OXIDATIVE STABILITY OF FROZEN LIGHT AND DARK MUSCLES OF SAITHE (POLLACHIUS-VIRENS L.)

Saithe, a lean gadoid fish, was processed and stored at -10C, -20C and -30C normal skinless fillets and as deep-skinned fillets. Properties related to lipid oxidation in the dark and light muscle tissues and in the two types of fillets were investigated after 6 to 9 months of sto rage. The lipid content and fatty acid profiles indicated the presence of relatively large amounts of triacylglycerols in the dark muscle. P rolonged storage at -10C and -20C resulted in a decrease in the conten t of n-3 polyunsaturated fatty acids (n-3 PUFA) in the dark muscle tis sue. At the highest temperature, a reduction in n-3 PUFA is also indic ated in the light muscle. Lipid oxidation as measured by 2-thiobarbitu ric acid reactive substances (TBARS) and reduction in alpha-tocopherol , was most pronounced in rite dark muscle. Evaluation of fillets by se nsory analyses and TBARS values demostrated that industrial deep-skinn ing improves cold storage stability of saithe fillets.