Changes in myofibrillar proteins during processing of salted cod ( Gadus morhua) as determined by electrophoresis and differential scanning calorimetry

Abstract

The effects of salt-curing, drying and rehydration on muscle proteins in cod ( Gadus morhua) were studied during the processing of heavily salted cod or “bacalhau”. The aim was to observe conformational stability and possible degradation or denaturation, with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and differential scanning calorimetry (DSC). The salting process significantly decreased the heat stabilities of both myosin and actin. The decrease in water content during dry-salting did shift the transition temperatures slightly back to higher temperatures. The results, from the SDS-PAGE, showed that the myosin heavy chain (MHC) was cleaved into smaller sub fragments in the salting process with the two heavy meromyosin fractions (HMM S1 and S2) and the light meromyosin (LLM) fraction being the most abundant. Actin was less affected than myosin.