Value added fish by-products - Nordic Innovation

Figure 3.18. Total yield 21 after cooking after 1 month of frozen storage. (FPI=fillets injected with fish protein isolate;
FPH=fillets injected with fish protein hydrolyse (MariPep C)).
The water holding capacity (WHC) and transversal relaxation time (T2) of fresh cod fillets,
untreated (control) or injected with protein solution (hydrolysate or isolate), were also
analysed. The T2 transversal times can indicate the mobility and the location of water within
the fish muscle. T21 indicates intracellular fluid (water bound by large molecules such as
proteins); T22 on the other hand indicates extracellular fluid (water which is easily lost by
drip).
The highest WHC was measured in fillets injected with hydrolysates, the lowest in fillets
injected with isolate. Fillets injected with hydrolysate had higher T21 and lower T22 compared
to untreated fillets. This indicates that the water in the hydrolysate treated fillets is more
firmly bound than in untreated fillets. This is in agreement with the WHC results. Results on
fillets injected with isolate showed different behaviour. WHC was lowest in these fillets.
However, T21 was similar as in untreated fillets but T22 lower. This indicates that the bound
water is similar, but the free water is lower in the isolate treated fillets - these were less prone
to lose water which does not comply with the WHC results.
21 Evaluation of total yield was determined by multiplying the yield after storage (chilling, freezing (thawing))
and the cooking yield.
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