The object of this study is to, elucidate the difference of the frying quality of oils customary used in Japan in the condition without addition of antioxidant or synergist. Physical and chemical changes were compared with soybean oil, corn oil, cottonseed oil, rice oil, rapeseed oil, lard, palm oil and coconut oil in continuous water spraying and heating system (Table-1, Fig, -14). Thermal oxidative changes such as viscosity increasing ratio, carbonyl and iodine value, showed close relation with the initial iodine value of these oils. However, in coconut oil in spite of the low iodine value, the carbonyl value increased very rapidly. This fact suggests the oxidation of saturated fatty acid in coconut glyceride. On the other hand, hydrolytic changes observed in acid value was great with rapeseed oil, lard and palm oil and was very small with coconut oil and cottonseed oil. In the case of coconut oil, this result may depend on the high volatility of free fatty acid produced in the oil. In the case of cottonseed oil, the high stability to hydrolysis may depend on the cyclopropenoid fatty acid contained about 0.3% in the oil, similarly to that of kapok seed oil. The lowering of fat stability to autoxidation was observed as the deterioration proceeds. The rate of lowering was different by the kind of oils. Cottonseed oil and rice oil showed the smallest rate. In the case of lard, the fat stability was very low from the initial stage of test. This may depend on the low content of γ-tocopherol in lard. From these results, the author believes that the fatty acid composition, the behavior of antioxidant and hydrolytic property in the frying oils are the important factors affecting to the frying quatity.
In the previous paper, the authors suggested the presence of the aromatic ο-substituted compound in the cyclic monomer obtained from heated linseed oil in the presence of alkali. In order to certify the presence of the aromatic ο-substituted compound, this study was made by using ethyl-β-eleostearate prepared form tung, oil. Ethyl-β-eleostearate was heated at 250°C, for 10 hours in the stream of carbon dioxide. Heated ester was separated into non urea adduct forming ester and urea adduct forming ester by urea adduct separation. Cyclic monomer was obtained from non urea adduct forming ester by vacuume distillation. When GLC and IR spectra of this cyclic monomer were compared with those of the cyclic monomer of the first report obtained from heated linseed oil, the similarity was observed. IR spectra of this cyclic monomer indicated the presence of aromatic ο-substituted compound and cyclohexadiene structure. The positions of the both compounds on the GLC chart were ascertained by selective hydrogenation of this cyclic monomer. In the case of cyclic monomer obtained from ethyl-β-eleostearate heated under severe condition at 310°C for 10 hours, it was found in the GLC and IR spectra that the amount of aromatic ο-substituted compound increased, while the amount of cyclohexadiene compound decreased. With regard to the mechanism of the formation of aromatic ο-substituent, cyclohexadiene is farmed by the cyclization of ethyl-β-eleostearate, and aromatic ο-substituent is formed by disproportionation reaction of cyclohexadiene. From the result of the experiment on ethyl-β-eleostearate, it can be concluded that, when linseed oil is heated under the presence of alkali, (1) linolenic acid in linseed oil is isomerized to conjugated triene, (2) cyclization and (3) disproportionation reaction occure and aromatic ο-substituted compound is formed.
Many papers have been published about the nutritive value of polymerized oils using esters of those oils. However, it is still not clear whether esters prepared from polymerized oils have the exact nutritive value of original polymerized oils. In order to compare the nutritive values of polymerized oils and their esters, soybean and linseed oils were blown with air or nitrogen at 275±5°C for 12 hours and a part was esterified. The growth of rats fed both the thermally oxidized oil (TO) and the polymerized oil under nitrogen (PO) was less than the growth of those fed original oil, and TO showed lower nutritive value than PO. Ethyl ester prepared from TO depressed more the growth of rats than the original TO, whereas ethyl ester from PO showed almost the same growth with original PO before esteriflcation. Results indicate that ethyl ester from thermally polymerized oil can be used instead of polymerized oil for the determination of nutritive value, but ethyl ester of thermally oxidized oil can not be used.
A neutron activation method is proposed for the determination of trace quantity of copper, down to submicrogram level, in fats. The sample and standard are irradiated for 5 hr at a neutron flux of 1.7×1O12N·cm-2·sec-1. The radiochemical separation consists of extraction of induced activity of 64Cu in hydrochloric acid from toluene solution of the irradiated fat, followed by the anion exchange in hydrochloric acid media. The activity is finally mounted as copper (II) sulfide. The activity measurement is taken on a NaI (Tl) crystal coupled with a 256 channel pulse height analyzer. Radiochemical purity is satisfactory. The chemical yield averages 70.6%, and there is a considerable saving of time in the radiochemical work. The agreement is good for determinations of trace copper, by a colorimetric method preceded by dry ashing along with magnesium nitrate as an ashing aid, and by the neutron activation method. This method is therefore believed as giving a sound basis to the routine analytical work.
In the previous paper, the authors reported that the tocopherol concentrate composed of hydrocarbones, tocopherols, higher alcohols, fatty acid methyl esters and other components, was separated into six kind of fractions by employing TLC. It was recognized that there were two kind of reducing substances in those fractions containing hydrocarbones and other non-polar materials. In this paper, several concentrates were prepared by mixing to the deodorized condensate from the rice bran oil (4.8% tocopherol content) with the tocopherol concentrate (42.6% tocopherol content), each fractions were prepared by means of the same method as the previous report, and two kind of fractions, one of which contained A-1 component and another contained A-2 component mainly, were prepared by separating and purifying on TLC plate. The samples prepared by the above method were added to lard and then the effects on A.O.M. stability were examined. The following results were obtained : 1. Optimum condition in the case using the concentrate as antioxidant was found as that the tocopherol content (wt%) in the concentrate was 20 to 30%, and concentration added to lard was 0.05% as α-tocopherol. 2. Induction period of lard mixed with the fraction, composed of sterols and higher alcohols, etc., was shorter than that of the reference. However, induction period of lard mixed with the non-polar fraction was a little longer. 3. Antioxidant ability was seen in the two kind of fractions containing A-1 and A-2 components.
The adhering states of soils on the fiber surface were observed with optical and electron microscopes. The amount of large soil particles of diameter above 10 μ on the soiled cloth was comparatively less. From the electron micrographs it was observed that a number of small flat particles having the diameter less than 1 μ which can not be detected by the optical microscope, adhere on the fiber surface. The spectroscopic analysis of inorganic soils gave the spectra of Si, Al, Ca, Mg, and Fe as the strongest lines and the intensities of other lines were very weak. The electron and X-ray diffraction were also experimented for the composition of the inorganic soils. The analyses of the organic soils extracted from naturally soiled cloths were carried out by IRR spectroscopy, gas chromatography, thin-layer chromatograpy (TLC) and gel filtration. The existence of triglycerides, cholesterol and its ester and hydrocarbons such as paraffin and squalene in organic soil was identified by TLC. In the gel filtration, two peaks were found in elution diagrams of the detergent solution after washing naturally soiled cloths.