The influence of static magnetic field on crystallization of triacylglycerols (TAGs) was investigated. Melted TAGs were solidified under static magnetic field of 5 T with a superconductive magnet system. Polymorphic behavior of TAGs was examined by temperature modulated differential scanning calorimetry (TMDSC) and X-ray diffraction (XRD). In TMDSC experiment, saturated mono-acid TAGs (PPP and SSS) had no change in crystallization behavior under static magnetic field. Static magnetic field processing suppressed the crystallization of α form of SOS, PPO and POS. Furthermore, it suppressed the crystallization of sub-α form, α form, and β ′ form of POP. In case of SSO, the crystallization of α form and β ′ form was suppressed. On the other hand, in the XRD experiment the crystallization of α form in PPP and POP was suppressed by static magnetic field processing. PPO had no change in crystallization behavior under the static magnetic field. However, fluctuation in the ratio of the XRD peak area (wide angle region/small angle region) of α form was increased. This change suggested that the phase transition from α to β ′ form had occurred. From these results, the following can be considered as the influences of static magnetic field on crystallization of TAGs: (i) the effect of static magnetic field on crystallization of saturated mono-acid TAGs depended on the fatty acid chain length which constitutes TAG (PPP and SSS), (ii) the shorter the acyl chains of TAGs, the more sensitive to static magnetic field it was in saturated-unsaturated mixed-acid TAGs (PPO and SSO), and (iii) symmetrical type TAGs (POP and SOS) were more sensitive to static magnetic field rather than asymmetrical type of TAG (POS). It is speculated that the effect of a magnetic field on polymorphism of TAGs is due to the magnetic field gradient in a magnet and the molecular orientation caused by magnetic anisotropy of a TAG molecule. Much work is needed to clarify the mechanism of the polymorphic crystallization under static magnetic field.
Oleyl oleate, a liquid wax ester was synthesized by an immobilized Candida antartica lipase B (Novozym 435) as biocatalyst using oleic acid and oleyl alcohol. The effects of various reaction parameters were optimized to obtain a high yield of liquid wax esters. Investigation in large scale production was performed in batch mode of stirred tank reactor (STR) with one multi-bladed impeller. The optimum condition to produce liquid wax ester was, reaction time (RT); 30 min, temperature (T); 50 °C, amount of enzyme (E); 90 g (900,000 PLU), agitation speed (A) of 400 rpm, number of impeller tip (N) of 2 and molar ratio of oleyl alcohol to oleic acid (M); 2:1. Analysis of the yield showed that at optimum condition, >90% liquid wax esters were produced. The stability of Novozym 435 showed at high percentage (>80%) up to 4 cycles.
In this study, we investigated the effects of two types of polyglycerol fatty acid esters, both of which were made from the same polar group of polymerized 10 glycerols, on the crystallization of n-hexadecane (n-HD). One of the emulsifiers, known as THL-17, consists of three different saturated fatty acid chains with different carbon numbers between 8 and 18. Another emulsifier, known as 10G10S, contains a stearic acid chain only. The two emulsifiers were added to retard the crystallization rate of n-HD, which has melting point of 18.0°C, and was chosen as a model fat material. Visual and optical microscopic observations showed that the growth of n-HD seed crystals in bulk liquid was significantly retarded by the addition of 1.0 wt.% THL-17 at 17.0°C. The DSC cooling peaks of n-HD with and without the addition of THL-17 showed that the crystallization temperature (Tc) of n-HD decreased with increasing concentrations of THL-17 from 15.9°C (in the pure form) to 14.0°C (in the solution containing 1.0 wt.% THL-17). In contrast, 10G10S did not affect the Tc value, even at a concentration of 1.0 wt.%. The results of this study suggest that the inhibition of n-HD crystal formation in the presence of THL-17 results from effects on both crystal nucleation and post-nucleation crystal growth processes.
Evening primrose oil, which includes GLA, is one of the most popular of many treatments available for PMS. It has been reported that diagnosis of PMS on the basis of prospective daily rating is essential. However, few studies on alleviation by GLA of the symptoms of PMS have been performed using prospective daily rating. We examined the alleviating effect of GLA on symptoms of PMS diagnosed by prospective daily rating. Twenty-eight women diagnosed with PMS consumed vegetable oil containing about 180 mg/day of GLA for three luteal phases in a randomized, double-blind, parallel protocol, and were examined for duration and severity of PMS symptoms. Levels of DGLA in plasma phospholipid were significantly lower in women with PMS than in those without it (DGLA, P < 0.01) before treatment regardless of phase in menstrual cycle. After GLA administration, the levels of GLA and DGLA in plasma phospholipid in the GLA group were significantly higher than those both in the placebo group and before treatment. Improvement of the duration and severity of PMS symptoms as a whole, as well as that of irritability, was significantly more pronounced in the GLA than in the placebo group. These findings indicate that GLA can be effective for treating the symptoms of PMS, and that GLA and DGLA in plasma phospholipid may play a role in the onset of PMS.
A decapeptide Ala-Nle-Ala-Lys-Ala-Ala-Ala-Ala-Nle-Ala showed conformational transition from α-helix to β-sheet and further formed amyloid fibrils in a micellar environment in previous work with lysine-scanning decapeptides. In the present work we used norleucine-scanning decapeptides to evaluate amyloid formation under the same conditions. The decapeptides were synthesized, and their conformations were determined by circular dichroism (CD). Conformational transition from α-helix to β-structure was noted in nearly every decapeptide. However, only the decapeptide Ala-Ala-Ala-Lys-Ala-Ala-Ala-Nle-Ala-Ala (8X4K), which has one norleucine (Nle) and one lysine (Lys) in an alanine(Ala)-based decapeptide, formed the β-structure immediately and not via α-helices. A series of norleucine-scanning decapeptides were examined for amyloid-forming capacity, by using a fluorescence dye, Thioflavin T. An increase in fluorescence was also a clear indication of the high capacity of 8X4K to form amyloids. The amyloid aggregates were observed by transmission electron microscopy (TEM) and identified as parallel β-sheet structures by fourier transform infrared spectroscopy (FTIR).
A water-soluble cationic 5,10,15,20-tetrakis(N-methylpyridinium-4- yl)porphinatomanganese(III) ion (MnT4MPyP) and water-insoluble 5,10,15,20-tetrakis(N-3-furyl)porphinatomanganese(III) ion (MnT3FuP) were prepared and ion-complexed with an anionic phospholipid membrane to enhance the circulation persistence of the porphyrin complexes in vivo. Fluorescence spectra and fluorescence depolarization experiments indicated MnT3FuP to be situated within the hydrophobic interior of the vesicle composed of the phospholipid membrane, while MnT4MPyP was anchored to the membrane by lipophilic tails with the metalloporphyrin head-group located on the interface between the membrance and aqueous solvent. SOD activity was determined by stopped-flow analysis and cytochrome c assay, which allowed the determination of IC50 and kcat values for the reaction of the metalloporphyrins with superoxide anion radical (O2-·). Sodium stearate-linked MnT4MPyP was the most effective catalyst as an SOD mimic to decompose O2-· at a second-order rate constant of 1.9×107 M-1s-1 in dimyristoylphosphatidylcholine (DMPC) liposomes. SOD activity of MnT3FuP was less than that of MnT4MPyP.
Autoxidation of triacylglycerol (TG) oil occurred most rapidly, whereas oils containing tocopherol (Toc) showed a slower increase compared to the ordinary TG oil. Autoxidation of oils was apparently delayed by addition of Toc and vitamin C (VC), and the effect of these antioxidants was greater in diacylglycerol (DG) oil than in TG oil. On the other hand, there was no apparent difference between DG and TG oils in the presence of Toc only. The ΔE values (color difference) of TG oils were higher than those of DG oils, and the values were lower in the oils containing both Toc and VC than in those containing only Toc. The carbonyl value (COV) of TG oil increased with aeration time and tended to be lower without Toc than with Toc. The peroxide value (POV) of DG oil did not change with aeration time, whereas POV of TG oil increased with aeration time and the amount of Toc. COV and the p-anisidin value (ANV) increased with the number of uses, however, the values of DG oils containing Toc tended to be lower than those of the other samples. The dehydration rate, weight decrease and moisture content tended to decrease with the number of uses, which might contribute to the oily or greasy taste of fried food. COV, ANV and the acid value (AV) showed significant correlation with each other, but not with oil absorption, dehydration rate, weight decrease or moisture content.
The shape of mixed dipalmitoylphosphatidylcholine (DPPC)/stearylamine (SA) liposomes prepared by the Bangham method was examined using freeze-fracture electron microscopy. The shape of the mixed DPPC/SA liposomes (XSA = 0.05) was not that of multilamellar vesicles (MLVs) but large unilamellar vesicles (LUVs) with a diameter of approximately 1.0 μm. These facts overthrow the preconceived idea that the shape of the DPPC/SA liposomes prepared by the Bangham method is that of MLVs. The trapping efficiency of the mixed DPPC/SA liposomes (XSA = 0.05) was ten times greater than that of the DPPC liposomes, since the DPPC liposomes were MLVs. The data of the DSC peak for the DPPC/SA liposomes also indicated that the shape of the DPPC/SA liposomes is that of LUVs. We emphasize that the shape of the DPPC liposomes changes from that of MLVs to LUVs by the mixing of a small amount of SA into the DPPC liposomes.