The object of this study is to elucidate the influences of temperature, amount of water sprayed and fat turnover rate on the deterioration of frying oils in the continuous water-spraying and heating systemr. The influence of temperature was examined at 160±2, 180±2 and 200±2°C in the existence of air, or in the state of protected fat surface by means of metal float as wide as possible (Table-1, Fig.-1, 2). It was observed that thermal oxidative deterioration (viscosity increasing ratio, Iodine V.) was more influenced by specific surface area exposed in air than temperature, however, hydrolytic deterioration (Acid V.) was influenced by temperature very significantly. On the contrary, the increase in carbonyl value was smaller at 200°C as compared with the case of the lower temperature. This suggests increased volatility of carbonyl compounds at 200°C. The influences of the amount of water sprayed and fat turnover rate were also examined (Fig.-3, 4), The increase of acid value was accelerated by the increase of the amount of water sprayed, and the viscosity increasing ratio was less influenced. Fat turnover rate acted effectively as the preventing factor on any thermal oxidative or hydrolytic deterioration.
The mechanism of rancid change of oil contained in instant Chinese noodle was investigated. Samples of noodle and those of oil used for frying the noodle were exposed to the sun light for various periods of time. The noodle samples were extracted with n-hexane after exposure. For characterizing the samples of oil and of extract, acid, peroxide, iodine and carbonyl values were measured. The change in these values was dependent on the length of exposure to the sun light. The toxic action was determined by peroral administration into mice. The oil samples exposed for 300 hours or longer caused diarrheal in mice.
Pure coconut oil of the same lot was divided into samples in the stages of crude oil, purified, semi-hardened, and hardened state, and each sample was stored at -20, 5, 15 and 30°C for 6 months. Values of A.V., P.O.V. and Co.V. were measured in every month, and their correlation with crystal growth was examined by electron microscopy observation. The same experiments were also carried out on a mixure of (a) hardened coconut oil added with hardened beef tallow or cotton seed oil and (b) hardened beef tallow mixed with non-hardened coconut oil or butter fat. 1) The values of A.V. rose in those stored at 15 and 5, in that order, and especially in the hardened oil. Practically no change was seen in those stored at -20 and 30°C. P.O.V. was zero throughout the test period, while Co.V. showed higher value with increasing storage temperature and less hardening. 2) Hardened coconut oil mixed with hardened beef tallow showed marked rise in A.V. while that mixed with cotton seed oil showed no change in A.V. values. When hardened beef tallow was mixed with non-hardened coconut oil, rise of A.V. value was about the same as that of hardened coconut oil. 3) Electron microscopic observation of hardened coconut oil showed that the roughness of crystal surface increased in the order of storage temperature of 15, 5, 30 and -20°C, which corresponded to the order of rise in A.V. values. The crystal surface of the oil stored at 5°C showed the presence of whiskers. In the oil stored at 15°C, single crystal had shown great growth and there was a space between that and the next single crystal. If a vapor is present in that space, absorptive reaction might occur in the singular face of the crystal. 4) The surface was smooth in non-hardened coconut oil, and liquid glyceride was found to occupy the spaces between single crystals. 5) In the hardened coconut oil mixed with hardened beef tallow, the crystal surface became rough, while the sample of hardened coconut oil mixed with cotton seed oil was similar to the hardened coconut oil stored at -20°C.
HLB values of polyoxypropylene-polyoxyethylene blockpolyether type of high molecular weight have not yet been determined (except an unreported study by Schmolka and Lutwick), pherhaps because of their high molecular weight and particular properties of hydrophobic radical (consisted of semi-hydrophillic oxypropylene units). HLB values of this type of nonionic surfactants were experimentally determined from required HLB value for solubilization of phenyl ethyl alcohol. Experimental attempt to determine HLB values from required HLB value for the emulsification was not successful. From comparison of the determined HLB values with cloud point (°C) or cloudy number (ml), the following empirical relations were obtained : HLB value=0.0980x+4.02 and HLB value= 16.02 log A-7.34 where, x=cloud point (°C), and A= cloudy number (ml). These empirical relations were independent on the number of functional -OH radicals of these nonionic surfactants of which molecular weights of hydrophobic polyoxypropylene per one -OH radical are larger than 9001, 000. If these molecular weights are smaller than 9001, 000, above empirical relations were not applicable. This suggests that polyoxypropylene radical per one -OH radical of smaller molecular weight than 9001, 000 behaves incomplete hydrophobic radical.
Biodegradabilities of anionic surfactants listed in Table-1 were investigated under aerobic and anaerobic conditions. Under anaerobic condition where the removal of organic substances took place slowly and incompletely, even surfactant sulfonates with straight alkyl chain were found to show low biodegradabilities. Among sulfates tested, there were some which proved ramarkable decrease in the methylene blue (MB) responsibility by anaerobic incubation. It was found by use of a sulfate, DAS, that the organic biodegradation intermediate was present in anaerobically incubated medium after the disappearance of MB-responce and that the amount of organic biodegradation residue found in earlier stage of aerobic incubation was much as compared with the estimate from the disappearance rate of the MB-responce. Therefore, enzymatic hydrolysis seemed to take part in the biodegradation process bisides the breakdown of its alkyl chain.
The properties of the seed-oil of Itachisasage and its components concerned with fatty acids and unsaponifiable matters were studied. The oil was obtained by extracting the dried seeds with ether, then treating with n-hexane. The yield of the n-hexane-soluble oil was 7.5% to the dried seeds and the properties were as follows; n21D 1.4764, I.V. 130.0, S.V. 187.0 and unsaponifiable matters 0.5%. The mixed fatty acids were obtained with 93.0% yield, and which were esterified to methyl esters with methanol and p-toluenesulfonic acid. The esters were treated with mercuric acetate, then seperated to saturated parts and unsaturated parts (mercuric acetate adducts) through silica gel column developing with benzene. The fatty acids in each parts analysed by means of gaschromato-graphy were as follows; C14F0 0.10%, C16F0 6.5%, C18F02.4%, C20F0 1.5%, C16Fx 0.20%, C18F110.8 %, C18F2 74.9%, C18F3 3.0% and C20Fx 0.6%. The sterol-percentage in the unsaponifiable matters was 31.3%, and the main sterol in them seemed to be β-sitosterol.