Effect of freezing and salting on the activity of lipoxygenase of the muscle tissue and roe of Baltic herring

Abstract

Freezing followed by frozen storage of Baltic herring at -25°C for a period of 6 months resulted in lowering the activity of lipoxygenase of the muscle tissue down to 78.2% and of the roe down to 70.0%. The activity of the enzyme, extracted from the muscle tissue, stored in a buffer solution at -10, -18, and -25°C declined in reverse proportion to the increase of the storage temperature. Salting of herring, until they reached from 9.8 to 18.5% of salt content in their muscle tissue caused a decline in the activity of lipoxygenase, which was in direct proportion to the concentration of salt. Lipoxygenase of roe was catalysed more extensively during the weak salting (9.8% NaCl) than it was during medium- (12.3% NaCl) or strong salting (18.3% NaCl).