酪蛋白-海藻酸钠基乳液凝胶性质及其在姜黄素负载中的应用

Properties of Emulsion Gels Based on Casein-Sodium Alginate and Their Application on Curcumin Delivery

姜黄素(curcumin,Cur)是一种天然活性物质,具有抗氧化、抗炎、降血脂等多种生物活性;但存在稳定性差、口服生物利用度低等问题,限制了其在食品及医药行业的应用。乳液凝胶兼具乳液和凝胶结构,有良好的稳定性,常作为天然活性物质载体,在功能食品及医药领域中应用广泛。以酪蛋白(casein,CN)和海藻酸钠(sodium alginate,SA)为基质,通过一步均质法制备了含油量为80%(体积分数)的O/W型乳液凝胶,用于Cur负载,以改善其稳定性和生物利用度;研究了CN与SA比例对乳液凝胶的形成及结构的影响,分析了负载Cur的乳液凝胶贮藏、冻融、稀释、热以及离心稳定性;探究了乳液凝胶负载的Cur的模拟胃肠释放特性。结果表明,单一CN(质量分数为4%)作为基质时,可形成乳液凝胶;与SA(质量分数为2%)复合后,CN与SA体积比为9∶1至7∶3时可形成乳液凝胶。负载Cur的乳液凝胶油滴平均粒径由未添加SA的(86.00±6.31)μm减至(47.00±0.97)μm;单一CN基乳液凝胶油滴平均粒径为(107.00±7.54)μm,且在贮藏15 d后出现油析,而SA的添加显著提升了乳液凝胶的贮藏稳定性,其贮藏750 d仍然保持稳定,但冻融稳定性较差。在pH值为1.5、4.5和7.5水溶液稀释下,CN与SA体积比为9∶1至7∶3的乳液凝胶未出现油析。乳液凝胶具有较高的离心稳定性,且水合性随SA添加量的增加而增大。另外,乳液凝胶具有较高的热稳定性,在65、85℃下热处理1 h仍保持结构稳定。与游离Cur相比,经C N-SA基乳液凝胶负载后,Cur的胃肠释放率和生物可给率都显著提升,其中CN与SA体积比为7∶3时最高。研究结果旨在为Cur的负载和递送提供理论依据,为高稳定性乳液凝胶体系构建提供技术参考。

Curcumin(Cur)is a natural bioactive molecule with antioxidant,anti-inflammatory,hypolipidemic,and other biological activities,but the poor stability and low oral bioavailability of which limit its application in food and pharmaceutical industries.Emulsion gel has both emulsion and gel structures,as well as good stabilities,which is widely used in functional food and pharmaceutical industry as a carrier of natural bioactive molecules.In this paper,a O/W emulsion gel with an oil phase fraction of 80%was prepared by the one-step homogenization method using casein(CN)and sodium alginate(SA)as the matrix to loading Cur to improve its stability and bioavailability.The effect of CN to SA volume ratio on the formation and structure of emulsion gel was studied,and the storage,freeze-thaw,dilution,thermal and centrifugation stability of emulsion gels loading Cur were analyzed.The simulated gastrointestinal release characteristics of Cur loaded by emulsion gel were explored.The results showed that emulsion gels could be formed with CN(mass fraction of 4%)alone as matrix.After combined with SA(mass fraction of 2%),the emulsion gel could be formed at the CN to SA volume ratio of 9∶1 to 7∶3.The average particle size of oil droplets in emulsion gels loading Cur was reduced from(86.00±6.31)μm without SA to(47.00±0.97)μm.The average particle size of oil droplets in CN emulsion gel was(107.00±7.54)μm and the oil phase separated after 15 d storage,while the addition of SA significantly improved the storage stability of the emulsion gels which remained stable after 750 d storage.However,the freeze-thaw stability of CN-SA emulsion gels was poor.With the aqueous dilution at pH 1.5,4.5 and 7.5,the emulsion gels with CN to SA volume ratio from 9∶1 to 7∶3 kept stable.Moreover,the emulsion gels had good centrifugation stability,which water holding capacity increased with the increasing of SA addition.The emulsion gels based on C N-SA had high thermal stability,which microstructure remained stable after heat treatment at 65 or 85℃for 1 h.Compared with free Cur,the gastrointestinal release rate and bioaccessibility of Cur loaded in emulsion gels based on C N-SA were significantly increased,and the emulsion gel with a CN to SA ratio of 7∶3 had the highest gastrointestinal release rate and bioaccessibility of Cur.The results could provide theoretical basis for loading and delivery of Cur,as well as the technical reference for system construction of high stable emulsion gels.