The fact that the composition of the sarcoplasmic protein fraction changes when the
organelles are broken was suggested as a method for differentiating fresh from frozen
fish, under the assumption that the organelles were intact until freezing (Rehbein et al.,
1978, Rehbein, 1979, Salfi et al., 1985). However, it was later stated that these methods
should be used with great caution, as some of the enzymes are liberated from the
organelles also during iced storage of fish (Rehbein, 1992).