This research was carried out to find the kinds of compounds formed by the action of 30% H2O2 on saturated fatty acid esters. Methyl ester of palmitic-, lauric-, caprinic-, caprylic-, caproic-, valeric-, and butyric acid were reacted under various conditions, without catalyst. As the reaction products, lower mono- and di-carboxylic acids and lower carbonyl compounds were always recognised, and di-carboxylic acids were obtained with good yield, especially from lower fatty acid esters, under the condition of the mol ratio of methyl ester to hydrogen peroxide to be 1 : 11 or more, and over 30 hrs at the temperature of 95105°C. From the value of the fixed quantity of carbon dioxide that produced by these reactions, it was recognised that lower esters were more readily reactive than the higher homologue.
Methyl octadecatrienoate was isolated by fractional precipitation of the brominated glycerides and its methyl esters in organic solvents, and by fractional distillation of the methyl esters. This methyl octadecatrienoate had d254 0.9072, n25D 1.4745, M.RD. 90.53, S.V. 191.7, I.V. (Wijs) 261.7. Oxidation of methyl octadecatrienoate in acetone with KMnO4 gave monomethyl adipate, butyric acid and succinic acid. This indicates following formula for octadecatrienoic acid. CH3 (CH2) 2CH=CH (CH2) 2CH=CH (CH2) 2CH=CH (CH2) 4COOH.
Methyl hexadecatrienoate (I) and methyl hexadecatetranoate (II) were isolated by fractional distillation of the methyl esters and by fractional precipitation of its brominated methyl esters from organic solvents. (I) had d254 0.9159, n25D 1.4722, M.RD. 80.87, S.V. 212.4, I.V. (Wijs) 287.4 and (II) had n12D 1.4862, S.V. 213.9, I.V. 385.7. Oxidation of (I) in acetone with KMnO4 gave monomethyl adipate, acetic acid and succinic acid. Hexadecatrienoic acid has the formula of CH3CH=CH (CH2) 2CH=CH (CH2) 2CH=CH (CH2) 4COOH.
Paper chromatography of phospholipid mixture was carried out with n-butanol, ethylenglycol, water (4 : 1 : 3) and resulted to separate into each constituent. With ascending method for 6 hours at 21°C the mixture of cardiolipin, lecithin and lysolecithin was separated into three spots and Rf values were 0.72±0.02 for cardiolipin, 0.85±0.03 for lecithin and 0.64±0.02 for lysolecithin. The mixture of phosphatidyl ethanolamine and phosphatidyl serine was also separated into two spots, and Rf values at 23°C were 0.80±0.02 for the former and 0.64±0.02 for the latter with same condition as described above. The increase of water content in the solvent system decreased the Rf values of phospholipids, indicating 0.92, 0.84, 0.72±0.02 for cardiolipin and 0.95, 0.90, 0.85±0.03 for lecithin, with solvent systems which were composed of butanol : ethylenglycol : water at the ratio of 4 : 1 : 1, 4 : 1 : 2 and 4 : 1 : 3 respectively.
Studies were made, under the optimum constant temperature of 37.5°C determined in Report No.3, on the effects of the hydrolytic action of the fatty matters in rice bran due to lipase by such physical factors as packing degree (apparent specific gravity) of rice bran, water content, irradiation of ultraviolet ray, freezing treatment, and size of rice bran particles. As a result, it was found that the greater the packing degree (apparent specific gravity) of rice bran the faster the hydrolytic velocity of the fatty matters by lipase, and that the lipase action is accelerated when the water content is approximately 20%. The hydrolysis velocity decreases when the water content is less than 20% or more than 20%. Irradiation of ultraviolet ray of a carbon arc lamp and sunlight upon rice bran had no effect on the lipase action. The hydrolytic velocity was the fastest when distilled water and various kinds of buffer solutions were added to rice bran, mixed by stirring and given a freezing treatment. Next fastest hydrolytic velocity was observed when the aforementioned aqueous solutions were added after giving a freezing treatment to raw rice bran. The hydrolytic velocity was the slowest when a freezing treatment was not given. It was also found that lipase action ceases at a temperature ranging from -16 to -18°C. In regard to particle size of rice bran, the smaller the particle size the faster the hydrolytic velocity by lipase. The hydrolytic velocity of pulverized rice bran is faster than that of unpulverized rice bran. It was found that the following index law exists between the residual percentage of rice bran sieving (R) and the acid value (x) of its fatty matters : R=100e-bxn in which b and n represent constants.
We studied about the melting point of cacao butter by treating with different temperature and gained the results as follows. 1. Different melting point of cacao butter was observed by the different cooling condition, and the melting point rose upward by the storage for long period. Only one day storage at 25°C gave melting point of 32°C or 33°C. 2. When the crystallized cacao butter was repeated, higher melting point than the untreated, was quickly attained. For instance, by the reheat treatment at 15°C for one hour or at 25°C for one hour gave melting point only 1°C lower than the highest melting point. Moreover as the another condition, by cooling at -50°C for one hour and then by reheating at 29°C for 5 hours, it showed the highest melting point, this was unchanged. From these evidences it was found that the maximum melting point is to be given quickly by reheating above 25°C. 3. It was convinced that a good result is to obtain by cooling and then reheating the bitter chocolate, or by adding 10% of stable crystalized cacao butter, and this was also proved through the graphical analysis of temperature gradient of cooling curve. 4. If tempering tangent of the cooling curve shows the value of near 1.0 or below 1.0, this molten chocolate is to be assumed that this was tempered under the good conditions, it was found.
Methyl linoleate was isomerized with iron pentacarbonyl catalyst. Solid fatty acids composed mainly of trans-trans conjugated dienoic acid were separated from the reaction product by low-temperature crystalization. Methyl esters of the solid fatty acids were oxidized in acetone by potassium permanganate. The oxidation products included the monobasic acids, caproic and heptanoic acids, and the dibasic acids, azelaic, sebasic, and oxalic acids. From the analysis of the oxidation products, it is considered that Δ9 : 10, 11 : 12 and Δ10 : 11, 12 : 13 octadecadienoic acids are present in the solid fatty acids separated from the product of isomerization of methyl linoleate with iron pentacarbonyl catalyst.
The present investigation was undertaken to discuss the accelerated deterioration of fried potato chips by the different rancidity of oils. The stability of these frying oils, non-rancid (N), slightly rancid (MR) and comparatively large rancid cotton seed oils (VR), were ranked as follows : N>MR>VR. The potato chips fried by these oils were stored at 15°C and 40°C for 30 days, while the respective accelerated deteriorations were periodically measured by means of peroxide value, carbonyl value and conjugated dienoic acid contents. The results are as follows, 1) N chips were very stable and showed a slight difference of deterioration at 15°C and 40°C. 2) As for the MR and VR chips, marked difference appeared between the storages at 15°C and 40°C, but similar deterioration tendencies have been observed and no significant difference appeared in the storages at the same temperature. Based on these results, it seems reasonable to assume that the deterioration of fried products are highly accelerated by the rancid oils regardless of their rancidity, and it is not desirable to add fresh oil to the frequetly used oil in a usual manner.