Examination was made of the amounts of squalene and fatty acid compositions of triacylglycerols (TG) and phospholipids (PL) in the flesh and liver lipids of five species of deep-sea teleost fish: the Pacific flatnose Antimora microlepis and the black mora Halargyreus johnsonii of morid cods and the roughscale rattail Coryphaenoides acrolepis, the pop-eye grenadier C. cinereus and the pectoral rattail C. pectoralis of whiptails. Liver specimens of these deep-sea teleost fish contained copious amounts of lipids (19.5-65.1%) which were composed almost entirely of TG (72.6-95.9%). Flesh samples contained small amounts of lipids (0.3-0.5%) with lower TG (0.9-1.4%) and higher PL (53.8-76.0%) content. In the livers and flesh, unsaponifiable matter from the neutral lipids comprised squalene (42.4-57.7% and 3.7-10.3%) and sterols (22.8-51.0% and 84.0-95.3%), respectively, and the squalene content of liver lipids corresponded to 0.57-1.76%. Component fatty acids in TG from liver lipids were characteristically rich in monoenes (59.5-73.0%) with 22:1n-11 (15.7-24.1%), 18:1n-9 (11.2-16.6%) and 20:1n-11 (8.7-10.9%) acids. Nevertheless, component fatty acids in PL from flesh lipids were rich in polyenes (37.6-44.2%) with 22:6n-3 (23.1-28.4%) and 20:5n-3 (8.7-8.8%) acids.
We studied the cooperative interaction between α-tocopherol, tocotrienols and astaxanthin, incorporated in soybean phosphatidylcholine (PC) multilamellar vesicles (MLV) against 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH), 2,2′-azobis (2,4-dimethyl-valeronitrile) (AMVN), or 1,3-morpholinosydnonimine hydrochloride (SIN-1) induced lipid peroxidation. Tocotrienols spared α-tocopherol consumption in hydrophilic or lipophylic radicals initiated oxidation. The combination of tocotrienols and astaxanthin had the greatest protective effect on α-tocopherol consumption in MLV, oxidized by the hydrophilic radical initiator. α-Tocopherol and tocotrienols protected astaxanthin against AAPH-, AMVN-, and SIN-1-induced oxidations. In the three oxidations α-tocotrienol was consumed first, followed by α-tocopherol and the tocotrienols in the sequence: β > γ > δ. Astaxanthin was consumed as fast as γ-tocotrienol in AAPH oxidation, as fast as α-tocopherol in AMVN oxidation, and before δ-tocotrienol in SIN-1 oxidation. In conclusion, α-tocopherol, tocotrienols, and astaxanthin cooperated in protecting against MLV lipid peroxidation. α-Tocotrienol was the most effective antioxidant among them. Astaxanthin was as effective as the chain-breaking antioxidants against lipid peroxidation.
A modified method has been developed for quantitative determination of total carbonyl compounds in frying oils without using benzene. The analysis is done by the reaction of 2, 4-dinitrophenylhydrazine (2, 4-DNPH) with aldehydes and ketones in 1-butanol (1-BuOH) for 20 min at 40°C. The optimal wavelength to determine the total carbonyl compounds is 420 nm where the 2, 4-dinitrophenylhudrazone (2, 4-DNP) derivatives from saturated and unsaturated aldehydes and ketones have the same molar absorption coefficient. When the modified method was applied for the estimation of total carbonyl compounds in frying oils by using 1-BuOH instead of benzene as a solvent, a good correlation with the conventional method was obtained. It was expected that the modified method could be substituted for the conventional method and be useful for evaluating the quality of frying oils.
The purpose of this study was to investigate the dispersal mechanism of soybean oil (SO) into phospholipid as a fat emulsion. SO was dispersed with soybean phosphatidylcholine (PC) using sonication and the dispersal mechanism was evaluated by characterizing the dispersed particles using dynamic light scattering, fluorescence spectroscopy and surface monolayer techniques. The dispersions in the SO mole fraction range of 0.1-0.7 were stable at room temperature for 3 days. A limited amount of SO was incorporated into PC bilayer membranes (approximately 5 mol%). The excess SO separated from the PC bilayers was stabilized as emulsion particles by the PC surface monolayer. When the PC content was less than the solubility in SO (mole fraction of SO: more than 0.8), the PC monolayer did not completely cover the hydrophobic SO particle surfaces. In the case, the particle size increased drastically and the separation into oil/water occurred. Therefore, the solubility between SO and PC and the coexistence of emulsion and liposomal particles are critically important for the stabilization of the particles in water.
It was attempted to prepare cis-9, trans-11 conjugated linoleic acid (c9,t11-CLA) and t10,c12-CLA concentrates that can be used as foods. A free fatty acid mixture (FFA-CLA) containing almost equal amounts of c9,t11- and t10,c12-CLAs was esterified with glycerol using immobilized Rhizomucor miehei lipase, and the resulting acylglycerols (Gly-CLA) were purified by molecular distillation. Contents of c9,t11- and t10,c12-CLAs in Gly-CLA were the same as those in FFA-CLA: c9,t11-CLA, 33.7 wt%; t10,c12-CLA, 34.5 wt%. Gly-CLA was first hydrolyzed with an equal weight of water and 1.0 U/g-mixture of Candida rugosa lipase, and c9,t11-CLA-rich FFAs were prepared by molecular distillation: purity of c9,t11-CLA based on the total content of c9,t11- and t10,c12-CLAs, 72.9%. Meanwhile, purity of t10,c12-CLA in acylglycerols was 65.0%. To further increase the purity, the acylglycerols were hydrolyzed again with 15 U/g-mixture of C. rugosa lipase, resulting in enrichment of t10,c12-CLA in acylglycerols (purity of t10,c12-CLA, 80.4%). Non-selective hydrolysis of t10,c12-CLA-rich acylglycerols with 200 U/g-mixture of C. rugosa lipase produced t10,c12-CLA-rich FFAs (purity of t10,c12-CLA, 81.5%). In addition, c9,t11-CLA-rich FFAs were successfully esterified with glycerol using immobilized R. miehei lipase, and c9,t11-CLA-rich acylglycerols can be synthesized (purity of c9,t11-CLA, 73.0%). The process was composed of reactions with C. rugosa and R. miehei lipases, which can be used for production of foods, and molecular distillation. Hence, the c9,t11- and t10,c12-CLA concentrates can be used as foods.
Kinetic resolution of 3-alkanol by Pseudomonas cepacia lipase-catalyzed transesterification has been studied using vinyl acetate as an acetylating reagent, five alcohols and different organic solvents. The optical resolution data did not fit the previously reported theory: the enantioselectivity (E : the enantiomeric ratio for the homocompetitive reaction) showed the maxima against the extent of conversion (c ) in all systems studied. The optical resolution of (S )-3-alkanol with above 95% of enantiomeric excess (ee ) was attained by controlling c , but only a moderate ee was observed in the resolution of (R ) isomer from the racemate, owing to low or moderate enantioselectivity. The resolution of enantiomers with high optical purity was carried out using enantiomerically enriched alcohol: the ee values of the resolved alcohols showed an excellent agreement with those determined by the previously reported equations using the optical resolution data. Based on these observations, optically pure (R )- and (S )-3-alkanols (ee ≥ 99%) were resolved from the racemates in a preparative scale by repeating the transesterification.
The absorbance and fluorescence of SafranineT (3, 7-Diamino-2, 8-dimethyl-5-phenyl phenazinium chloride) have been studied in a series of polar and nonpolar solvents. When non-aqueous solvents are gradually added to the aqueous solution of Safranine T (ST) the absorbance and fluorescence intensity are enhanced. By suitable treatment of data, it has been established that the dye forms weak complex with solvent molecules.