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Meats

Meats. Chapter 6. Meat. Meat is the muscle of animals It is composed of muscle fibers, connective tissue and fatty tissue Beef – 15-30 months of age Veal 3 weeks to 3 months Lamb <14 months Mutton >14 months Pork 7-15 months of age. Meat Composition. Structure Water Muscle

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Meats

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  1. Meats Chapter 6

  2. Meat • Meat is the muscle of animals It is composed of muscle fibers, connective tissue and fatty tissue • Beef – 15-30 months of age • Veal 3 weeks to 3 months • Lamb <14 months • Mutton >14 months • Pork 7-15 months of age

  3. Meat Composition Structure • Water • Muscle • Connective Tissue • Adipose -Fatty- Tissue • Bone • Proportions of Each Varies According to Animal & Anatomy

  4. Composition of lean muscle tissues

  5. Meat composition Antibiotics & Hormones • Antibiotics Shield Animal from Disease Promote Growth Affect on Medicinal Antibiotics • Hormones Not Allowed by All Countries USDA Allows Hormones in • Cattle & Sheep • But Not Swine or Poultry

  6. Beef is obtained from • Steers - males castrated when they are young • Heifers - female before breeding • Cows - female after breeding • Bulls - adult males • Stags - males castrated after maturity • Calves - 3-8 months • Baby beef - 8-12 months • Veal - 3 weeks -3 months

  7. Pork is obtained from • Pigs <4monts of age, <120lbs • Hogs >4 months, >120 lbs • Swine 5-7 months • Gilts – females 5-7 months, before breeding • Barrows – males castrated when young • Sows – adult females that have litter • Boar – adult males

  8. Muscle tissue • Collection of muscle cells also called muscle fibers. Each muscle fiber is surrounded by a membrane called sarcolemna. • About 80 % of muscle fiber volume is made up myofibrils (i.e. 2000 thread like fibers which are the contractile elements of the muscle fiber. • Each myofibril consist of repeating contractile units known as sarcomeres bound to each other by Z discs. Each sarcomer is made of thick (myosin) and thin (four stranded rope made of actin, tropomyosin and troponin) filaments. • Muscle contraction occurs when thick and thin filaments slide past each other forming actinomyosin. • The energy for contraction is provided by adenosine tripolyphos- phate (ATP) • The remaining volume is filled up with sarcoplasm-enzymes, nuclei, mitochondria, glycogen granules etc

  9. Connective tissue • Forms the walls of the muscle fibers, bounds the muscle fibers into bundles, surrounds the muscle as a membrane, makes up tendoms and ligaments that attach muscle to bones. • Responsible for a toughness of cooked meat. • Composed of amorphous mixture of mucopolysaccha-rides and proteins • There are three types of connective proteins: collagen, reticulin (similar to collagen-consider to be a precursor of collagen), elastin (blood vessels and ligaments) • Muscle used for the movement contain higher level of collagen (muscles found in neck, shoulder, leg, flank)

  10. Meat Composition • Effect of Collagen on TendernessPrimary Protein • Pearly White Tough Fibrous Protein • Supports Muscle • Prevents Overstretching • Effect of Age on Tenderness • Effect of Elastin on Tenderness

  11. Fatty tissue (adipose tissue) • Serves as insulation under the skin (subcutaneous fat) and padding fat in abdominal cavity for sensitive internal organs. • Serves to retain the moisture of the muscle and to protect the flesh from the action of microorganisms (Cover or separable fat) • Deposited in a small lakes throughout the muscle and this is known as marbling

  12. Adipose Fatty Tissue • Fat Color & Texture Affected By Age Diet Species • Bone Marrow Soft Fatty Material Yellow Red

  13. Adipose Fatty Tissue Animal Age Diet Species Affect Color & Texture of Fat White Younger Animals Yellow Older Animals Feed Rich in PUFA −› Pork Higher in PUFA

  14. Meat color • Myoglobin • Hemoglobin • Cytochromes • Flavins • Vitamin B12

  15. Concentration of myglobin depends on • Species (beef 0.50%, lamb 0.25%, pork 0.06%) • Age of animal (older animal-darker meat) • Amount of exercise and stress (frequently exercise muscle are darker, organ meats are also darker-greater supply of oxygen) • Conditions of storage and processing

  16. Effect of processing • Exposure to oxygen (fresh cut) brings about oxygenation of myglobin (bright red color) • Oxygenation-formation of complex between the Fe+2 and O2 • Storage – lead to oxidation of myoglobin Fe+2→ Fe+3 –metmyoglobin ) brownish color. • Effects of Heat on Pigments Initially Converts Raw Meat to Bright Red Denature Pigment-Containing Proteins −› Well-Done Meat Grayish Brown Metmyoglobin Storing Meat −› Yellow Green Faded • Curing leads tp formation of nitrosylmyoglobin. Cooking – nitrosyl hemochrome (pink color of cured meat)

  17. Effect of curing and heating on meat pigments

  18. ATP Adenosine Triphosphate Universal Energy Compound Metabolism of CHO Fat Protein High-Energy Phosphate Bonds Fuels Cellular Chemical Activity Muscle Fibrils Sarcomeres Actin & Myosin Actinomyosin Muscle Contraction and relaxation Muscle Contraction & Relaxation

  19. When the animal is slaughtered • First the muscle are flabby and soft • 6-24h the muscle undergoes a stiffening process known as rigor mortis • meat cooked during rigor mortis is tough and dry • rigor mortis is initiated by the loss of ATP and decrease in pH • The decrease of pH is the result of formation lactic acid. Lactic acid is the breakdown product formed during glycolysis of glycogen and ATP is produced. • ATP stimulate the anaerobic breakdown of glycogen and keep the muscle relaxed • When the ATP is gone actin bind to myosin irreversibly- muscle undergoes a stiffening called rigor mortis.

  20. Rigor Mortis Natural Tenderizing • Rigor Mortis pH 5.8 Latin “Stiffness Of Death,” Temporary Stiff State Muscles Contract • Improperly Handled Meat Dark-Cutting Beef PSE Pork Pale Soft Exudative Pork Thaw Rigor Cold Shortening

  21. Usual elapsed time between slaughter and the passage of rigor mortis • fish- 1-7 hours (unless stored in ice) • chicken- 4 hours or more • turkey -12 hours or more • pork - 1 day • beef -11 days

  22. Rigor mortis-problem • Pale-Soft-Exudative (PSE) typical for pork, brought about by rapid glycolysis - meat warm when its pH decrease markedly; this causes considerable denaturation of sarplosmasmic protein and their absorption by myofibrillar proteins. PSE is displayed by reduced water binding properties of meat. • Dark Cutting - common in beef. Animal under stress before slaughter-marked depletion of glycogen. pH of meat at rigor mortis high. As result meat has good water binding water, dark color and poor resistance to microbial decay • Cold shortening- when rigor mortis occurs at temperature below optimum temperature - greater shrinkage of muscle. • Thaw rigor-meat frozen pre-rigor, rigor occurs during thawing, greater drip, less juicy meat.

  23. Resolution of rigor mortis • Pre-rigor meat pH 6.9-7.1 • Final pH at rigor 5.7-5.9 • This low pH increase resistance of meat to microbial decay, lighten color • Low pH activates cathepsins - their activity leads to resolution of rigor mortis

  24. Tenderness of meat depends on • Formation of actinomyosin • presence the solubility of connective tissue • age of animals • Degree of aging • processing methods

  25. Aging methods • Dry aging 1-3 C, <70%, 3-6 weeks • Wet aging 1-3 C, 85-80%, 1-2 weeks • Fast aging room temp, 1-2 days, 85-90% Carcasses Hung in Refrigeration for Reversal of Rigor Mortis

  26. Aging/Tenderizing Methods • Enzymes Proteolytic Enzymes: chymotrypsin, papain, peptidase • Salt ↑ H2O Retention Capacity • Acids Marinades w/ Acids or Alcohol • Mechanical Tenderization Grinding Cubing Needling Pounding • Electrical Stimulation Beef Cattle Sheep • Hot boning

  27. Carcasses are cut into: • Two Major Types of Meat Cuts, Wholesale And Retail.

  28. Retail cuts: • There are 314 retail cuts of meat from beef, pork, veal and lamb • Cuts of meat can be identified by size, and shape of the bones and muscles. • Bones used to identify the seven groups of retail cuts include: • Blade cuts (blade bone near the neck) • Arm cuts (arm bones) • Short loin cuts (back bone, T-shape bone) • Sirloin cuts (pin bone, flat bone, wedge bone) • Round cuts (leg and round bone) • Breast (breast bone, rib bones) • Rib cuts (back bone, rib bones)

  29. MEATCOMPOSITION

  30. MEATCOMPOSITION

  31. Beef-tender cuts • Club steaks-the smallest steaks in the short loin; the first cut from the rib end of the loin • Beef loin T-bone is cut behind the club steaks • Porterhouse steaks are cuts from the end of short loin • Top loin steak when the tenderloin is removed from the short loin and divided into steaks • Flat bone sirloin steaks • Tenderloin steaks cuts that come from the stripped tenderloin muscle. Can be divided into bifteck (3-4 steaks from the larger end; next 4 inches is called chateaubriand, followed by filet steaks, while filet mignon steaks are cut from the small end of the tenderloin.

  32. Beef -less tender cuts: • Round steaks • chuck and blade stakes • shoulder steaks • shoulder arm steak • flank steaks • rump • top round roast • bottom round roast • chuck eye or blade roast • brisket • short ribs • skirts steaks

  33. Variety meats • liver • tongue • kidney • hearts • tripe (a stomach lining of beef animal; honeycomb-lining of the second stomach; smooth-lining of the first stomach) • sweetbreads (thymus glands and pancreas) • brains • lungs • brains, sweetbreads, liver, kidney from young animals are tender • tongue, heart, tripe, beef and pork kidney, beef liver -less tender. • Organs always should be cooked to well done stage to minimize danger of transmitting parasitic organisms.

  34. Variety Meats Liver Sweetbreads (Thymus) Brain Kidneys Heart Tongue Tripe (Stomach Lining) Oxtail (Tail of Cattle)

  35. Goals of meat cooking • To change color • To improve flavor • To make meat more tender • To destroy harmful microorganisms

  36. Safety of meat cooking • 60 C, moist heat for 10 min kills only molds and yeasts • 65 C, moist heat for 12-15 min kills most bacteria • 74-100 C, moist heat kills most pathogenic bacteria • Trichinella spirallis is at 58 C but regulations required pork to be heated to at least 71 C

  37. Recommended final temperatures of cooked meat – beef and lamb • rare: rose red center, pinkish toward outer portion, shading into a dark gray, brown crust, juice bright red, 60 C • medium: light pink, brown edge and crust, juice light pink 70 C • well done: brownish-gray center dark crust, 77 C • Pork, veal, game meat always to well done

  38. Dry heat methods-tender cuts • Roasting • Broiling • Pan-broiling • Grilling • Pan frying • Frying

  39. Meat cooking • Broiling & Grilling Times Based on Meat’s Thickness & Distance from Heat

  40. Wet heat methods less tender cuts • Braising • Simmering • Stewing • Poaching • Steaming • Slow cooking

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