Formation of malonaldehyde in frozen baltic herring and its influence on the changes in proteins.

The relationship between the malonaldehyde formed as oxidation product of lipids, and changes of proteins in frozen Baltic herring (Clupea harengus var. membranus) was studied. Changes occurred in the muscle proteins due to freezing, so that water-binding capacity, solubility, and the amount of free epsilon-amino groups in these proteins decreased. A close relationship was found between the amount of malonaldehyde and changes of proteins in the different phases of storage. The reaction of malonaldehyde with the free amino groups of the proteins may be one of the factors on which the changes of proteins during frozen storage are based.