水産動物内臓油利用に関する研究-III

分子蒸留法によるビタミン油濃縮の工業化研究(その1)

抄録

In industrial practice of molecular distillation of vitamin oil it is generally very hard to expect the operation to be carried out with constant efficiency since the vitamin A as the object matter is often subject to great fluctuation in regard to magnification of concentration, yield and etc. As reported in this paper, the author conducted researches hence into some factors to be regarded as main causes of the above-mentioned fluctuation and tried to obtain fundamental knowledges necessary for carrying out industrial molecular distillation of vitamin oil with constant efficiency.
In the first place, method of pre-refining the vitamin oil to be subjected to distillation being examined, the results shown in Tables 1, 2 and 3 were obtained. These results indicate that the effect of pre-refining reflected in the results in subsequent distillation varies not only with the kind of pre-refining method but also with that of raw vitamin oil subjected to pre-refining as follows: In the case of liver oil of pollack, three methods here examined stand in respect of refining effect in the order of alkali-refining > washing with water > treatment with diatomaceous earth. In pre-refining liver oil of dogfish, three methods applied thereto, namely, alkali-refining, washing with water and treatment with active charcoal, are not greatly different from one another, leading equally to rather good results. In the case of whale liver oil, with which the effect of combination of alkali-refining with subsequent washing with water was examined, there can be got ready for the better result in molecular distillation by the more frequent washing with water, an especially good result being obtained when the oil is treated first with alkali and then with aqueous citric acid.
As to the color of the oil fraction remaining after the end of molecular distillation, it may be expected from the data in Tables 1 and 2 that a great improvement can be realized by pre-refining the raw oil with active charcoal.
In the second place, the phenomenon of sludge formation which causes the distiller to become undesirably stained was observed by carrying out molecular distillation experiments in a semi-micro pot still, the results shown in Table 4 and Fig. 3 being obtained. As seen from these results, sludge formation of vitamin oil begins at a temperature of 260-280°C and becomes remarkable at 300°C. Among the samples here examined, tuna liver oil was most liable to produce a serious amount of sludge and pollack liver oil came next, while liver oil of dogfish went into sludge only in a small proportion.
In the third place, the so-called out-gas, namely, gaseous decomposition products given rise to as vitamin oil is subjected to molecular distillation at an elevated temperature was examined of its amount of evolution by the help of the displacement curve 2 shown in Fig. 2. As seen from the results given in Table 5, the amount of out-gas evolved in the working stage of the 1st degassing was very large irrespective of the kind of animal from which the sample oil was obtained, every 1kg oil specimen giving off the out-gas amounting to 1, 500lmmHg under a vacuum of 2mmHg and 2, 400lmmHg under that of 3mmHg. Amount of out-gas was appreciably reduced, however, in the working stage corresponding to the 2nd degassing, the amount dropping to about 170lmmHg and about 80lmmHg with whale liver oil and with fish liver oils, respectively. Evolution of out-gas can prevail also in the working stage of distillation proper as seen from the result that the amounts of out-gas evolved in one run of feeding the distiller with vitamin oil were not less than 337-265lmmHg, 280-235lmmHg and 235-155lmmHg in the cases of liver oils of whale, “yoshikirizame” (Prionace glauca) and cod or dogfish, respectively.