The objectives of the present study were to test the new analytical method, which has been developed by Urakami et al., for evaluation of oils used for frying various food items, simulating conditions actually encountered in family cooking and to compare the results obtained with those of model systems reported previously. Food items used were parsley, fritters of carrot and burdock, sweet potato, cuttlefish, and shrimp. They were fried continuously for 35min. per batch at 160180°C and frying was repeated 11 times, allowing the used oils to stand at room temperature for varying lengths of time. P/AP (the absorbance ratio of a polar one fraction at 233nm to apolar), AV, IV, and viscosity were determined at intervals. Despite some fluctuation of the last 3 values, particularly after standing 4 months, P/AP valnes showed a steady increase. This results give the good reliability for the new method in evaluation of an extent of deterioration. Large amounts of water depleted from food items and their large surface areas promoted deterioration of oils in such a manner as to give similar P/AP value in half of the period required for previous model system.
The catalytic addition reaction of diester of maleic acid to safflower fatty acid methyl esters by flow method was investigated. It was found that the addition of dimethyl maleate to safflower fatty acid methyl esters was easily carried out by continuously passing the mixed sample of the ester and dimethyl maleate at molar ratio of 1 : 1 over a high surface-area synthetic silica-alumina catalyst composed of 70% of SiO2 and 29% of Al2O3. From the analytical results by GLC, the addition products were known to be mainly consisted of two compounds (adduct I and II in Fig.-2) at produced ratio of ca. 1 : 1. And each adduct separated by column chromatography was analyzed to have a cyclohexene ring structure, respectively, by IR, NMR and MS spectral measurement. Then, adduct I was confirmed to be formed by the Diels-Alder addition of dimethyl maleate to conjugated octadecadienoate, and adduct II was also noticed to have a structure produced with the Diels-Alder addition of maleic anhydride to the octadecadienoate. The formation process of adduct II was further discussed.
A differential scanning calorimeter (Perkin Elmer DSC-1B) has been applied to the thermal investigation for phase change phenomenon of 1-bromooctadecane, and different behavior in the transition of this bromide has been observed at different thermal treatments. The phase transition phenomenon was found at cooling process. The transition temperature, 19°C, was consistent with that expected from the result of previous studies in a series of normal higher primary bromides containing 22, 24, 26 and 28 carbon atoms. The value of transition entropy is close to those of 1-bromodocosane and 1-bromotetracosane. This transition behavior could be explained by the example of these compounds. The phase transition of this bromide can be regarded as rotational one. The behavior of these DSC curves is explained by the aid of free energy-temperature schematic diagram. The metastable low temperature phase which first appeared below the transition point at cooling changed into stable one, irreversibly. The sample of this stable state, as well as the recrystallized sample, revealed no phase transition phenomenon in heating process. In cooling process, a exothermic peak have been observed when the sample is held at a constant temperature on high temperature phase. The energy calculated from this peak was nearly equal to the latent heat of phase transition of this bromide. The high temperature phase is considered to be metastable one and changes to stable phase spontaneously. Dielectric constant measurements were carried out using a transformer bridge at 10kHz. No phase transition phenomenon was observed both in cooling and heating processes. There was the discrepancy between the results of DSC measurement and that of dielectric constant one, This is possibly due to the metastable state of high temperature phase and the difference of precision in temperature control for both measurements.
1, 4-Diketones were prepared from allylidene diacetate [I] via six steps. The synthetic route is shown in Scheme-1. The addition of [I] to acetaldehyde gave 4-oxopentylidene diacetate [II] in 60% yield. 4, 4-Ethylenedioxypentanal [IV] was obtained from [II] in about 24% yield. 8-Undecene-2, 5-dione [VIIa] was prepared from [IV] and cis-3-hexenyl magnesium bromide in about 70% yield via 2, 2-ethylenedioxy-8-undecen-5-ol [Va] and 2, 2-ethylenedioxy-8-undecen-5-one [VIa]. Similarly, 2, 5-undecanedione [VIIb] was formed from [IV] in 70% yield. cis-Jasmone and dihydrojasmone [VIII] were formed from 1, 4-diketones [VII] in 85% yield.
The present paper described the studies on removal of fatty acids from cotton fabrics by alkaline builders. Cotton fabrics were soiled with the fatty acid mixture, which contained equal amounts of lauric, myristic, palmitic, stearic, and oleic acid in benzene solution. Fatty acids adhered to cotton fabrics were determined by GLC method after extraction with ethyl ether. Fatty acids were effectively removed by alkaline builders alone, but addition of sodium dodecylbenzene sulfonate (ABS) did not increased the efficiency of removal. Removal of fatty acids was compared at two different temperatures, 25°C and 50°C. They were removed much easier at 50°C than at 25°C. This was considered to be due to the difference in the state of fatty acid mixture at the two temperatures, because the melting point of the fatty acid mixture was measured as to be 40.8°C. Each fatty acid component was removed from cotton fabrics in the order of, C12>C14>C18 : 1>C16≥C18, at 25°C. On the other hand, at 50°C, the order was C12>C14>C16≥C18>C18 : 1. This concluded that a shorter chain fatty acid was removed easier than long chain fatty acids.
Conditions for measurement of the dropping point (MDP) of edible solid fats with Mettler FP-5/FP-53 were examined, and comparative examinations were made on MDP of unhardened solid fats and those with different degree of hardening, and their Wiley melting point (WMP) and clear point (CP) obtained by the conventional method of measurements. The results obtained were as follows : 1) The measured values of MDP tended to become higher with faster rate of temperature rise, and MDP value agreed approximately with CP and WMP when this rate was 1°C/min. MDP was not affected by the heat treatment, or by the temperature at which the measurement was started. 2) The measured values of MDP of unhardened solid fats and those with different degree of hardening were in approximate agreement with CP and WMP. In addition, the dispersion of measured values was extremely small. 3) There was a significant (0.1% level) positive, first-order correlation between MDP of beef tallow and coconut oil with different degree of hardening and their CP and WMP values. Consequently, MDP seems to be a very useful method for the measurment of a melting point of solid fats in comparison with WMP and CP.