以玉米醇溶蛋白(zein)和阿拉伯胶(arabic gum,AG)为原料,通过反溶剂法制备纳米颗粒,形成核壳结构的zein-AG运载体系。通过研究zein储备液质量浓度、体系中乙醇与水体积比(醇水比)、pH值、盐离子浓度对纳米颗粒稳定性影响,制备高效负载生育酚的zein-AG纳米颗粒。实验结果表明,zein储备液质量浓度为50 g/L,醇水比为1∶50,zein与AG的质量比为1∶1.5时,形成粒径为122.6 nm,多分散指数(PDI)为0.17,电位为-32.8 mV的稳定纳米颗粒;在pH=3~9内zein-AG纳米颗粒粒径在120~140 nm;pH=3时zein-AG纳米颗粒电位较低为-17.8 mV,但pH=4~9时电位在-25~-40 mV,PDI在0.3以下,非常稳定;盐离子浓度不超过20 mmol/L时,纳米颗粒粒径均为纳米级,超过20 mmol/L时纳米颗粒发生严重絮凝,证明zein和AG为静电相互作用力结合,有一定的电荷屏蔽作用。当纳米颗粒与生育酚质量比为1∶5时,包封率达到86.9%以上,且粒径、PDI、电位均在稳定范围内。复合AG的zein纳米颗粒的稳定性、耐盐耐酸碱性、对生育酚负载率均有显著提高。
The zein-arabic gum (AG) delivery system was prepared by zein and AG through anti-solvent method. The effects of the concentration of zein, the ratio of the ethanol to water, pH and the concentration of salt on the stability of nanoparticles were studied. High content tocopherol (TOC)- AG nanoparticle was also prepared. The results showed that 5% of zein, 1∶50 ratio of ethanol: water and zein∶AG =1∶1.5 was the best condition to prepare 122.6 nm zein-AG nanoparticles, with the polydispersity index (PDI) of 0.17 and zeta electric potential of -32.8 mV. The particle size of zein-AG nanoparticles was in the range of 120-140 nm at pH 3-9. The zeta electric potential was -17.8 mV at pH=3 and -25-40 mV at pH 4-9, the PDI were all below 0.3. These data showed the zein-AG nanoparticles were very stable. When the concentration of salt is less than 20 mmol/L, the particles are nanoscale. The particles flocculated at salt concentration more than 20 mmol/L proved that AG and zein nanoparticles combination was due to the electrostatic attraction. When the ratio of zein-AG nanoparticles to TOC is 1∶5, the encapsulation efficiency was more than 86.9%, and the particle size, PDI, zeta-potential of the nanoparticles were all stable. The stability of compound nanoparticle of AG and zein, as well as the tolerance of acid, alkali and salt all improved the encapsulation efficiency of TOC.