Value added fish by-products - Nordic Innovation

effects on fish muscle, the gelatin was also added dry to fish mince (Pollachius virens) in
various concentrations (0, 0.5, 1.5 and 3.0% w/w), and frozen at -24°C for 1 week. The
parameters evaluated were drip loss, WHC, T2 transversal relaxation time and texture.
Both chemical and physical properties of the gelatins were considerable different. The melting
point is one of the major physical properties of gelatin gels. This is governed by molecular
weight, as well as by complex interactions determined by the amino acid composition and the
ratio of α/β-chains present in the gelatin (Karim & Bhat 2009). Differential scanning
calorimetry (DSC), heating (-10 to 40 °C) and cooling (40 to -10 °C) scans at 5 °C/min of
6.67% (w/v) gelatin solutions (CP and HMWD) were performed to observe the melting and
the gelling temperatures. Melting temperature was observed from the maximum of the
endothermic temperature peak and the gelling temperature was observed from the maximum
of the exothermic temperature peak in DSC thermogram. The melting and the gelling points
of these two gelatins were quite different, were CP showed significantly lower melting and
gelling points. These results indicate that CP would be more suitable as ingredient in fish
fillets.
The HMWD and CP showed completely different viscosity behaviour (Table 3.6). The
HMWD formed very strong gel at the concentration 6.67% (w/v), which entailed that
viscosity measurements were impossible at this concentration. Therefore, 3% HMWD
solution were prepared and the viscosity measured. The CP solutions showed different
behaviour. At the concentration of 6.67% (w/v) no viscosity was found. Increased gelatin
concentration (10 and 15% w/v) had no impact on the gel forming ability. Additional, the
effects of salt on the gel forming ability was investigated by adding salt to the fish gelatin
solutions (6.67% w/v) at the concentrations of 0, 1.5 and 3% salt. The salt had no affect on CP
where no gel was formed with or without salt. The salt, on the other hand, increased the gel
forming ability of HMWD.
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