Soybean oil, after undergoing the refining, bleaching and deodorization, generally develops objectionable flavours and also tends to increase colour during storage. These phenomena, commonly termed “flavour reversion” and “colour reversion”, are very undesirable when soybean oil is used for preparing salad oil. Several methods have been known to improve the colour-stability of soybean oil. In this paper, effects of the deodorization temperature (240, 270 and 295°C) upon the colour reversion and other properties of soybean oil were studied with the following results. 1. Increase in deodorization temperature causes a progressive decrease in tocopherol content and a higher colour-stability of deodorized oil, but it is attended with a progressive lowering of iodine value. As the deodorization temperature becomes higher, the linoleic and linolenic acid content of deodorized oil decreases, while the conjugated diene content increases. 2. Increase in deodorization temperature lowers the A.O.M. stability of deodorized oil. The A.O.M. stability is, however, fairly improved by adding citric acid to the deodorized oil. 3. The formation of trans-acid becomes more marked as the deodorization temperature becomes higher.
The effect of dehydrating the rice bran before solvent extraction and its importance have been previously reported. In this paper this was reconfirmed by comparing the rice bran with corn germ which is a proper raw material for comparison. The maximum point of extraction velocity curve, remaining miscella in the extracted marc and drying and hygroscopic properties were discussed. In the case of corn germ : a) Area in the constant drying velocity curve and hygroscopic velocity are smaller than that of rice bran. b) Curve of solvent extraction velocity has a maximum at 3 percent moisture, and increase in the rate of extraction to raw material was small. It showed a large deviation in the figures obtained at the maximum drying and nearby conditions. c) Quantity of miscella remained in the extracted marc was less than one third of that of rice bran. Decrease in weight by drying was also less than the rice bran. From the above result, it was made clear that the rice bran has a characteristic difference from other materials, shown in the above (b) and (c) which come from the particle-size and the composition of rice bran in the solvent extraction process. Hot solvent extraction has more effect than the material-stirring extraction for rice bran. The differences in properties of extracted oil by different solvents were outstanding in color and color intensity, and other difference was little. The ratios of color intensity for trichlorethylene extracted oil : benzene ext. oil : pet. benzene ext. oil were 4 : 2 : 1. Freezing of pure benzene could be prevented by mixing 30 percent of pet. benzine, whereby the freezing point descend to -8°C, and this is confirmed by measuring specific gravity.
Rice bran which was directly sampled by an author from rice mills in Southeastern Asia, rice bran sent from several area as sample by importer, and domestic rice bran were compared as the raw material of oil about the qualities of bran and extracted oil to see the differences by the place of production and by the extracting conditions. As a result, the difference in oil content of rice bran produced in different place was due to the polishing method. Generally, the rice bran from Southeastern Asia contained 3% less moisture and 5% less oil than the domestic rice bran. Sap. value was a little higher, and iodine value was a little lower. The color was lighter than the domestic rice bran oil. U.S.M. % and mp showed minor difference. The minor components which have U.V. extinction maxima in the crude oil were not larger in difference by the place of production than by the conditions of extractions (the kind and the temperature of the solvents). U.S.M. was also equal in the quality of eliminating the absorption by conc. alcoholic pottash saponification. The boiled-rice bran had much oil content and low acid value, being suitable as the raw material for oil production. The grain size of bran is 420250 μ in diameter, being 1/2 of domestic rice bran.
The water number (W. N.) of polyoxyethylene derivatives of fatty alcohols and of polyoxypropylene cetyl ethers (general formula CPaEb:where C is cetyl alcohol, P propylene oxide, E ethylene oxide, and a and b are numbers of moles added, respectively) was measured and studied with relation to the properties of these derivatives. (1) Polyoxyethylene derivative of fatty alcohols : A tendency that the W.N. increases linearly with increase of the mole number of E was observed, but it gradually began to deviate from the linearity and became smaller through the maximum. When the mole number of E is above 100, it was observed a tendency that the W.N. converges to a range from 11 to 12. (2) CPaEb : (a) If CPa, polyoxypropylene cetyl ether, is assumed as an oleophilic group, the feature of increse in W.N. with increase in mole number of E was almost the same as in the case of usual nonionic surfactants. (b) Solubility of these derivatives against water could be clearly classified by the magnitude of W.N. (3) For the raw material to which the ethylene oxide was reacted, it was confirmed that the difference in W.N. corresponding to the increase in the carbon number by 24, from CP0 to CP8, are approximately equivalent to the difference in W.N. corresponding to the increase in carbon number of saturated fatty alcohols by 2 from C16 to C18.
In order to prepare samples for stability tests, hydrogenated fatty oils were treated with boiling diluted salfric acid solution then followed by washing, alkaline refining, activated earth bleaching, and deodorizing. Such refining was found to be satisfactory for the purpose of eliminating copper and other pro-oxydant metals. A routine test for evaluating stability was proposed, comprising of exposing refined and deodorized specimens under direct sun light or artificial ultra violet light and determining the order of their stability by organoleptic evaluation on the slightly reverted specimens. From the results of the experiments, it was found that hydrogenated tallow, lard, finback whale oil developed reversion flavor when their peroxide value were still well under 5 m. eq. /kg. Also an evaluation was made on stability of five hydrogenated finback whale oil having almost the same lodine number (68-69) prepared with Adkins, Cu-Cr (9 : 1), Cu-Al (3 : 2), Cu-Ni (9 : 1) and KW type catalysts.
It is observed that ampholytics are effective as antistatic agents and softeners, without effecting dyeing. To investigate the adaptability of ampholytics as oiling agent, the drawing friction of “Bonnel” fiber treated with it was measured. Minimum values of friction were observed at the concentrations between 0.030.16% for 1-oxyethyl-2-heptadecyl imidazolinium betaine, 0.070.1% for N-lauryl-N, N-dimethyl-α-betaine and 0.20.4% for oleic acid. For the oiling of “Bonnel”, much smaller quantities of ampholytics are required as compared with oleic acid.
Hays, Ball and their co-workers proposed the following equation for estimation of the content of abietic acid in disproportionated product. Abietic acid %=α241-α248.5/27.5×100 where;α241 and α248.5 are the specific adsorption coeffici-ents at 241 mμ and 248.5 mμ respectively. When disproportionation of tall rosin was carried out using active carbon catalyst only, experiments showed that the content of abietic acid from upper equation was influenced by the unsaponifiable matter. Because α241 of the unsaponifiable matter was much larger than α248.5, and the extinction coefficient of disproportionated product was increased as a whole by the unsaponifiable matter. But, in disproportionation with Pd-catalyst, the content of abietic acid was scarecely influenced by the unsaponifiable matter, because α241-α248.5 was very small. The saponifiable component, which is scarcely soluble in iso-octane was produced in a certain reaction condition of disproportionation. This component having the maximum extinction coefficient at 250 mμ makes larger the extinction coefficient of disproportionated product as a whole, but has influenced little on equation for estimation of content of abietic acid. The disproportionation of tall rosin with Pd-catalyst was investigated. The active carbon was the best as carrier and 1 part of Pd to about 100 parts of active carbon was suitable ratio. The more catalysts, the lower temperature or the shorter reaction time at the advancing reaction, the larger activity of the recovered catalysts were achieved. In the cyclic reuse of the recovered catalysts, the required amount of the catalysts was about 0.25 % (2 cycles with 0.5%) in the average. In the additional use of catalyst, mixed use of new additional catalyst with the recovered was more effective than that in which the recovered catalyst was used at first and then new catalyst was subsequently added. The requirement of the catalysts were about 0.13% and 0.2% in the average for the former system and the latter respectively.
Disproportionation of tall rosin with Pd-active carbon catalyst under hydrogen atomosphere was investigated. The required amounts of the catalyst in disproportionation under hydrogen atomosphere was one fifth of that in nitrogen, and the extinction coefficient of ultraviolet absorption spectra of the reaction product under hydrogen became smaller on the whole than that under nitrogen. As phenolic matter is said to lower the yield of polymer, estimation of phenolic matter was made with a result that only a trace of phenolic matter was found qualitatively. The reaction was not affected by the amount of hydrogen within the limit of conditions in experiment. The deterioration of activity of catalyst under hydrogen atomosphere was less than that of nitrogen, and therefore cyclic reuse of the catalyst was possible for five times. When 0.1% of recovered catalyst is used, 0.03% of new catalyst should be added for each cycle. In this case, the consumption of catalyst of each run would become nearly 0.03% at last. Wood and gum rosins were disproportionated easily compared with tall rosin.