Development of an enzymatic method to differentiate fresh and sea-frozen and thawed fish fillets. I. Comparison of the applicability of some enzymes of fish muscle.

The activities of mitochrondrial and lysosomal enzymes in press juices of fresh and frozen and thawed fillets were compared. It was demonstrated that several lysosomal enzymes are suitable for the detection of thawed fillets, because their activities in press juice increased considerably in consequence of freezing and thawing fish fillets.