Dynamics of unloaded and green tea extract loaded lecithin based liposomal dispersions investigated by nuclear magnetic resonance T2 relaxation. (September 2017)

• Record Type: Journal Article
• Authors: Kirtil, Emrah; Dag, Damla; Guner, Selen; Unal, Kubra; Oztop, Mecit H.
• Is Part Of: Food research international. Volume 99:Part 1(2017)
• Page Start: 807
• Page End: 814
• Publication Date: 2017-09
• Subjects: Liposomes -- TD-NMR relaxometry -- T2 relaxation times -- Microfluidization -- Stability; Food -- Analysis -- Periodicals; Food industry and trade -- Periodicals; Food industry and trade -- Canada -- Periodicals; Food Technology -- Periodicals; Food -- Periodicals; Food-Processing Industry -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Industrie et commerce -- Canada -- Périodiques; Aliments -- Recherche -- Périodiques; Food industry and trade; Canada; Periodicals; Electronic journals; 664.005
• DOI: 10.1016/j.foodres.2017.06.064
• Languages: English
• ISSNs: 0963-9969

Abstract

Abstract: Liposomes are lipid bilayer vesicles that can be used as encapsulation systems for bioactive agents to provide increased protection against environmental stresses (such as pH or temperature extremes). Time Domain Nuclear Magnetic Resonance (TD-NMR) that is based on differentiation of specimen contents with respect to magnetic relaxation rates provides detailed information on amount, state and distribution of water and oil and provide reproducible results on the samples. These make TD-NMR particularly suitable for time-dependent monitoring of emulsion system dynamics. In this study, spin-spin (T2 ) relaxation times and relaxation spectra were used for characterizing green tea extract loaded and unloaded liposomes prepared with soy (S75) and egg lecithins (E80) by different preparation methods (such as homogenization type, pressure and solvent type). Mean particle sizes of liposomes were found to be the most influential factor in shaping mono-exponential T2 relaxation times. The differences in particle sizes of E80 and S75 samples along with samples with different homogenization pressures could be monitored with T2 relaxation times. Additionally, T2 relaxation times were found to be correlated with particle shape irregularity, and chemical instability of samples due to lipid oxidation. With relaxation spectrum analysis, particular components in the sample could be distinguished (internal/external water and lipid bilayers), which gave more elaborate results on mechanisms of instability. Graphical abstract: Highlights: Green tea extract loaded and unloaded liposomes were prepared. Microfluidization and ultrasonication were used to make liposomes. T2 times were related with the changes in particle size of liposomes. NMR relaxometry indicated different proton compartments in liposomes.