Myofibrillar protein degradation of carp (Labeo rohita (Hamilton)) muscle after post‐mortem unfrozen and frozen storage

Abstract

The degradation of myo®brillar proteins of rohu carp (Labeo rohita (Hamilton)) muscle was analysed after post-mortem storage. Muscle ®llets were kept either unfrozen at 2°C for up to 15 days or frozen at À8°C or À20°C for up to 6 months. A co-ordinated histochemical, biochemical and electrophoretic study showed a differential response of the carp muscle, revealing clear degenerative/ degradative changes speci®c to the post-mortem storage temperatures. The myo®brillar protein fractions, namely myosin light chains and a-actinin, showed degradative changes during the above storage conditions, whereas other protein fractions in the high-molecular-weight range fragmented to give lower-molecular-weight proteins. The importance of the post-mortem storage temperature for controlling the degradation of the myo®brillar proteins was emphasised. This is the ®rst report on this popular ®sh species, known for its culinary importance, showing that speci®c protein fractions of the myo®brils degrade during post-mortem storage.

Determination of Potential Health Hazards and Nutritional Attributes of the Fresh and Smoked Freshwater Thin-Lipped Grey Mullet (Liza Ramada)

“…This indicates the initiation protein degradation. A pronounced degradation was noticed with storage time leading to the disappearance of bands (3) and (6) probably due to enzymatic proteolysis of the myofibrillar proteins causing structure disruption and postmortem softening as reported in other studies [71]. This finding supports the explanation related to biogenic amines increase following 30 days of storage.…”

Protein Changes Caused by High Hydrostatic Pressure (HHP): A Study Using Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared (FTIR) Spectroscopy

“…Prerigor muscle showed higher a-helix and lower b-sheet structures than postrigor muscle, while the antiparallel b-sheet structure (1,686 cm -1 ) was not affected by the rigor state. These results suggest that the a-helix reduction is affected by proteolytic degradation processes as in Jasra et al [19], who reported for carp that there was rapid degradation in the myosin light chains and low molecular weight compounds, such as a-actinin, which only have a-helix structures.…”

2D DIGE/MS to investigate the impact of slaughtering techniques on postmortem integrity of fish filet proteins

“…As such, the degradation process might take longer to complete, both due to the protein dimensions and to its release from the supramolecular contractile structure. Long-term degradation of Mhc has been reported by other authors; they observed that Mhc is fairly stable when fish muscle is stored in ice for a prolonged period [20,27,28]. This longer degradation kinetics may make it possible to detect a residual effect of the slaughtering technique even after 5 days of storage in refrigerated conditions.…”