Food Chemistry - Meat

Food Chemistry - Meat

• Meat is animal tissue used as food. It most often refers to skeletal muscle and associated fat, but can also include non-muscle organs like lungs, liver, skin, brains, bone marrow and kidneys.
• Common sources of meat in the Philippines include pig, goat, carabao, cow, chicken, and horse.

US Per Capita Meat Consumption (1970-1996)

• Data presented as retail weight shows yearly consumption of various meats. This includes Beef, Veal, Pork, Lamb, Chicken, Turkey, Fish, and the Total consumption in pounds/kg for each year.

Heme Iron Sources

• Data presented in a table shows milligrams of iron per 3 oz serving of cooked meat. Beef in the form of calves liver and sirloin, pork with ground, lean, tenderloin and ham, Lamb with loin, Veal with loin and Chicken with breast.

Total Fat (grams) from 3 Ounce Servings (separable lean only)

• A bar chart displaying the total fat in grams from various meats. Specific cuts of beef, pork, lamb, and chicken are listed.

Calories from 3 Ounce Servings (separable lean only)

• A bar graph showing the caloric content of various meats for 3 oz servings (separable lean only). Various cuts of beef, pork, lamb, and chicken are listed.

Cholesterol (mg) from 3 Ounce Servings (separable lean only)

• A bar chart demonstrating cholesterol content for various meats. Specific cuts by beef, pork, Lamb, Chicken are shown.

Pork

• Pork is the culinary name for meat from domestic pigs (Sus scrofa), often specifically for fresh meat.
• It's one of the most commonly consumed meats worldwide, with nearly 100 million metric tons in 2006, according to USDA data.

2006 Worldwide Pork Consumption

• Data presented in a table form demonstrates the metric tons and per capita (kg) consumption for various regions, including China, EU25, US, Russia, Japan, and Others.

Beef

• Beef is the culinary name for meat from bovines, primarily domestic cattle. Cuts include steaks, pot roasts, short ribs, and ground beef. Blood can be used in blood sausage varieties.

Veal

• Veal is meat from young calves, often male, renowned for its delicate taste and tender texture.
• Best age for veal is 4-14 weeks, and the meat is hung for 8 days before use.

Lamb, Hogget or Mutton

• Lamb, hogget, and mutton are culinary terms for the meat of domesticated sheep.
• Lamb refers to sheep one year old or younger
• Hogget and mutton are for older sheep
• The quality of meat is most optimal for sheep aged 2-4 years old.

Goat Meat

• Goat meat has a taste similar to lamb. It can be prepared via stewing, currying, baking, grilling, barbecuing, mincing, canning, or sausage-making. Nutritionally, goat meat is healthier than mutton; it is lower in fat and cholesterol and comparable to chicken; it also has more minerals and is lower in total and saturated fats than other meats.

Horse Meat

• Horse meat is meat cut from horses. It has a slightly sweet, tender texture, low in fat, and high in protein.

Sausage

• Sausage is a food typically containing ground meat, animal fat, salt, spices, and sometimes other ingredients (like herbs). It can be fresh or preserved by curing or smoking.

Classification of Sausage

• Cooked sausages
• Cooked smoked sausages
• Fresh sausages
• Fresh smoked sausages
• Dry sausages

Hot Dog

• A hot dog is a fully cooked, cured, and/or smoked moist sausage, with a soft, even texture and flavor. Traditionally made from beef, pork, or a combination.

Ham

• Ham is the thigh and rump of a slaughtered animal, commonly for pork.

Storage and Preservation of Meat

• Drying: An ancient food preservation method often used with salting and curing. It minimally affects water-holding and aroma characteristics.
• Cooling/Freezing: Freezing meat extends its preservation/shelf life and slows down lipid oxidation.
• Curing: Preservation and flavoring, typically with a combination of salt, sugar, and nitrate/nitrite. Many curing methods include smoking.
• Salting: Adding salt inhibits spoilage by drawing water out of microbial cells via osmosis.
• Smoking: Adding flavor, cooking, and preserving food with smoke from burning/smoldering plant materials (e.g., wood).

Heating

• Heating meat results in grayish-brown color, protein coagulation, juice release, decreased water-holding capacity, and an increased pH value.

Tenderizing

• Tenderizing meat using plant enzymes (ficin, papain, bromelain)
• This process prepares the meat for optimal tenderness.

Suggested Storage Times (Raw Meat)

• This presents a table listing product types and their suggested refrigerated and freezer storage times.

Meat Aroma

• Raw meat has a weak aroma.
• Heating enhances the aroma which is composed of nonvolatile flavor substances, flavor enhancers, and volatile aroma constituents.

Meat Composition

• Water: ~75%
• Protein: ~18%
• Lipid: ~3%
• Non-protein nitrogen: ~1.6%
• Carbohydrate: ~1.2%
• Minerals: ~0.7%
• Traces of vitamins: (etc.)

Physical Composition of Meat

• This is a high-level topic heading

Muscle Cells

• Unique for converting chemical energy (ATP) into mechanical energy, enabling work.
• The basic unit is the muscle cell, 10-100 μm by several centimeters long.

Muscle Structure

• Detailed diagram and labels of muscle structure.

Sarcolemma

• Thin membrane surrounding each muscle fiber.
• Motor nerve endings terminate on sarcolemma, crucial for signal transmission to initiate contraction.

Sarcoplasm

• Fluid within muscle fibers where myofibrils are suspended. Typical quantity of myofibrils present in a muscle fiber is about 2000.

Muscle Fiber Divisions

• Diagrams and labels describing the epimysium, perimysium, and endomysium. These tissues encase and organize muscle fibers and bundles.

Myofibrils

• Proteins within the myofibril form thick and thin filaments.
• The arrangement produces visible light/dark patterns, detailed by electron microscopy.

Thick Filaments

• Primarily composed of myosin protein.
• The A band contains myosin and comprises about 45% of muscle protein.
• Myosin's molecular weight is ~470,000-480,000.
• There are approximately 400 myosin molecules per thick filament.
• Diagrams and labels showcasing detailed myosin proteins.

Thin Filaments

• Composed primarily of actin protein (about 20-25% of muscle protein).
• Actin exists in two forms: G-actin and F-actin.

Thin and Thick Filaments

• A diagram showcasing the arrangement of thin (actin) and thick (myosin) filaments within the myofibrils.

Actin

• G-actin and F-actin are defined and explained in detail, their molecular weights are stated.
• The structural properties (e.g., alpha helix) are noted for each form.

Tropomyosin

• A detailed explanation and values for tropomyosin's structural properties (e.g., alpha helix form, % of muscle protein, length, MW).

Connective Tissue

• Elastin and collagen are explained, their functions in muscle are described. Collagen is the principal protein; it is composed of tropocollagen units. A tough muscle holds more collagen, and treatment by "moist heat" converts collagen to gelatin.

Adipose Tissue

• Adipocytes (fat cells) are classified. Surface fat (subcutaneous) and intramuscular fat (marbling) are defined and linked to meat quality, tenderness, and flavor.

Post-mortem Changes in Muscle

• Biochemical reactions post-mortem that transform muscle into meat are described and explained.
• Aerobic and anaerobic pathways are important during the death and aging of the animal, their functions are outlined.
• The conversion of d-glucose to lactic acid and pH changes in the animal tissues are relevant elements that change during the meat's aging.

Effect of pH on Meat Quality

• A rapid decrease in pH causes muscle protein denaturation, leading to a loss of water holding capacity and pale myoglobin color.
• A high pH results in a darker meat color and drier meat surfaces.

pH Decline in Meats

• Graph of pH decline during 24 hours postmortem for different meat types (normal, DFD, PSE).

Generation of Meat Flavor Potentiators During Aging

• Aging processes convert ATP to ADP, then AMP, and finally to IMP (inosine monophosphate) and ammonia—these molecules contribute to the characteristic flavors of cooked meat.

Rigor Mortis and Aging

• Rigor is a post-mortem stiffening of the carcass. The explanation focuses on the depletion of ATP in muscle cells which prevents the actin and myosin proteins from detaching, resulting in rigor mortis. The aging process is the process of relaxing the muscle tissues. -The aging process results in changes in the muscle tissue.

Explore the fascinating aspects of meat as food, its sources, and nutritional values. This quiz covers various topics such as per capita meat consumption in the US from 1970-1996, heme iron sources, and fat content in different meat cuts. Test your knowledge and learn more about the chemistry behind meat.