DETERIORATIVE CHANGES 361 



tion, salting, or irradiation, then the oxidation proceeds at a rate which 

 would normally be expected and the oil may become extremely rancid. 



When fish is stored at sub-freezing temperatures, the oil slowly oxidizes 

 and becomes rancid. Under such circumstances the development of ran- 

 cidity does not follow a typical induction type of curve but rather usually 

 occurs as a more or less straight line relationship between time and degree 

 of oxidation of the oil. 



The oil in the areas of the fish known as the dark meat such as occurs, 

 for example, along the lateral line and at other portions of the fish, oxidizes 

 at far greater rates than occurs in the light meat portions of the fish^ 

 This difference in oxidation rate in the dark and light meat portions of 

 the fish, which may be as much as 100 fold, is due to the presence in the 

 dark layer of fish muscle of haematin compounds which act as powerful 

 prooxidants. 



Antioxidants added to fish to be frozen usually add considerably less 

 protection against oxidation than would be predicted from model system 

 experiments employing either the pure oil or suspensions of the oil with 

 other fish tissue components. This disappointingly small effectiveness of 

 antioxidants to retard rancidity development in frozen fish is in part due 

 to difficulty in getting adequate penetration of the antioxidant to reach 

 and protect the oil in the tissue. Other factors must also be involved 

 such as differences between component substances and arrangements of 

 the substances at a cellular or histological level in the fish tissue as com- 

 pared to model systems of a relatively simple type where the antioxidants 

 function much more effectively. 



LITERATURE CITED 



1. Banks, A., Torry Research Station, Aberdeen, Scotland, Personal Communication. 



2. Brown, W. D., Venolia, A. W., Tappel, A. L., Olcott, H. S., and Stansby, M. E., 



Com. Fisheries Rev., 19, No. 5a, 27(1957). 



3. Burt, J. R., and Jones, N. R., J. Sci. Food Agr., 12, 344(1961). 



4. Farmer, E. H,, and Sutton, D. A., /. Chem. Soc, 1943, 119(1943). 



5. Hess, E., Contribs. Can. Biol, and Fisheries, 8, 491(1934). 



6. Jones, N. R., Biochem. J. 58, XLVII (1954). 



7. Love, R. M., /. Sci. Food Agr., 12, 439(1961). 



8. Olcott, H. S., J. Am. Oil Chemists' Soc, 35, 597(1958). 



9. Olcott, H. S., and Einset, E., /. Am. Oil Chemists' Soc, 35, 159(1958). 



10. Olcott, H. S., and Kuta, E. J., Nature 183, 1812(1959). 



11. Rhodes, D. N., Low Temperature Research Station, Cambridge, England, 



Personal Communication. 



12. Swern, Daniel, Chap. 1, pp. 8-21 in "Autoxidation and Antioxidants," W. O. 



Lundberg, ed., New York, Interscience Publishers, 1961. 



