Meat Science

INTRODUCTION

• Meat is the post-rigor aspect of muscle and the conversion of 'Muscle' to 'Meat' is the result of series of biochemical and biophysical changes initiated in muscle at the death of the animal due to stoppage of the blood circulation.
• There is immediate loss of oxygen supply to the muscle due to exsanguination (bleeding).
• As the Oxidation reduction potential is reduced, there is inhibition of aerobic pathway through TCA cycle as well as cytochrome system.
• The store of creatinine phosphate (CP) used for rephosphorylation of ADP to ATP (creatine phosphate + ADP = ATP + creatine) gets soon exhausted.
• Energy metabolism is then shifted to anaerobic pathway resulting in the breakdown of glycogen to lactic acid.
• This process continues till all the glycogen stored in the muscle is exhausted or the ultimate pH is reached.
• This resynthesis of ATP by anaerobic pathway is not enough to maintain the required ATP level and as it depletes, there is formation of actomyosin resulting in the onset of rigor mortis.
• The important changes that take place during postmortem period are follows :

  • Loss of Homeostasis
  • Postmortem glycolysis and pH decline
  • Rigor Mortis
  • Loss of Protection from Invading Microorganisms
  • Degradation due to Proteolytic Enzymes
  • Loss of Structural Integrity
• Thus the conversion of muscle to meat is a  series of the above biochemical changes  ultimately culminating in the resolution of rigor mortis.