The rates of phase transition of tristearin have been studied by X-ray diffraction. (1) In solid phase of triglycerides, α-form transformed into β near mp of α, The rates of transition α→β were determined and the activation energy was obtained. (Table 1, Fig.-2) (2) When tristearin melted with triolein, tricaproin or liquid paraffin, it seemed that tristearin was dispersed in the liquid oil. In this case, it was observed that the rate of the transition α→β of tristearin was faster and the activation energy was smaller than that of the solid. It was also observed that the larger the ratio of the liquid to the solid, the faster the transition rate was. IIowere, it was concluded that the activation energy was independent on the ratio of the liquid. (Fig.-3-5, Table-3) (3) When the solid phase of tristearin existed in an organic solvent such as alcohol, chloroform etc. time rate of transformation α→β of tristearin was faster in the solvent that has higher soluhility. (Fig.-7) In conclusion it was believed that the rate of transition α→β of tristearin in equilibrium with its organic solution or oil was dependent on the size of tristearin and the solubility.
It has been observed tlint iso-linoleic acid in partially hydrogenated linseed and soybean oils is responsible for the development of characteristic hydrogenation flavor. In the present paper, authors investigated whether isomerized soybean fatty triglycerides caused the hydrogenation flavor. Three types of isomerized soybean fatty triglycerides were prepared as follows. 1) Trans isomerized soybean oil was prepared by treatment with nitrous acid. (trans isomer 61.5%) 2) Triglyceride which contained positional isomers was prepared by esterification of glycerine with hydrazine-reduced soybean fatty acid. (9, 15-iso-linoleic 1.4%) 3) Triglyceride which contained both trans and positional isomers was prepared by esterification of glycerine with hydrazine-reduced and trans-isomerized soybean fatty acid. Hydrogenated soybean oils having the I.V. of 116.2, 71.2 and 55.1, respectively, were also prepared by selective hydrogenation of soybean oil with nickel catalyst. Reversion flavor of isomerized and hydrogenated oil was evaluated organoleptically under the following conditions whether it contained hydrogenation flavor or not. 1) Flavor evaluation was made during heating at 120°C. 2) Flavor evaluation was made after storage under diffused sun light for 10 days. It was found tlint hydrogenation flavor was detected only for hydrogenated soybean oil with L.V. of 116.2, 71.2 and 55.1, but not detected for other isomerized soybean fatty triglycerides. It was also postulated t hat t he precursor of hydrogenation flavor was not only iso-linoleic acid but also iso-oleic acid.
Coconut oil, palm kernel oil and their hardened oils were randomly rearranged in order to measure the change of softenning point (S.P.) by randomization and to measure the difference of S.P. by solidified condition. Randomized coconut oil obtained was higher in the S.P. than coconut oil, but other laurine oils resulted lower in the S.P. by randomization. Especially, hardened palm kernel oil resulted much lower. Rise in the S.P. of randomized oils was higher in the degree than non-randomized oils upon keeping the samples at2O-25°C for 3 days in the case of non-hydrogenated laurine oils, but on the contrary, they became lower in the degree than non-randomized oils in the case of hydrogenated laurine oils. Changes of S.F.I. and triglyceride composition by gas chromatography and pancreatic lipase hydrolysis were also investigated. It was postulated that the reason why S.P. resulted in lower degree by randomization was due to decrease of a small quantity of high melting triglyceride, considering from changes of S.F.I. and triglyceride composition by GLC.
Four trihy droxy-octadecenoates (T) were separated from sesame oil (SO) and methyl linoleate (ML) subjected to UV irradiation or oxygen bubbling by column and thin-layer chromatography. From the results of IR, NMR, MS and elemental analysis, two out of the four were identified as methyl 9, 10, 13-trihydroxy-11 (trans) -octadecenoates. The remainder methyl 9, 12, 13-trihydroxy-14 (trans) -octadecenoates (in the case of SO, after methylation), and the two compounds in each group were estimated to be stereoisomeric one another. In addition, the mechanism of their formation was clarified using ML and it proved that T were produced from ML through such intermediates as methyl linoleate hydroperoxides (H) and methyl hydroperoxy-epoxy-octadecenoates (E). T was quite stable against UV light and prolonged autoxidation.
The effects of the mixing of various types of surfactants on the dispersion in aqueous systems of an azo-type disperse dye at high temperatures have been studied as a function of the mixing ratio of surfactants. The dispersion of the disperse dye in mixed surfactant solutions depends strongly upon the chemical composition of ionic surfactants, especially, surfactants with phenolic hydroxyl group, and the cloud point of nonionic surfactants. In general, the addition of surfactants, having a complex chemical composition and phenolic hydroxyl group in the molecule, e.g., the Na salt of formalin condensate of creosote oil sulfonic acid, tends to cause great influence on the dispersion of the dye suspended with other types of surfactants, while the addition of those having a simple chemical composition and no phenolic hydroxyl group, e.g., the Na salt of formalin condensate of β-naphthalene sulfonic acid, tends to cause little influence. Further, the addition of nonionic surfactants having a low cloud point causes great influence on the dispersion of the dye suspended with other types of surfactants, while the addition of those having a high cloud point causes little influence.