INDUSTRIAL AND ENGINEERING CHEMISTRY
December, 1942
1489
FIGURE 3. PEROXIDATION OF FISHLXVER OILS
140
A , soup-fin shark (A); B , soup-fin shark (B); C. halibut; D , blue-fin tuna 420
peroxide formation, the rate of vitamin A destruction i s greatest. The percentage of vitamin A destroyed in t h e fish liver oils possessing no induction period on exposure to air a t 34.5” C. is directly proportional to the time; however, this relation holds true only when less than about 60 to 70 per cent of the vitamin A is oxidized. The curves in Figure 2, A and D,for the samples of tuna and shark liver oils treated with 5 per cent or less carbon show that, in the early stages of oxidation, the rate of vitamin A destruction is slower for a time than in the respective crude oils. This behavior can be explained by graphs A , B, and D of Figure 3, which show that the rate of peroxide formation in the initial stages of oxidation of the oils treated with 5 per cent or less of carbon is also slightly slower than for the crude oils. This again is probably due to the removal of pro-oxidants from the oils, although sufficient antioxidants remain to play a definite role.
f00
Bo
60
40
20
f40
Rate of Peroxide Formation
120
The oils treated with carbon in all instances (Figure 3) showed a shortened induction period and an ultimately faster rate of oxidation. The increase in peroxide content of the oils exhibiting no induction period is directly proportional to the time of exposure. The absence of an induction period in certain of the treated oils indicates that carbon has depleted the antioxidant content. From the above results it is evident that the antioxidant content of fish liver oils plays a major role in the resistance of these oils to atmospheric oxidation, apart from other effects due to the nature of the fatty acids present and the degree of unsaturation of the glycerides. Lowered resistance to oxidation, as measured by increased susceptibility to peroxidation, in turn governs to a major degree the rate of vitamin A destruction in fish liver oils.
IO0
&! % 80 2
3
60
lu
8&
40
20
Literature Cited
-
M
w
m
ORfGfuwL 5 %
fox
20 %
-
(1) Brookleaby, H.N.,Progress Repts. Pacific Biol. Sta., No. 44,4 (1940). (2) Ciusa, W.,Ann. chim. applicata, 30,141-6 (1940). (3) Denstedt, 0. F., and Brocklesby, H. N., J. Biol. Board Can., I ( 6 ) ,487-96 (1936). (4) Hassler, J. W., and Hagberg, R. A., Oil & Soap, 15, 115-20 (1938). ( 5 ) Hilditoh, T. P., “Chemical Constitution of Natural Fats”, p. 301 (1940). (6) Mattill, H.A,, and Crawford, B., IND. ENO.CHEY., 22, 341-4 (1930). (7) Simona, E.J., Buxton, L. 0..and Colman, H. B., Ibkd., 52, 706-8 (1940). PRESENTED before a joint session of the Divisions of Biologiml Chemistry and of Agrioultural and Food Chemistry at the 104th Meeting 08 the AMERICAN CHEMICAL SOCIETY, Buffalo, N. Y.
Nitroparaffins and Derivatives as Heat Sensitizers for Rubber Latices- Correction
0
/oo
200
HOURS A T 34.5”C.
300
In this article IIND. ENG. CHEM.,34, 1106 (1942)l cerium oxide was incorrectly designated in We tabulation of compounds that produced no gelling, Group IV. It should have been written CeOa. ARTHURWILLIAM CAMPBELL
