Supercritical carbon dioxide (SC-CO2) is a suitable substance to extract non-polar substances (triacylglycerols). However it has not proven effective in the extraction of polar substances. The efficient use of SC-CO2 and ethanol mixture to extract and fractionate phospholipids from salmon fish roe was therefore investigated. Extraction was performed at low pressure and temperature (17.7 MPa and 33°C) to avoid oxidation of polyunsaturated fatty acids. Phospholipids were not found to be extracted with 0- and 5%-ethanol in SC-CO2. However extractions with 10, 15 or 20%-ethanol in SC-CO2 were effective in extracting phospholipids. The amount of extracted phospholipids increased with increased addition of ethanol. When the extraction was performed with SC-CO2 and 20%-ethanol mixture, more than 80% of the phospholipids were recovered.
The aim of the present paper is to correlate the relative antioxidant activity of catechins and their incorporation in soybean phosphatidylcholine (sPC) membranes. For the purpose the inhibition effect of the catechins (+)-catechin (C), (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC), and (-)-epigallocatechin gallate (EGCG) on α-Tocopherol (α-Toc) consumption was compared when the lipid oxidation was initiated in the aqueous medium by the water-soluble radical initiator 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) or in the lipid phase by the lipophilic 2,2′-azobis(4-methoxy-2, 4-dimethylvaleronitrile) (Meo-AMVN). The catechins C, EC, EGC, ECG and EGCG at a concentration of 15 μM were added exogenously to the water medium of multilamellar (MLV) liposomal suspensions or were incorporated in the lipid phase of MLV or unilamellar (ULV) liposomes, containing incorporated α-Tocopherol (α-Toc) at the same concentration. The α-Toc and catechin consumption were followed by high-performance liquid chromatography (HPLC) technique. The inhibition the accumulation of lipid hydroperoxides (LOOH) by catechins in ULV oxidized by AAPH also was studied. The antioxidant activity of catechins, expressed by the constant of inhibition kinh, and the parameters n and kclinh were determined. The galloylated catechins ECG and EGCG, inhibiting α-Toc consumption in greater extent in MeO-AMVN - than in AAPH-oxidation, were better incorporated in lipid membranes, and also had higher peroxyl radicals scavenging activity than the non-galloylated C, EC, and EGC. ECG being the most effective catechin protecting α-Toc against lipophilic radicals interacted most efficiently with PC layers as well as ECG was the strongest radical scavenger. In hydrophilic radicals-initiated oxidation EGCG incorporated in MLV layers protected α-Toc better than ECG, and was consumed faster than ECG when incorporated in ULV liposomes. EGCG was situated closer to the lipid/water interface than ECG. The EGCG derived radical was more prone to participate in side propagation reactions. The cis-form EC had higher affinity for lipid membranes than the trans-form C, as EC had greater effect sparing α-Toc consumption in MeO-AMVN oxidation than C. EGC, the least effective among the studied catechins to preserve α-Toc from oxidation, was worst incorporated in lipid layers, and its radical was unstable leading to side propagations. In conclusion, the catechins interacted with PC membranes, and preserved α-Toc from oxidation by cooperating with it to scavenge peroxyl radicals or by regenerating it from its radical.
An attempt was made to orderly arrange a large number of polystyrene particles dispersed in aqueous medium on the electrode surface and fix the formed particle arrangement. The measuring cell used consisted of two transparent indium tin electrodes 500 μm apart from each other in the vertical direction. The gap between the electrodes was filled with a dispersion of polystyrene particles (5 μm size) and the behavior of the particles in electric fields applied between the electrodes was on-site observed with an optical microscope. Simultaneous application of DC and AC fields caused polystyrene particles to form single-layered clusters each consisting of several tens particles on the lower electrode. Densely arranged clusters were formed for the particles with polyallylamine hydrochloride (PAH), a cationic polyelectrolyte, adsorbed on their surface upon application of DC and AC fields and the clusters formed remained unbroken after removal of the fields. No cluster formation was observed, however, for the particles after adsorbing the cationic polyelectrolyte and then poly (sodium styrenesulfonate) (PSS), an anionic polyelectrolyte. These findings suggested that particle arrangement and its fixation of polystyrene particles are appreciably affected by polyelectrolyte adsorption.
Fluorescence quenching using N-sulfopropylacridinium (SPA) makes it possible to determine the degree of micellar counterion binding (β) of alkylpyridinium iodide in aqueous solution. But with quinoline derivatives as a halide-sensitive fluorescence probe, this was not possible. Fluorescence was quenched by iodide ions as indicated by linear Stern-Volmer plots, the slope of which was noted to decrease beyond cmc owing to micellar counterion binding with SPA excitation at 416 nm. The slope was found to significantly increase beyond cmc with SPA excitation at 357 nm. The abrupt quenching was due to absorption bands resulting from charge-transfer interactions of pyridinium and iodide ions. SPA fluorescence was quenched by iodide and bromide ions but virtually unaffected by nitrate or sulfate ions. Selective counterion binding of iodide ions is thus shown to be detectable.
D-Psicose, a C-3 epimer of D-fructose, is one of the “rare sugars” present in small quantities in commercial carbohydrate complex or agricultural products. In this study, we investigated effects of supplemental D-psicose on glucose tolerance and secretion of adipocytokines in rats fed a high-fat diet versus a low-fat diet. Twenty-four male Wistar rats (4 weeks old) were divided into four groups. Each group was fed a high-fat (25% fat) or a low-fat (5% fat) diet containing 5% D-psicose or cellulose for 16 weeks. Abdominal adipose tissue weights and carcass fat content were greater in rats fed the high-fat diet. However, D-psicose supplementation did not increase body fat accumulation compared to cellulose. Glucose tolerance decreased with time, and D-psicose supplementation did not improve glucose tolerance. Leptin, adiponectin and tumor necrosis factor-α levels in serum were the same among the four groups. These results suggest that supplemental D-psicose has no anti-diabetic effect in rats.
In order to improve the nutritional value of rotifers as the feed for juvenile fish, a yeast, Pichia methanolica HA-32, enriched with docosahexaenoic acid (DHA) was fed to rotifers. The composition of the cultivation medium (pH6) for enrichment of yeast with n-3 highly unsaturated fatty acids were as follows; 5% glucose, 2% yeast extract, 0.5% choline, 1% K2HPO4, 3% free fatty acid rich in DHA. Yeast was incubated at 25°C for 3 d. After incubation, the yeast contained 246 mg of total lipids and 69 mg of DHA per g dry cells. The DHA content in the rotifers cultured with the DHA-enriched yeast reached a maximum after 6 h-feeding. As a result, when 8.0 g (wet basis) of the DHA-enriched yeast (DHA content 170 mg) in 10 L of cultivating water was fed to 800 individuals/mL of rotifers and cultivated for 6 h, 240 mg of total lipids, 51 mg of DHA and 15 mg of EPA in rotifers were recovered. Moreover, the accumulation of DHA in rotifer by feeding the DHA-enriched yeast was more efficient than that by the commercial powdered oil containing the comparable amount of DHA to the DHA-enriched yeast.
New liquid crystals and organogelators with a cholesteryl benzoate skeleton were prepared. Cholesteryl 4-alkoxy- and 3,4-dialkoxybenzoates had enantiotropic cholesteric and smectic A phases, while 3,5-dialkoxy- and 3,4,5-trialkoxybenzoate derivatives were not mesomorphic. Furthermore cholesteryl 4-alkoxy- and 3,4-dialkoxybenzoates gelled organic solvents such as 1-decanol and n-hexadecane.