Dynamics of unloaded and green tea extract loaded lecithin based liposomal dispersions investigated by nuclear magnetic resonance T-2 relaxation

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 (T-2) relaxation times and relaxation spectra were used for characterizing green tea extract loaded and unloaded liposornes 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 T-2 relaxation times. The differences in particle sizes of E80 and S75 samples along with samples with different homogenization pressures could be monitored with T-2 relaxation times. Additionally, T-2 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.


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Large, membrane-bound vacuoles of plant cells are suitable organelles for the compartmentation of ions. These vacuoles contain Na+/H+ antiporters for movement of Na+ within the organelle in exchange for H+. They provide an efficient mechanism to prevent the occurance of detrimental outcomes of Na+ accumulation in the cytosol. Identification of AtNHX1 gene that confers resistance to salinity by expressing a Na+/H+ antiport pump facilitates the understanding of the salt stress tolerance mechanisms of plants. ...
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Uyar, Ebru Ozer; Hamamcı, Haluk; TÜRKEL, SEZAİ (2010-08-01)
Rhizopus oryzae accumulates and degrades trehalose in response to environmental stress conditions such as heat, osmotic stress, nitrogen starvation and pH. When heat stress was applied to R. oryzae, the trehalose content of the cells was increased from 0.9 to 4.8 mg/g dw and when the stress was relieved it decreased back to 1.1 mg/g dw. Under osmotic stress and nitrogen starvation, trehalose content was increased by 3.5 and 3 fold, respectively. The decrease in external pH increased trehalose level up to 2....
Influence of nickel (II) and chromium (VI) on the laboratory scale rotating biological contactor
Taseli, B. K.; Gökçay, Celal Ferdi; Gurol, A. (Springer Science and Business Media LLC, 2008-09-01)
High concentration of heavy metals is toxic for most microorganisms and cause strict damage in wastewater treatment operations and often a physico-chemical pretreatment prior to biological treatment is considered necessary. However, in this study it has been shown that biological systems can adapt to Ni (II) and Cr (VI) when their concentration is below 10 and 20 mg/L, respectively. The aim of this study was to evaluate the effect of Ni (II) and Cr (VI) on the lab-scale rotating biological contactor process...
Effect of pectin methyl esterase (PME) and CaCl2 infusion on the cell integrity of fresh-cut and frozen-thawed mangoes: An NMR relaxometry study
Kırtıl, Emrah; Öztop, Halil Mecit; Barrett, Diane M.; McCarthy, Michael J. (Elsevier BV, 2014-12)
This study describes the use of Nuclear Magnetic Resonance (NMR) relaxometry to understand the effect of pectin methyl esterase (PME) + CaCl2 infusion under different conditions on cell integrity of fresh-cut and frozen-thawed mangoes. Infusion experiments were performed at: atmospheric pressure, vacuum conditions of 50 kPa and 10 kPa. For NMR relaxometry experiments T-2 (spin-spin relaxation time), T-1 (spin-lattice-relaxation times) and 2D T-1-T-2 experiments were performed. Results showed that, as the se...
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Eker-Develi, E; Kıdeyş, Ahmet Erkan; TUĞRUL, SÜLEYMAN (2006-01-01)
The effects of nitrate, ammonium and phosphate on the abundance, chlorophyll a content (chl a), in vivo fluorescence, particulate organic carbon, nitrogen, phosphorus and cell morphology of the diatom Skeletonema costatum, the dinoflagellate Prorocentrum micans and the coccolithophore Emiliania huxleyi were investigated in the laboratory. The carbon:chlorophyll a ratio (as weight), a parameter often used in productivity estimates, differed substantially among the three species as well as at different nutrie...
Citation Formats
E. Kırtıl, S. Güner, and H. M. Öztop, “Dynamics of unloaded and green tea extract loaded lecithin based liposomal dispersions investigated by nuclear magnetic resonance T-2 relaxation,” FOOD RESEARCH INTERNATIONAL, pp. 807–814, 2017, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/47441.