1. Postmortem changes in Fish

2. Changes in raw fresh fish
In rigor the fish body will be completely stiff changes in eating quality: Very fresh has a sweet, sea weedy and delicate taste.

3. Autolytic change Two types of fish spoilage: enzymatic and bacterial.
Respiration takes place in two stages: an anaerobic and an aerobic stage.

4. Cytoplasm Anaerobic Metabolism
Post mortem reduction in pH of fish muscle has an effect on the physical properties of the muscle.

5. Autolysis and nucleotide catabolism
The softening of the muscle during resolution of rigor (and eventually spoilage processes) is coincidental with the autolytic changes.

6. Degradation of ATP to hypoxanthine (Hx) and ribose
Very fresh fish, have low K-values.
Hypoxanthine impart a bitter flavour in spoiled fish.
IMP is responsible for the desirable fresh fish flavour