Canning and Fish Packaging Technology

Unit 6 - Canning of commercially important fishes and shellfishes

6.2.2.1.Classification of tuna meat based on colour
Based on colour, tuna is designated as follows

• White : Tuna meat having Munsel value (MV) of 6.3 or more. Only albacore is having this designation.
• Light : Any tuna with meat not darker than M.V of more than 5.3 but less than 6.3.
• Dark : Any tuna darker than MV of 5.3 (less M.V than 5.3)

Any tuna having meat with M.V of less than 5.3 are not suitable for canning.

For tuna canning, both fresh and frozen material are used. There are several styles of canned tuna products. The different steps involved in canning of tuna is by and large same despite differences in variation in the size of the species, proportion of light and dark meat and the styles of liquid fillings.

After dressing the fish are semi dressed and precooked. Precooking is done at 100 to 105^oC and time may vary from 1-7 hr depending on the size of fish. During precooking the centre temperature should attain at least 71^oC. After precooking, it is cooled and partially dried in chilled atmosphere. Separation of light and dark meat is achieved manually and light meat is used as lions for packing into the cans.