Lipid changes in frozen stored fillets from pre- and postspawned hake (Merluccius hubbsi Marini)

The lipid composition of frozen stored fillets from pre- and postspawned hake was studied. The total lipid (TL) content in the chloroform/methanol extract from unfrozen postspawned hake was four times higher than that of prespawned fish. After freezing, the TL content of postspawning hake muscle remained unchanged whereas the TL extracted from prespawning fish muscle increased about 90%. The TL extractability of muscle from fish in both different gonadal conditions was not affected by frozen storage. Lipolysis in frozen stored fillets from prespawned hake occurs principally by hydrolytic action on phospholipids (PL), and phosphatidylcholine was the main PL hydrolyzed. Triacylglycerols were the main substrates hydrolyzed in frozen stored fillets from postspawned hake. Freezing and frozen storage affected polyenoics and n-3 fatty acids (FA). The decrease in the contents of n-3 FA in fillets from postspawned hake was lower than that observed in fillets from prespawned fish.