1. Week: 8

3. Fishmeal and fishoil production plant

4. Fishmeal and fishoil

5. Airdried

6. On the market

7. Quality changes
during preservation

8. Protein mink digestibility, in vivo tests
Heated
Protein mink digestibility, in vivo tests
Fishmeal
A matter of time and temperature
Drying temperature, °C
Mink digestibility, %
100 88 70 91
70 (5 seconds) 94

9. Heated
Lipids
more or less unaffected
if proper manufactured
Otherwise risc of rancidity

10. Cool / freeze
Prolonged shelflife

11. Other preservation methods
Proteins
Lipids
Salted
No effects
Might rancid
Smoked
Airdried
Might deterioate
Rancid
Fermented
Proteins → peptides ≈ bitter taste
Might get rancid

12. Vitamins in fish A 50 - 5.000 I.U./g D 0 - 1.000 I.U./g
Pantothenic μg/g
During heat processing
the vitamins will be destroyed
Depending upon the temperature

13. SUMMARY Fishes are cold blooded vertebrates.
Fish muscle is biochemically similar to mammals.
Fish proteins breakdown more rapidly than mammals.
Fish muscle have certain associated problems like
endogenous enzymes, free amino acids and small peptides etc.
Lipids from fish contain high levels of polyunsaturated fatty acids.
The stability of fish lipids is short due to their
polyunsaturated nature.

14. SUMMARY Most spoilage of fish is due to bacterial breakdown.
One spoilage characteristic found in fish and not in muscle foods
is trimethylamine formation. This odoriferous amine is responsible for the fish smell associated
with spoiling fish.
fish meat has high level of polyunsaturated fatty acids,
which are unstable.
Chilling of fish immediately after harvest is very important
part of preservation.