的结晶度制备稳定的O/W型皮克林乳液。

Stability of Pickering Emulsions Prepared by Different Crystallinity Index Values Chitin Nanocrystals

Chitin nanocrystals (ChN) with different crystallinity index values were obtained by acid hydrolysis method, and O/W type Pickering emulsion was prepared by homogeneous synergistic ultrasonic technology. The crystallinity index values and functional groups of chitin nanoparticles were calculated and analyzed by X-ray diffraction and Fourier infrared spectroscopy. The microstructure, interfacial contact angle, thermal stability, physical stability, creaming stability and storage stability of the emulsion were determined. The effect of different crystallinity index values of ChN on emulsion stability was analyzed. Result showed that acid hydrolysis did not destroy the chitin functional group, but acid hydrolysis can change the crystallinity index values of chitin, and the crystallinity index values of ChN obtained at the acid hydrolysis of 2.5h was the largest, which was 78.15%;the emulsion prepared by ChN with high crystallinity index values formed a more stable network structure, and ChN was more attached to the oil-water interface, so that the emulsion had a smaller interface contact angle and increased the hydrophilicity of the emulsion;it was also found that the ChN stable emulsion with high crystallinity index values had good thermal stability index and physical stability index, which were 63% and 69.52%, respectively;the emulsion analysis stability was good, and the emulsification index was less than 1%. In addition, the ChN-stabilized emulsion did not stratify after storage for 30 days at room temperature, and had good storage stability, and the emulsion with the highest crystallinity index values had the smallest particle size. Therefore, a stable O/W Pickering emulsion can be prepared by increasing the crystallinity index values of the chitin nanocrystals.