The solubilization of oily materials and/or oil dyes by water-soluble surfactants was studied in terms of the limit of solubilization, solubilizing power, cmc depression, viscosity, dielectric constants, electrical conductivity, electrophoresis, diffusion, surface tension and the heat of mixing. Differences in the solubilization mechanism and size of micelles due to different solubilizates, and the energy gap between solubilization and emulsion regions with increasing amount of solubilizate are discussed. Moreover, thermochromism and fading phenomena for solubilized solutions of oil dye are described.
A model triglyceride mixture was prepared by the random interesterification of hardened coconut oil. The mixture was analyzed by GC-MS, The fatty acid composition of each triglyceride group having the same total acyl carbon number was determined by the relative intensity distribution of the specific fragment ion containing one of three acyl groups of a triglyceride molecule. Correction of fatty acid composition was made using the correction factor from the GC-MS data of the standard diacid triglyceride. The fatty acid composition determined as by GC-MS agreed well with that by theoretical calculation according to random distibution of acyl groups and also agreed with that by conventional hydrolysis-GC.
Pyrolysis characteristics of five kinds of unsaturated triglycerides were investigated by ordinary and derivative thermogravimetry. 1) Weight reduction in tripalmitolein (PoPoPo), triolein (OOO) and trieicosenoin (EiEiEi) was initiated at 194°C and completed at 542°C under a stream of air. The processes involved in this reduction were more complicated than those for that of saturated triglycerides due to oxidative decomposition. On the other hand, reduction under a stream of nitrogen was similar to that of saturated triglycerides. 2) The weights of trilinolein (LLL) and trilinolenin (LiLiLi) increased as the temperature was raised from 100°C to 200°C under the stream of air, and the rate of increase in the weight of (LiLiLi) was higher than that of (LLL). The pyrolysis behavior of (LLL) and (LiLiLi) from 300°C to 400°C was more complicated than that of (OOO). 3) Volatile substances and residues recovered at the initial stage of pyrolysis (at 20% weight reduction) of the four triglycerides were analyzed. The main component of the volatile substances formed by heating under the stream of nitrogen was a fatty acid constituting the unheated triglyceride. Under the stream of air, a number of fatty acids was detected. In the case of heating under the stream of air, the solubility of the residues in ether became less on increasing the degree of unsaturation of triglycerides. Under the stream of nitrogen, the main component of ether-soluble fraction of the residues was the original triglyceride except for the case of (LiLiLi).
α-Monoisostearyl glyceryl ether (GE) is a surfactant with less solubility into water, and forms the lyotropic liquid crystal with a reversed hexagonal structure even at lower concentrations. GE was found to be such a characteristic emulisifier that it gave stable water-in-oil (W/O) emulsions against a coalescence of water droplets, even though the water content of the emulsion was extremely high. The emulsion became more stable as increased in the water concentration. The structure of the emulsions was investigated through the study of the ternary phase diagrams and the measurement of small angle X-ray scattering, indicating that the liquid crystalline phase composed of GE, water and oil was formed in the emulsion. The electron microscopic observation showed that the interfacial layer between oil and water phases in the emulsion was the liquid crystal. And in case of higher water concentrations, the continuous phase itself was composed of the liquid crystal. These interfacial layers are considered to be mechanically so tough that the W/O emulsions were stable against a coalescence of water droplets. Thus it was concluded that the W/O emulsions stabilized with GE was, in fact, water-in-liquid crystal (W/LC) emulsion.
To investigate the physical characteristics of recent household margarines, 19 brands of margarine and 6 brands of fat spread were measured for their hardness index by cone-penetration, hardness (R) by a Reometer, oil-off value, solid fat content (SFC), open-tubed melting point (EMP) and softening point by JIS (ESP) and clear point (MCP), dropping point (MDP) and softening point (MSP) by Elex and Mettler automatic melting point apparatus. 1) The hardness of margarine decreased in the order of high linoleic soft>common soft>carton hard>parchment hard. Fat spread tended to be softer than the soft margarine, but to soften more slowly with increase in temperature. No difference was observed in their softeess at 20°C or higher. Softer margarines tended to oil-off more easily and showed less SFC. However, although fat spread was softer, it showed greater SFC and less oil-off value than the soft margarine. 2) In MDP and MSP, few differences were observed in measurements on the product and oil phase. The former for fat spread clearly exceeded that of the latter. 3) Oil-off values were correlated with hardness indexes, but tended to scatter in a softer region of the hardness index greater than 200. The relationship of hardness (R) to oil-off value could be expressed as a hyperbola, indicating the latter to be lower than 1% at a hardness (R) exceeding 1000 and to rapidly increase at a hardness less than 200. 4) The hardness index and SFC at 10°C were correlated with total % of saturated fatty acid plus trans-18 : 1, and with total % of unsaturated fatty acid except trans-18 : 1. However, both values were closely correlated with total % of polyunsaturated fatty acid (18 : 2+18 : 3).