Non-acidic volatile decomposition products from hydrogenated coconut oil used for deep fat frying were studied. The oil developed distinctive coconut-like flavor by heating for frying. Volatile products were seperated from the oil by vacuum steam distillation and further refined by molecular distillation. Distilled products were separated into four fractions by TLC. Each fraction was identified by IR, GC and MS. They were n-alkanes with carbon numbers 10 to 17, n-alkanals and 2-alkanones C5 to C13 and γ-lactones C5 to C13. Among those, compounds with odd number of carbon atoms had higher peak in gaschromato-gram for alkane and carbonyl compounds, and compounds with even number of carbon atoms had higher peak for γ-lactone. Mechanisms for formation of these compounds were discussed.
In the previous paper, thermally oxidized oil (TO) was fractionated by silicic acid column chromatography and the authors manifested that the toxic substance was eluted with diethyl ether. This paper deals with further study of the structure of the toxic compound. From the results of elementary analysis and from several characteristics of the toxic compound, it seemed to have two carbonyls, two hydroxyl groups and epoxide group in one molecule, but the presence of aldehyde and cyclic compounds was not recognized. This compound was presumed to be dieter of glyceride by the determination of molecular weight, NMR and mass spectrometry. A dimer of fatty acids was obtained by the molecular distillation of fatty acid methyl ester of the dimer glycerides. This dimer of fatty acids formed by heating was not bonded by oxygen-bridge, but by carbon-carbon bond. As a result, the toxic compound may, presumably, have the following structure. * Yukagaku, 19, 486 (1970)
In previous papers1)2), authors reported that unsaponifiable matter and free fatty acids in thermally oxidized soybean oil (TOSO) gave little effect for the taste of TOSO. The present paer deals with the effect of glycerides on the taste of TOSO. After the separation of free fatty acids from TOSO using alkaline solution, the oil was fractionated by molecular distillation and submitted for organoleptic evaluation. In spite of the high viscosity, the residue (MW : 2239) was almost tasteless. The distillate was fractionated by silicic acid column chromatography. The fraction eluted with 60% IPE had “heated oil like”taste. From such results, glycerides with some functional groups are assumed to be responsible for the taste of TOSO. 1), 2) Yukagaku, 18, 252 (1969); 19, 10, (1970)
Homogeneous hydrogenation of soybean oil or methyl ester derived from linseed or cottonseed oil has been studied using complex catalysts [Co (CO) 3PR3] 3 (PR3 is P (n-Bu) 3, P (Cyclohexyl) 3 or PPh3, and the catalysts are abbreviated here (1), (2) or (3) respectively) which are known to hydrogenate cyclododecatriene into cyclododecene with almost complete selectivity in the presence or absence of small amounts of carbon monoxide. In the title reaction, however, addition of ca. 25 atm of carbon monoxide to 4050 atm of hydrogen was essential to secure high selectivity and to prevent catalyst decomposition. Under these pressures the typical figures of reaction time (min) / reaction temperature (°C) were 120/170, 350/145 or 60/185 employing 0.30.8 mol% per ester of (1), (2) or (3) respectively without solvent. Addition of benzene as solvent remarkably accelerates the rate of reaction using (3). Catalyst (3) was appraised as best, because, different from (1) and (2), it does not form saturated products even after unnecessarily delayed reaction and moreover, it can be recovered through timely discontinuance of the reaction. Regardless of the kinds of starting, esters a total amount of ca, 10% of two unidentified peaks was always observed in the gas chromatograms of final products. Remaining ethylenic linkage was widely distributed over monoenoic fatty acid chain on either side of C9 position, and its trans/cis isomer ratio was ca. 1.75. Formation of small amounts of “Oxo-alcohol” was also observed.
The reaction of vinylmagnesium chloride with various fatty acids gives a mixture of new unsaturated ketone and divinyl alkyl carbinol. For example, from n-butyric acid, a mixture of 3-n-propyl-3-hydroxyl-1, 4-pentadiene and 5-oxo-1-octene was obtained in a total yield of 64%. Similarly, a mixture of unsaturated ketone and divinyl carbinol was obtained from other fatty acids.
The Biodegradation test method of anionic surfactants was established in 1967 and revised in 1968 as JIS K-3363. This method is only applicable to synthetic detergents primarily composed of alkyl benzene self onates, alkyl sulfate, alkyl polyoxyethylene ether sulfate, alkane sulf ovate and alkenyl self ovate. Establishment of the test method for nonionic surfactants was also desired at that time and is now under progress by the Biodegradation Sub-committee of the Society. This report covers present situation developed in the past two years in our sub-committee as interim report Biodegradation of several typical nonionic surfactants such as nonyl-phenol ethoxylate, lauryl alcohol ethoxylate, lauroyl di-ethanol amide, nonyl-phenol polypropylene ether as well as dodecene-1 derived LAS as a standard sample, was evaluated by physical and chemical analysis using shake culture and semi-continuous procedure. Test results indicate that polyoxyethylene group is degradable as shown by foam reduction, cobalt thiocyanate method and GLC observation of residue. This may suggest as long as foam pollution is concerned, nonionic surfactants such as nonyl-phenol ethoxylate are biodegradable. Further study is being conducted to elucidate pathways of degradation in connection with complete degradation.