A study to optimize the use of oleoresin rosemary extract (OR), sage extract (OS) and citric acid (CA) in flaxseed oil during heating was performed using response surface methodology (RSM). Results showed that the natural antioxidants used in this study retarded oil deterioration, as evidenced by retention of fatty acids profiles. Results from this study revealed that the addition of OR and OS effectively retarded flaxseed oil deterioration after 20 times of frying of potato chips. Five type of fatty acids, namely C16:0, C18:0, C18:1, C18:2 and C18:3 were found in the oil, with all fatty acids having very good correlations with addition of natural antioxidants used during the frying. Mathematical models to predict the fatty acid composition of flaxseed oil after the frying could be developed with high confidence for all types of fatty acids. Therefore, for optimization purposes, the use of the ratio of saturated to unsaturated fatty acids was chosen because it covers all individual fatty acids present in the oil. After 20 fryings, the ratio best predicted the efficacy of natural antioxidants in preserving flaxseed oil with R2 of 0.954. Further analysis showed that after 20 fryings, all three antioxidants had a significant effect on the ratio. Based on these results, a combination of 0.064% oleoresin rosemary extract, 0.061 sage extract and 0.041% citric acid can be recommended for use in flaxseed oil before deep-fat frying.
The crystallization of Palm Oil and the thermal features of this process were examined. The manner in which Palm Oil crystals melted was noted to differ significantly with temperature, particularly in the case of crystallization at 10°C. Triacylglycerin in Palm Oil is comprised of POP (1,3-dipalmitoyl-2-oleoyl-glycerol) at 30% and POO (1,2-dioleoyl-3-palmitoyl-glycerol) at 20%. Examination was thus made of the crystallization of pure POP and POO and a mixture of these by differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). DSC patterns of the POP/POO (60/40) mixture and Palm Oil crystallized at 10°C were noted to be essentially the same. The mixture crystallized at 10°C showed 64 Å and 43 Å spacings by XRD, thus indicating triple-chain length and double-chain length structures to be present only in crystals formed at 10°C while only the double-chain length structure to be present in crystals produced of other temperatures. These findings would possible be explanation for variation in triacylglycerin content in crystals and why the POP/POO (60/40) mixture behaves in the manner of Palm Oil.
Addition of lipophilic polyoxyethylene dodecyl ether (C12EOn) to the dilute micellar solution of polyoxyethylene phytosterol (PhyEOm m = 10 and 20) results in the increase in viscosity. The increase in viscosity is attributed to the C12EOn induced one-dimensional micellar growth leading to the formation of worm-like micelles. Steady and oscillatory shear rheological measurement in PhyEOm + C12EOn (n = 2-5) shows that on decreasing the EO chain length of C12EOn, in general, the one-dimensional micellar growth becomes increasingly favorable. However, with very short EO-chain, for example, C12EO2, phase separation occurs at a lower concentration before significant micellar growth can be induced. In the systems of C12EO3 and C12EO4, the wormlike micelles entangle to form a viscoelastic transient network having a dynamic rheology that can be described by Maxwellian model in wide range of shear frequency. It was found that increasing the concentration or decreasing the EO-chain length of PhyEOm in the mixed system favors one-dimensional micellar growth. Comparison of the rheological behavior of PhyEOm + C12EOn systems with that of polyoxyethylene cholesterol (ChEOm) + C12EOn systems at similar conditions shows that in the former system C12EOn can induce micellar growth more effectively, which is attributed to the additional branching of the alkyl chain in the lipophilic moiety of the amphiphile.
The adsorption of a rod-shaped (rectangular parallelpiped) surface-active particle at a liquid-liquid interface has been theoretically studied. The adsorption energy, which is the free energy of the interface adsorbing the particle, is governed by the interfacial tensions between the particle and the liquids and the particle shape. The aspect ratio of the rod-shaped particle determines its adsorbing direction at the interface. The rod-shaped particle having aspect ratio larger than unity adsorbs in parallel direction with the liquid-liquid interface, while the plate-shaped one having the aspect ratio less than unity does perpendicularly. These theoretical results are important to understand the effects of the particle shape on the behavior of the surface-active particles in the self-assembled structures.
Dynamic light scattering studies on Ostwald ripening and composition ripening were performed in n-decane-in-water emulsion and squalane-in-water emulsion. Ostwald ripening was observed in n-decane-in-water emulsion, in which smaller droplets were more significant than larger droplets because of higher solubility of smaller droplets. When smaller droplets presence with larger droplets in emulsion, Ostwald ripening of larger droplets was enhanced, indicating that higher solubility of smaller droplets led to Ostwald ripening. Composition ripening was observed after mixing an n-decane-in-water emulsion and an squalane-in-water emulsion. Size decrease of n-decane droplets was always observed even though size of squalane droplets was smaller than that of n-decane droplets. Namely, n-decane molecules always diffuse from n-decane droplets into squalane droplets due to relatively high solubility of n-decane in water than that of squalane. These findings suggest that composition ripening more significantly contributes to droplet growth than Ostwald ripening (size dependent does).
Examination was made of the title effects in water, methanol and aqueous solutions of micelles and liposomes. Lysine (Lys) scanning decapeptides each containing norleucine (Nle) and alanine (Ala) were synthesized and their conformations determined by circular dichroism (CD). Conformational transition from α-helix to β-structure was noted in nearly every decapeptide. Each decapeptide was examined for its capacity to form amyloids by fluorescence using Thioflavin T. Increase in fluorescence was clear indication of the high capacity of Ala-Nle-Ala-Lys-Ala-Ala-Ala-Ala-Nle-Ala (2-9X4K) to form amyloids. Decapeptide interactions with acidic liposome were assessed based on entrapped 5(6)-carboxyfluorescein (CF) leakage. Leakage capacity of Ala-Nle-Ala-Ala-Ala-Ala-Lys-Ala-Nle-Ala (2-9X7K) was found greater than that of 2-9X4K.
Fine metallic soap particles synthesized by jet mixing process have a much narrower particle size distribution and more homogeneous surface structure than metallic soap particles prepared by the method of pulverizing and classifying. With jet mixing, reaction conditions can be adjusted so as to control particle sizes while maintaining the above characteristics unchanged. With these particles it is possible to examine in detail the relationship between the particle size and condition and the crystalline condition and other physical properties, which has been considered impossible to perform using metallic soaps prepared by the conventional method of pulverizing and classifying. So, using fine particles of fatty acid zinc salt as a model of metallic soap for structure analysis, the influence of average particle size and fatty acid composition were examined on crystallinity, heat characteristics and other properties of the particles. Diffraction intensities, half-band widths, and long spacings of Miller index (003) peaks were analyzed from X-Ray Diffraction chart and compared with average particle size and fatty acid composition for fine particles of fatty acid zinc salt. Furthermore, Crystallinity of fine particles of fatty acid zinc salt were examined by these results, and were compared with results of differential scanning calorimetry and specific surface area analysis. The results are described in the present report.