Structure, Composition, Nutritive Value and Biochemistry of Post-Mortem Muscle

The transformation of muscle tissue into meat involves a complex series of biochemical and physical changes, transitioning from a metabolically active and flexible state to one that is mostly inert and rigid. This process, vital for food production, is heavily influenced by post-mortem metabolism, which significantly affects the properties and culinary suitability of meat. This chapter offers a thorough examination of the structural components, composition, nutritional value, and underlying biochemistry of post-mortem muscle. It begins by detailing the organization and functionality of muscle cells, with a particular focus on the role of myofibrils and sarcomeres in facilitating movement and maintaining structural integrity. The chapter emphasizes the key metabolic pathways oxidative and glycolytic that drive energy production in living organisms, highlighting their importance in the post-mortem context, especially regarding lactate accumulation and its impact on muscle pH and quality. Additionally, the chapter explores the dynamic interplay between enzymatic and proteolytic processes, such as those involving the protease μ-calpain, and their effects on muscle texture and tenderness. Special attention is given to the variability in post-mortem proteolysis across different muscle types, reflecting their diverse fiber composition and metabolic properties. By thoroughly examining these aspects, the chapter provides valuable insights into the complex journey from muscle to meat, illuminating the factors that shape meat quality and consumer experience.