Middle East Technical University, Department of Food Engineering, Ankara, Turkey; University of Georgia, Department of Food Science and Technology, Athens, USA.
Middle East Technical University, Department of Food Engineering, Ankara, Turkey.
Int J Biol Macromol. 2019 Oct 1;138:473-482. doi: 10.1016/j.ijbiomac.2019.07.106. Epub 2019 Jul 17.
Having various domains of applicability, liposomes have been the issue of many studies since 1960s. Kinetically stable nature of liposomes required incorporation of other substituents to gain storage stability and interaction of liposomes with polymers, electrolytes, proteins or lipids still requires further investigation to explain the underlying mechanism. In this study, polyphenol-rich green tea extract was encapsulated into liposomes by means of microfluidization in two different aqueous media (pH = 3.8 acetate buffer and pH = 6.5 distilled water). Antioxidant loaded vesicles were further mixed with anionic biopolymers (gum arabic, whey protein) and cationic biopolymers (lysozyme, chitosan) separately. The physical and chemical interactions between liposomes and biopolymers were rationalized by particle size, zeta potential, transmission electron microscopy, total phenolic content and antioxidant activity measurements during 28-days storage at 4 °C. Experimental results indicated that the biopolymer incorporated liposomes showed better stability compared to control liposomes during storage, developing resistance against changes in particle size and zeta potential. On the other hand, biopolymer interaction mechanisms were shown to be different for different biopolymers. As was also proved by transmission electron microscopy, lysozyme was absorbed into the liposomes while gum arabic, whey protein and chitosan were adsorbed on the vesicle surface to shield green tea extract loaded liposomes.
脂质体具有多种应用领域，自 20 世纪 60 年代以来，一直是许多研究的课题。为了获得储存稳定性，脂质体的动力学稳定性需要掺入其他取代基，并且脂质体与聚合物、电解质、蛋白质或脂质的相互作用仍需要进一步研究，以解释其潜在机制。在这项研究中，通过微流化在两种不同的水介质（pH=3.8 乙酸盐缓冲液和 pH=6.5 蒸馏水）中将富含多酚的绿茶提取物包封到脂质体中。抗氧化剂负载的囊泡进一步分别与阴离子生物聚合物（阿拉伯胶、乳清蛋白）和阳离子生物聚合物（溶菌酶、壳聚糖）混合。通过在 4°C 下储存 28 天期间的粒径、Zeta 电位、透射电子显微镜、总酚含量和抗氧化活性测量，合理化了脂质体和生物聚合物之间的物理和化学相互作用。实验结果表明，与对照脂质体相比，在储存过程中，掺入生物聚合物的脂质体显示出更好的稳定性，对粒径和 Zeta 电位的变化具有抵抗力。另一方面，生物聚合物的相互作用机制因生物聚合物的不同而不同。正如透射电子显微镜所证明的，溶菌酶被吸收到脂质体中，而阿拉伯胶、乳清蛋白和壳聚糖则被吸附在囊泡表面，以保护负载绿茶提取物的脂质体。
