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Muscle Biology & Meat Science B. A. Reiling Know how. Know now. - PowerPoint PPT Presentation

Know how. Know now. Muscle Biology & Meat Science B. A. Reiling Know how. Know now. What is Meat? Animal tissue suitable for human consumption Fresh Meats no mechanical treatments or added ingredients steaks, pork chops


  1. Know how. Know now. Muscle Biology & Meat Science B. A. Reiling

  2. Know how. Know now. What is Meat?  Animal tissue suitable for human consumption  Fresh Meats  no mechanical treatments or added ingredients • steaks, pork chops University of Nebraska – Lincoln

  3. Know how. Know now. Conversion of Muscle into Meat Series of postmortem chemical reactions & physical changes  Loss of blood  loss of O 2  loss of ATP  ATP = energy required for muscle movement  With loss of ATP  Rigor mortis  Buildup of lactic acid  pH  from ~ 7.0 to 5.4 in 24 h University of Nebraska – Lincoln

  4. Know how. Know now. With Anaerobic Metabolism, carbohydrates (glycogen) stored in muscle are broken Lactic ATP down for fuel, so muscle can Acid still contract post-mortem Lactic ATP CHO Acid for a limited time. CHO Lactic ATP  Also creates Acid CHO  “lactic acid” which causes the pH of muscle to drop from ~ 7.0 to 5.4 University of Nebraska – Lincoln

  5. Know how. Know now. Conversion of Muscle into Meat  Muscles are designed for 1 of 2 purposes  1) locomotion  2) support  The anatomy, physiology, and function of each muscle affects meat palatability.  Locomotive muscles  more tough  Support muscles  more tender University of Nebraska – Lincoln

  6. Know how. Know now. Palatability vs. Cost  Preferred retail cuts ...  Originate from the Rib & Loin (middle meats) • Muscles of support  TENDER; < connective tissue  Cost: $8 to $20 / lb  Less expensive cuts ...  Originate from the Chuck & Round (end meats) • Muscles of locomotion  TOUGH; > connective tissue - Exception = Flat Iron  Costs: $5 to $8 / lb University of Nebraska – Lincoln

  7. Know how. Know now. Physical Composition of Meat  Muscle  major component  Muscle fibers composed of proteins  Connective tissue  surrounds each muscle fiber and bundle  Fat  Bone University of Nebraska – Lincoln

  8. Sarcomere Smallest contractual unit of the muscle

  9. Know how. Know now. Slide adapted The Sarcomere from Ty Schmidt (UNL Meat Science) Comprised of overlapping protein filaments  Thick filament = Myosin protein (80%)  Thin filament – Actin protein (20%) University of Nebraska – Lincoln

  10. Know how. Know now. Sarcomere in state of rest Slide adapted from Ty Schmidt (UNL Meat Science) (uncontracted) University of Nebraska – Lincoln

  11. Know how. Know now. Slide adapted Sarcomere in contracted state from Ty Schmidt (UNL Meat Science) University of Nebraska – Lincoln

  12. Know how. Know now. Slide adapted Myosin Protein – Thick filament from Ty Schmidt (UNL Meat Science) ATP University of Nebraska – Lincoln

  13. Know how. Know now. Slide adapted Actin Protein – Thin filament from Ty Schmidt (UNL Meat Science) Myosin Binding Site University of Nebraska – Lincoln

  14. Know how. Know now. Slide adapted Sarcomere – Uncontracted from Ty Schmidt (UNL Meat Science) ATP Myosin Binding Site University of Nebraska – Lincoln

  15. Know how. Know now. Slide adapted Sarcomere – Contracted from Ty Schmidt (UNL Meat Science) Myosin Binding Site University of Nebraska – Lincoln

  16. Know how. Know now. Flank Steak Tenderization  Muscle fibers run in one direction  If cut “with the grain” • Intact, long muscle fibers  If cut “against the grain” • Many small pieces of fibers  Mechanical tenderization  Physical breakdown of muscle fiber cell walls University of Nebraska – Lincoln

  17. Know how. Know now. Flank Steak Tenderization  Chemical tenderization  Meat is acidic (pH = 5.4) • Lactic acid production during rigor mortis  Soy Sauce or Baking Soda is basic  Chemical reaction  breakdown of proteins  Enzymatic Breakdown – Papain  Breaks down the myosin protein University of Nebraska – Lincoln

  18. Know how. Know now. Effect of Cooking on Tenderness  For a TOUGH piece of meat, what cookery method should result in the most tender, cooked product? Why?  Hey, this could be an experiment! University of Nebraska – Lincoln

  19. Know how. Know now. Effect of Cooking on Tenderness  Dry Heat -- Broiling & Grilling  High temp, short time  tender cuts  Sear outside to “lock in” juice  Fiber & connective tissue breakdown • not an issue; originated from muscles of support  Moist Heat -- The “crock pot”  Low temp, long time  tough cuts • To an internal temp of ~180 o F  Heat & moisture break down connective tissue University of Nebraska – Lincoln

  20. Know how. Know now. Key Points: Muscle Biology  Muscle requires energy (ATP) to contract  During rigor mortis, muscle pH  to 5.4  Muscle = bundles of muscle fibers  Sarcomere is smallest contractile unit  Muscles of support vs. locomotion University of Nebraska – Lincoln

  21. Know how. Know now. Extension is a Division of the Institute of Agriculture and Natural Resources at the University of Nebraska – Lincoln cooperating with the Counties and the United States Department of Agriculture. The Youth Development program abides with the nondiscrimination policies of the University of Nebraska – Lincoln and the United States Department of Agriculture. University of Nebraska – Lincoln

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