Muscle structure, proteins, and meat quality

Muscle is a major source of protein consumed by humans. With a more adequate food supply, meat quality and meat tenderness become increasingly important to meet the consumer's requirement. Meat tenderness is associated with many factors involving structural changes of muscle, protein degradation, breakdown of high-energy compounds, enzyme activity, pH, temperature, and processing time. It also varies between species and breed, different muscles, and at different distances from the muscle surface because of temperature gradients during the conversion of muscle to meat. This chapter summarizes skeletal muscle structure and contractile function, protein degradation, enzyme changes, and changes of muscle-associated connective tissues postmortem. Furthermore, examples that discuss their effects on meat tenderness have been given. Although advanced research and technologies have been applied to improve meat quality, some of the mechanisms involved in conversion of muscle to meat still remain to be determined.