Four groups of male rats were fed diets containing 20 % (by weight) palm oil, palm middle fraction (PMF) by dry-fractionation, palm super olein (PSO) by double-dry-fractionation and soybean oil as the control, for 28 d. Comparative studies were made on serum lipids, cholesterol and its metabolites in tissues and feces from the rats. The physical and chemical properties of dietary fats were also examined. 1) As major components, PMF contained mono oleoyl dipalmitin (POP) and mono palmitoyl diolein (P00), and PSO contained POO, POP and palmitoyl linoleoyl alein (PLO). Compared with palm oil, PMF showed more solid fat content (SFC) at 5°C and less SFC at temperature exceeding 20°C, the reason being that PMF contained more 2-oleoyl-1, 3-disaturated acylglycerols and less saturated triacylglycerols with the highest melting point. SFC of PSO showed 0 % at 5°C owing to the presence of more monosaturated-diunsaturated acylglycerols whosemelting points were low. 2) All four groups were essentially the same in cholesterol content in serum (total and HDL), liver and adipose tissue. Analysis of fatty acids in fecal lipids indicated the apparently preferential excretion of palmitic acid into feces in the PMF and PSO groups, as was also noted for the palm oil group. 3) Cholesterol content in feces from the PMF and PSO groups was basically the same as that in palm oil group, but less than that in the control group. This was also noted for coprostanol, lathosterol and some bile acids. The ratio of total metabolites/cholesterol in feces was essentially the same in all groups. 4) The effects of PMF and PSO on cholesterol metabolism are shown by the present results to be equivalent to those of palm oil, and possibly the same as those of soybean oil.
The autoxidation of soybean oil was effectively inhibited by the addition of a commercial free oxygen absorber (FOA) of the iron powder type into the headspace and/or oil phase in a flask closed with a rubber stopper. Increase in peroxide value (POV) during storage at room temperature for 4, 6 or 10 months was almost completely suppressed by FOA added to the headspace or both headspace and oil phase in a sealed flask (0.72.1 times that at the start). The decomposition of tocopherols (Toc) in soybean oils hardly occurred. POV of soybean oil, which is usuallypreserved in a flask (blank test), remarkably increased (20.8410.5 times that at the start), and Toc was reduced to about 40 % the initial level at 10 months of storage. On opening the sealed flask, can or bottle, the soybean oil preserved by FOA was found to be more resistant to autoxidation than new soybean oil not pretreated with FOA. The dissolved free oxygen in the oil is thus shown to substantially accelerate autoxidation. The preservation of soybean oil by FOA sealed with polyethylene (PE) film was assessed for the prevention of oil penetration into the absorber, since such penetration deactivates the absorber and may cause migration of iron and other substances from FOA into the oil. The addition of FOA sealed with PE film into the headspace of the flask inhibited increase in POV (to about 1/41/3 that of blank), but it was less active than that of the uncovered absorber (about 1/20 that of blank). The addition of FOA sealed with PE film to the oil phase in a sealed flask slightly depressed increase in POV (about 1/32/3 that of blank). The present results indicate FOA to be the quite effective for improving quality maintenance of edible oils.
The thermal polymerization and degradation of thin films of trilinoleoylglycerol (TLG) (thickness 85 μm) on a iron cell plate (Fe cell) and silica cell plate (SiO2 cell) under nitrogen were investigated by vacuum thermal gravimetric analysis (VTGA) using dynamic thermal programs. The results obtained are as follows. 1) The thermal polymerization of thin films of TLG in the Fe and SiO2 cell was started at 160 °C and the rates of the reactions were quite rapid at 230°C and 250°C under nitrogen respectively. 2) The rate constants and apparent activation energy of the thermal polymerization of TLG in the Fe cell were 1.23 × 10-3 -2.40 × 10-3 wt %/s and 11 kcal/mol in temperature ranges of 200°C to 230°C, and 2.40 × 10-3 -8.75 × 10-3 wt %/s and 33 kcal/mol of 230°C to 250°C, respectively. For TLG on the SiO2 cell, these parameters were 2.22 × 10-4 -6.94 ×10-4 wt %/s and 53 kcal/mol from 160 °C to 250°C, and 6.94 ×10-4 -24.1 × 10-4 wt %/s and 126 kcal/mol of 250°C to 270°C, respectively. 3) The thermal decomposition of thin films of TLG on the Fe and SiO2 cells were initiated at 220°C and 240°C, respectively. The reaction rates were very fast at 240°C and 270°C under nitrogen, respectively.
The electron spin resonance (ESR) spectra of n-doxylstearic acid (nNS : n=5, 7, 12, 16) in abinary system of 3- [2-hydroxy-3- (isooctadecyloxy) propoxy] -1, 2-propanediol (DGE) and water were measured to examine the behavior and orientation of nitroxy radicals modified by stearic acid in lamellar type liquid crystals (LC) formed by highly hydrophobic surface-active agents, such as alkyl glyceryl ethers. With increasing water content in LC, the order parameter of nNS (n=5, 7, 12) and correlation time of 16 NS decreased. Increment in the mobility of the DGE hydrophylic group by the addition of water would thus appear to influence the overall mobility of DGE molecules. A comparison of the relative mobility of each nNS indicated that the curvature of the DGE monolayer in contact with water in LC change continuously with increasing water content. The mobility of nNS in a DGE/water and GE/water system and changes in structure of lamellar type LC formed by DGE are thus demonstrated by the present results.
Betaines were prepared from amides of N, N-dimethy1-1, 3-propanediamine and lauric acidor hardened coconut oil fatty acids. The viscosity of a shampoo frame formulation containing only betaine and sodium dodecyldi (oxyethylene) sulfate (SDES) as surfactants was found to increase 2000 mPa·s with the addition of 0.06 % lauric acid. Increase in viscosity was proportional to fatty acids added. A determining facter of viscosity was found to be component fatty acid in the range such as that for the present betaine preparation.