抄録
In view of the recent remarkable progress in synthetic manufacturing of vitamin A, it is urgently needed to study procedures for extracting from fish liver oil pure vitamin A or vitamin A concentrate which is as much odourless and tasteless as possible. Because it is felt that the time will not be long before the fish liver oil produced in Japan losses its oversea market, unless such a study as stated above brings forth a successful result applicable to the industrial scale. However, few efforts have been paid in this direction here in this country since TAKAHASHI reported his methods for vitamin A extraction in 1925. Having closely examined two of TAKAHASHI's methods (B and C), we came to the conclusion that they are to much defective to be used for preparing from fish liver oil vitamin A concentrate which is comparable with synthetic vitamin A in quality as well as in cost.
In TAKAHASHI's method B, vitamin A in the saponified solution is to be concentrated when a large part of fatty acids is separated as alkali soap after adding aceton to the alcoholic solution; in the method C, fatty acids are separated as insoluble soap by adding metalic salts such as Ca, Ba, or Sr to concetrate vitamin A into organic solvent such as alcohol.
The results obtained from the experiments are as follows.
a) In TAKAHASHI's method B, extraction of vitamin A is almost completely performed, but soap of highly unsaturated acids can not be separated. Consequently, vitamin A thus extracted is lower in the rate of concentration than that of usual ether extraction (table 2).
b) The recovery rate of vitamin A in the method C is not so perfect as that in the method B, and the mixed soap is greater in amount than in the ether extraction (table 3, 4 and figure 1).
c) Precipitated calcium soap in the method C has contained a considerable amount of vitamin A. The fact seems to suggest that vitamin A may not be extracted as throughly as one intends, even if the extraction is performed after boiling the soap with alcohol. Moreover, vita-min A potency in the extract by this treatment is lower than that of the first extract (table 5).
d) Method C using methanol, ethanol or benzene-methanol mixture is also examined. Vitamin A recovery by this method is lower than that of usual ether extraction (table 6).
