Factors affecting the quality of a meat

Pre-mortem Factors:
The breed of the animal
The feed given to it
The way it has got rest
Slaughtering method

Post mortem factors:
Rigor mortis
Aeging
Tenderisation methods applied
Cuts and grades of the meat
Rigor mortis: By the interrupted metabolism in the cells, the carcass
stiffens which is termed as rigor mortis.(24-48 hrs in beef). After
slaughter, due to deficiency of oxygen, the cells undergo anaerobic
glycolysis and wastes (lactic acid) accumulate in the muscle which
lowers the pH of the meat and ATP concentration is also lost in 24
hrs. Permanent links are formed between Actin and Myosin and rigor
mortis occurs. It does not affect the nutritional quality of meat.
Aeging: Ageing is the resolution of rigor. The denaturation of the
muscle by the intracellular proteolytic enzymes; cathepsins tenderize
the meat. Aeging is carried out in cold room with temperature 0.5-20°C
for 1-4 weeks. The best flavor is developed in 2-4 weeks under
controlled humidity and wrapping.
Tenderising: It is the reduction in the number and strength of cross
linkage between the peptide chains and collagen. A meat is tenderized
by exercise, cold room storage, pounding, cutting, grinding and
vibrations. Enzymes like papain from papaya, bromelain from pineapple
catalyse the protein hydrolysis which tenderizes the meat. For best
tenderness, papain is injected in the animal 10 mins before the
slaughter. Papain becomes inactive 55°C. Using the low level salts
like NaCl, NaHCO3 increases the water holding capacity of the cells
which solubilises the proteins.
Curing: Curing is the preservation of meat by salting, drying. Curing
imparts unique flavor, red color and tenderness. Common salt, Sodium
Nitrate/Nitrite, sugar and spices can be used for curing. Nitrites fix
the red color and inhibit the clostridium. Sugar stabiles the color
and counteracts the saltiness. As per Codex alimentarius 150-500 mg of
nitrates can be used per Kg of meat.
Cuts and grades: A carcass is graded based on the proportion of fat
muscle and bone composition, the maturity of the flesh and marbling
(distribution of fat). A poor meat is darker, fibrous with coarse
grains, heavy fat layers and strong flavor.