Fish muscle and how it works

    The muscle of a fish is the organ used for locomotion. This part is divided into segmented blocks which contain two proteins, actin and myosin. Both are separated by connective tissue and their movement on each other helps the fish to move. The connective tissue runs from the muscle block around the fibre and are attached to bones and cartillage of the fish, this control the manner of swimming.

What happens to the fish muscle after death?
Fish requires ATP gotten from food for their energy requirement. After death, energy supply stops and enzymes start to attack the muscle leading to discolouration, off-flavour due to oxidation of enzymes, easy breakage etc.

"Rigor mortis" what is it about?
This is the stiffening of fish muscle brought about by post mortem biochemical processes. As soon as fish dies, the muscles are limp and can easily be flexed. The fish is said to be in pre-rigor and of excellent quality, such muscle can contract if stimulated by an electric shock. Fish is said to be in rigor when the muscles start to harden and become stiff and cannot contract if stimulated.

What are the factors that determine extent of rigor?
1) Freshness of the fish: The fresher the better
2) Nature of the flesh
3) Nutritional state of fish: The higher the glycogen content, the higher the lactic acid(acidity) content which is corresponding to extent of rigor.
4) Method of catch: Use of passive gear should be avoided
5) Degree of handling: Fishes should be handled properly

How does temperature affect rigor?
Microbial activities is readily minimized by reducing or increasing the temperature to a level that is non favourable for their survival. Temperature below 0 degrees and above 85 degrees will stop almost all microbial activity in fish muscle after death thereby increasing the extent of rigor.

How does pH affect rigor?
At lower pH i.e high acidity, extent of rigor is prolonged. As glycogen content breaks down to lactic acid there will be reduction in pH i.e increase in acidity.

How does salt affect rigor?
Many bacteria needs water to function and as salt is hypertonic it draws out water from the cell wall of  bacteria. This leads to dehydration in its cell wall leading to prolonged rigor in fish muscle.
Take note of all this for better fish product!!!!
ITS YOUR BOY TOLUBEST2015