The monthly change of the fatty acid composition of lipids in the ascidian, Halocynthia roretzi was examined by GLC, before and after their fractionation into polar and nonpolar lipids. Lipids were extracted monthly from the edible parts and viscera of ascidian from April to March, and from the genital glands of ascidian from November to January. The lipid content in ascidian increased from September and decreased from January. The content in the genital glands was higher than in the edible parts and viscera. In ascidian lipids, polyunsaturated fatty acid (20 : 5 and 22 : 6) showed high value. The content of heptadecanoic acid was higher in lipids from the liver and genital glands than that of edible parts. The polar lipids contained much heptadecanoic acid while the neutral lipids, very little. The fatty acid composition of phosphatidyl choline and phosphatidyl ethanolamine, the main phospholipids, were, mainly composed of unsaturated acids, with polyunsaturated acid (20 : 5, 22 : 6) predominant. The compositional percentages of fatty acids somewhat fluctuated, but the variation according to season was not clear.
Tocopherols (Tocs), dissolved in a mixture of trilaurin (Tri-La) and trilinolein (Tri-Li) in varying proportions, were oxidized with air at 180°C for a fixed period of time. The concentrations of the remaining Tocs and their dimers formed in the reaction mixture were determined by HPLC. The oxidative stability of Tocs decreased with increasing concentration of Tri-Li in a triglyceride mixture. When phosphatidyl choline (PC) was added to the triglyceride mixture at a concentration of 0.1%, the Tocs were stabilized remarkably even in a triglyceride mixture containing a large amount of Tri-Li. (Figs.-2, 3 and 4) The amounts of dimers formed from Tocs changed with the ratio of Tri-La to Tri-Li. The changes to diphenyl ether type dimers from r-and 5-Tocs was particularly great. These dimers attained maximum amounts when the proportion of Tri-Li in a triglyceride mixture was 510%. The amount of biphenyl type dimers changed little (Figs.5-, 6 and 8). In the presence of PC, very small amounts of the diphenyl ether type dimers were formed in relatively constant quantities during the thermal oxidation of γ-and δ-Tocs, regardless of the proportion of Tri-Li in the triglyceride mixture (Figs.-7 and 9).
The wetting phenomena of various surfactant solutions using the felt disc were studied in relation to hydrophile-lipophile (H/L) balance. In the case of the nonionic surfactants of a series of POE nonylphenyl ethers, the wetting ability of surfactants depend on HLB number, for which there was an optimum range. Since a surfactant with an HLB number in this range gave a cloud point in aqueous solution in the vicinity of the temperature of wetting test, the balance of surfactant H/L properties may be important in achieving maximum wetting ability. Ionic surfactants containing branched, or two long-chain alkyl goups such as Aerosol OT usually exhibit high wetting ability. In the pseudo three component system, brine/n-decan/Aerosol OT, the increase in concentration of NaC1 caused the H/L balance of Aerosol OT to shift lipophilically and the three phase region appeared at 0.640.75 wt% of NaCl. Wetting ability improved by the addition of NaCl, and the highest was attained at a certain concentration of NaCl. However, further addition caused it to decrease. Thus the wetting properties of a surfactant can be explained from the standpoint of H/L balance ; that is, the surfactant whose H/L properties are exactly balanced easily gives a three phase region containing the surfactant phase, and lowers considerably the O/W interfacial tention to attain high wetting ability.
It was reported in a previous paper that the peroxide value (POV) of a small amount of lipid can be determined by potentiometry in the JOCS tentative method for POV. The previous method was further modified in the present work to reduce the required amount of saturated potassium iodide aq. solution used for iodometry. Consequently, the time for titration was less, and the end point of titraion clearer, thus giving more reliable results. By the present method, it was possible to determine accurately the POV of a lipid extract from ca. 3 ml of human serum. Moreover, by the thiobarbituric acid (TBA) test for measuring peroxides indirectly, detection of peroxides in serum was possible at levels of less than 20% of the value by the present method. The present method makes possible the direct determination of a small amount of hydro-peroxide in serum lipid and thus makes it easier to understand the influence of lipid peroxidesin vivo on cancer, strokes, atheriosclerosis, the aging process etc.
The fatty acid composition of lipids in the dorsal muscle of chum salmon, Oncorhynchus Keta, was examined by GLC, before and after fractionation into polar and nonpolar lipids. The contents of fatty acids, 16 : 0, 18 : 1, 20 : 5, and 22 : 6 in chum salmon dorsal muscle were high. The tendency for compositional percentage to vary with time, place and sex could not be clarified in the present experiment.
The fatty acid composition of lipids in the viscera of chum salmon, Oncorhynchus keta was examined by GLC, before and after fractionation into polar and nonpolar lipids. The contents of polyunsaturated fatty acid, such as 20 : 5 and 22 : 6, were high in chum salmon viscera lipids. The compositional percentages of the fatty acids of lipids in the examined viscera, liver, heart, kidney, genital gland, digestive organs differed somewhat.