When whale meat or fish is fried in vegetable oil, an unstable oil which effused from the above foodstuff to frying oil accelerates the deterioration of frying oil. In the present work, thermal deterioration of corn oil contaminated with fish oil was studied. Corn oil, to which fish oil was added to give the final concentration of 0, 10, 20 and 40%, was heated in an oil bath controlled at 180±1°C under the condition of specific surface area 0.256cm2/g. Iodine value of the oil containing fish oil in high concentration decreased rapidly, and the color development of the oil by heating became more remarkable as the fish oil concentration increased. On the other hand, by the addition of fish oil a slight influence was observed in the change of acid value, carbonyl value and viscosity. Furthermore, the enlargement of surface area accelerated the thermal deterioration of contaminated oil. The contaminated oil was subject to autoxidation as compared with corn oil and the effect of fish oil in autoxidation was more remarkable than that in thermal deterioration. During the course of thermal deterioration, highly unsaturated fatty acids decomposed rapidly, but the decomposition rate of dienoic acids was low. Monoenoic acids were more stable than polyunsaturated acids in thermal treatment. When corn oil was heated, the stability in autoxidation decreased in parallel with the tocopherol content, but tocopherol in the contaminated oil decomposed more slowly than that of the oil without fish oil, and the stability of the contaminated oil even before heating was observed to be very low.
When TBA method is applied to oxidized lipids, red color (about 530nm) and yellow color (about 450nm) are produced. The red color is rather stable and is used for the analysis, but the yellow color is unstable. An attempt was made to solve the mechanism of producing the yellow color by comparing the results of Sidwell's method (mainly red color) and Ottlenghi's method (2 colors). The reaction of hydroperoxides with TBA and the reaction under addition of Na2SO3 were also tested. From these experiments, the compound developing yellow color was deduced to be caused by an aldehyde which came from a primary decomposed product of hydroperoxides by further oxidative decomposition.
Thermal reaction of safflower oil fatty acid methyl esters or methyl linoreate in the presence of iodine yields a remarkable amount of methyl octadecenoates. For the purpose of clarification of the source of hydrogen which is required for the formation of octadecenoates, the components of the reaction products by the thermal reaction of safflower oil fatty acid methyl esters in the presence of iodine (200°C, 2hr) were identified by means of GC-MS method. The results show that isomers of ω- (o-alkylphenyl) carboxylic acid methyl ester, dehydro-and Diels-Alder adduct type dimers of C18 fatty acid methyl esters, a few different types of C18 iodofatty acid methyl esters and a little amount of decomposition products such as alkanes, alkyl-benzenes etc. are present in the reaction products. It is postulated that the hydrogen which will evolve in the course of formation of ω- (o-alkyl-phenyl) carboxylates and dimers makes a main role as hydrogen source for the formation of octadecenoates.
A rapid and precise method for the determination of microamounts of cadmium, copper, nickel and manganese in fats and oils has been studied. The samples were decomposed by wet-digestion procedure using sulfuric acid and hydrogen peroxide (30%), then, cadmium and other metals in the decomposed solution were extracted into methyl isobutyl ketone as the complexes with sodium diethyldithiocarbamate. The extracts were directly atomized into the air-acetylene flame, and the absorbances were measured at 228.8nm for cadmium, 324.7nm for copper, 232.0nm for nickel and 279.5nm for manganese. The most suitable pH for the extraction of these metals was about 7, and these metals were quantitatively extracted into methyl isobuthyl ketone by once extraction. The proposed method was evaluted with respect to recovery and reproducibility by carring out collaborative studies on the samples which were prepared by adding known amounts of cadmium and other metals to soybean oil. The results thus obtained showed good agreement with the theoretical values and satisfactory reproducibility.
Effects of metal chlorides and oxides on the autoxidation of methyl oleate and the decomposition of hydroperoxides of methyl oleate at 80°C were investigated by observing the changes in peroxide, iodine, saponification, acid and hydroxyl values and oxirane oxygen during the autoxidation of methyl oleate in the presence of benzoyl peroxide (0.1%) and the chlorides or oxides (0.05% as metal) and decomposition of hydroperoxide of methyl oleate in the presence of nitrogen under the same condition. MoCl5, VCl3, VCl4 and V2O5 decomposed hydroperoxide of methyl oleate remarkably, and produced little peroxide. On the autoxidation of methyl oleate and the decomposition of hydroperoxide, the epoxides and hydroxides were produced remarkably. MoCl5 and V2O5 seemed to produce less acids than VCl3 and VCl4. Further, the effect of each metal compound seemed to be slightly different. WCl6 decomposed hydroperoxide of methyl oleate slowly, and produced epoxides and hydroxides in the presence of nitrogen. However, WCl6 in the presence of air had a little effect. CrCl3·6H2O affected the autoxidation of methyl oleate remarkably, and produced epoxides and hydroxides. On the decomposition of hydroperoxide of methyl oleate, CrCl3·6H2O decomposed hydroxide slowly, but didn't produce epoxides and hydroxides. One of the products of the autoxidation of methyl oleate in the presence of CrCl3·H2O was a low molecular acid and the effect of CrCl3·6H2O seemed slightly different from the other metal compounds. MoO3 and MnCl2 didn't accelerate the autoxidation of methyl oleate and the decomposition of peroxide. The each effect of the compounds of periodic group 5, 6 and 7 transition metal was dissimilar.
Authors found that N-acylethylenediamines obtained by the reactions of the methyl esters of C812 fatty acids with ethylenediamine readily cyclizes on heating to yield 2-alkyl 4, 5-dihydroimidazoles. The following results were also obtained with this finding. The type of the principal product obtained from the reaction between the methyl ester of a fatty acid with ethylenediamine in ethanol was dependent on the method of separation of the reaction product; namely, the solvent extraction afforded the N-acylethylenediamine and the distillation under reduced pressure afforded 2-alkyl-4, 5-dihydroimidazol.
The effect of some surface active agents on bacteria was morphologically investigated using an electoron microscope. Cationic, anionic or nonionic surfactant was added to the suspensions of E. coli in physiological solution of sodium chloride and transmittance of the suspension was determined at 560mμ. With the cationics which exhibited a marked antibacterial activity, the transmittance decreased significantly as the concentration of the surfactant increased from 6.25μg/ml to 100μg/ml. The transmittance of the suspensions containing anionics of 100μg/ml was same as that of control suspension containing no surfactant, and the transmittance of the suspension containing cationics showed the lowest. The suspension of E. coli treated with the surfactant was centrifuged in a refrigerated centrifuge to prepare the specimens for an electron microscope observation. According to figures of the electron microscopy, it was found that the cell, especially cell wall and protoplasm, suffered considerable changes such as swelling of cell, disappearance of undulation and bleb formation in cell wall, decrease or granular aggregation of ribosomes, or formation of lamellar structure in the plasma membrane.
Dodecyl and tetradecylbenzoic acids were prepared by oxidation of the corresponding alkyl-acetophenones derived from acetylation of alkylbenzenes. These acids were neutralized with various bases including alkali metal hydroxides and aminoalcohols such as 2-aminoethanol, 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1, 3-propanediol, tris (hydroxymethyl) -aminomethane and triethanolamine. Surface activities of these salts were determined and compared with each other. These salts showed excellent lowering power of surface tension, except triethanolamine and tris (hydroxymethyl) -aminomethane salts. Most organic salts had larger value of cmc than inorganic salts. 2-Aminoethanol salts of both acids and 2-amino-2-methyl-1-propanol salt of dodecylbenzoic acid showed excellent emulsifying power for benzene, and for kerosene 2-aminoethanol and 2-amino-2-methyl-1-propanol salts of the acids proved to be better emulsifier than the other salts, but all of these salts emulsified moderately soy-bean oil as well as DBS (sodium dodecylbenzenesulfonate). 2-Aminoethanol salt and potassium salt of dodecylbenzoic acid showed better wettability than other salts, but inferior to DBS. Foaming properties of these salts were found not good.
For the purpose of clarifying the effects of the structure and the number of carbon atoms of esters on the development of Seborrhea, the oleic acid esters of mono-hydroxyalcohol having side chains were prepared and fed to rats at a level of 15% of the feed. When (1) iso-propyloleate, (2) tert-butyloleate, (3) tert-amyloleate, (4) iso-amyloleate, (5) 1, 3-dimethylbutyloleate, (6) 2-methylhexyloleate, (7) 2-methylheptyloleate, (8) 3, 7-dimethylocta-2, 6-dienyloleate were used, development of Seborrhea was observed in all cases. The carbon numbers of the all sample esters above mentioned were less than 28. In the previous experiments, when saturated straight monohydroxyalcohol esters of oleic acid were used, although the carbon number was less than 28, there was no symptom of Seborrhea. In the case of the ester of tertiary type mono-hydroxyalcohol, a remarkable development was recognized particularly in (2) and (3).