Canning and Fish Packaging Technology

Unit 6 - Canning of commercially important fishes and shellfishes

6.2.3.1.Canning of Shrimp
Among crustaceans, canning of shrimps is more widely practiced commercially. Removal of exoskeleton of shrimps is referred as peeling. This is done manually. The removal of internal organs(gastrointestinal tract, reproductive organs and hepatopancreas) is termed as deveining. After peeling and deveining, shrimps are blanched in 6% brine for 6 mins in boiling brine. Salt concentration and blanching time depends on the size of shrimp and variety. Blanching is done to get

• Proper curing (salt absorption)
• Required pink colour
• Good texture and flavour
• Reduced moisture content
• To maintain no loss or no gain in moisture content even after heat processing/to control drained weight.

After blanching, shrimps are packed in desired can size and then filled with media like oil or brine . Sometimes natural packs are also commonly practiced. Vacuum exhausting, seaming and retorting are the unit operations followed to complete the process.

Problem specific to canned shrimp

• Retort burn in dry pack – use parchment lining is followed to overcome then same.
• Sulphide blackening – Black spots appear inside can which is not acceptable. Sulphide blackening can be avoided by use of fresh raw material, use parchment paper especially at the side seam and use citric acid in brine.