② Scale removal
1. International market for fresh or frozen skin-on fillets
2. A mechanical device for scale removal results in great losses and quality reduction
3. Enzymatic descaling methods
4. Three basic elements in enzymatic descaling
⑴ Mild acid treatment to loosen the mucus layer
⑵ Enzymatic degradation of the outer skin structure
⑶ Washing off scales and enzymes by water jets
③ Production of caviar and spermary extracts
1. Proteases - fish pepsins, collagenolytic enzymes from crab hepatopancreas
2. Enzymatic production of caviar from salmon and trout roe
3. 90% yield of caviar from roe of rainbow trout vs 70% with the conventional mechanical
4. Spermary extracts from fish milt and skipjack tuna
- More effective by the addition of enzymes from the skipjack Pyloric caecum