Kinetics of heat denaturation of proteins from farmed Atlantic cod (Gadus morhua)

Protein denaturation is considered to be the main reason for both water loss and textural changes in fish during thermal processing. Denaturation of proteins in muscle of farmed Atlantic cod was studied by differential scanning calorimetry. The denaturation of the proteins was compared to cook loss and loss in water holding capacity and it was shown that the protein denaturation occurs in a lower temperature range (35–66 °C) than the appearance of major cook loss (above 80 °C) when cod muscle is heated. Other mechanisms for release of water than protein denaturation should therefore be investigated.Kinetic parameters for changes in denaturation enthalpy of cod protein were estimated in the temperature range of 58–68 °C, corresponding to the denaturation of actin. The time-dependent decrease in denaturation enthalpy corresponded to a first-order mechanism. The decimal reduction time D62 °C was estimated to be 130.1 ± 5.4 min and the z-value 5.74 ± 0.11 °C.