In the foregoing paper, the author reported that ethyl ester of highly unsaturated fatty acid freshly obtained from cuttle fish oil showed quite the same good nutritive effect as oleic acid ester for rat, while the acid exposed to air was proved to be extremely toxic.
Since it seems to be most plausible that the toxicity is concerned with the formation of peroxide by autoxidation of unsaturated fatty acid, the author determined the amount of peroxide. The result proved. this was just the case, the details of which will be reported here.
EXPERIMENTAL
The determination of peroxide was carried out following the Wheeler's method improved by Nakamura (1). It runs as follows.
An adequate portion of the sample, usually 0.1-0.5g., was exactly weighed out …show more content…
capacity, mixed with 20ml. of carbon tetrachloride, 30ml of glacial acetic acid and finally 1ml. of saturated potassium iodide solution. After well shaken for 1minute, 100ml. of distilled water was added to and thus free iodine liberated in the solution was titrated by 0.01N thiosulphate solution. 1 ml. of this. thiosulphate solution corresponds to 0.00008g. of oxygen.
The acid ester used here was prepared from cuttle fish oil as described in the fore going paper and had the foolowing properties.
About 50g. of this ester was poured into Petri-dish and submitted for autoxidation
* The resume of this experiments was reported at the 26th Annual Meeting of the Japanese Biochemical Society, in April, 1954.
647
TABLE I
648 N. MATSUO by contact with air at room temperature (2-18•K). The determinations of peroxide were carried out at a few days interval over 200days. The results are illustrated in
Fig. 1.
FIG. 1. The change of peroxide (I) and iodine values (II) of the fatty acid ester exposed to air at room temperature
Since it seems to be most plausible that the toxicity is concerned with the formation of peroxide by autoxidation of unsaturated fatty acid, the author determined the amount of peroxide. The result proved. this was just the case, the details of which will be reported here.
EXPERIMENTAL
The determination of peroxide was carried out following the Wheeler's method improved by Nakamura (1). It runs as follows.
An adequate portion of the sample, usually 0.1-0.5g., was exactly weighed out …show more content…
capacity, mixed with 20ml. of carbon tetrachloride, 30ml of glacial acetic acid and finally 1ml. of saturated potassium iodide solution. After well shaken for 1minute, 100ml. of distilled water was added to and thus free iodine liberated in the solution was titrated by 0.01N thiosulphate solution. 1 ml. of this. thiosulphate solution corresponds to 0.00008g. of oxygen.
The acid ester used here was prepared from cuttle fish oil as described in the fore going paper and had the foolowing properties.
About 50g. of this ester was poured into Petri-dish and submitted for autoxidation
* The resume of this experiments was reported at the 26th Annual Meeting of the Japanese Biochemical Society, in April, 1954.
647
TABLE I
648 N. MATSUO by contact with air at room temperature (2-18•K). The determinations of peroxide were carried out at a few days interval over 200days. The results are illustrated in
Fig. 1.
FIG. 1. The change of peroxide (I) and iodine values (II) of the fatty acid ester exposed to air at room temperature