Meat

Question 1

What is the composition of meat?

Answer 1

• Water: 75%
• Protein (complete): 15-20%
• Fat: 5-40%
• Carbohydrates: basically 0%
• Vitamins and minerals: iron (heme, small amount but good source), phosphorous (excellent source), niacin/riboflavin (excellent source), thiamin (good source)

Question 2

What are the types of proteins in meat and their functions and protein examples?

Answer 2

1. Myofibrillar
   - Function: contractile
   - Proteins: myosil and actin
   - Found in muscle/flesh of meat
2. Sarcoplasmic
   - Function: transport oxygen
   - Proteins: myoglobin (responsible for colour of meat, found in flesh), hemoglobin (found in blood)
3. Mitochondrial
   - Function: chemical reactions
   - Proteins: enzymes
4. Connective
   - Function: structural
   - Proteins: collagen, elastin
   - Responsible for holding muscle to the bones, found in connective tissue of meat

Question 3

What are the muscle fibre proteins and what occurs when you add heat?

Answer 3

• 2 proteins found in sarcoplasm of muscle fibres:
• Myosin (thick filaments) and actin (thin filaments)
• Heat causes denaturation and coagulation of muscle proteins
• Overheating causes over-coagulation = tough meat
• Muscle fibre proteins shrink and squeeze out water due to excessive hydrogen bonds forming = dry meat

Question 4

What are the connective tissue proteins and what occurs when you add heat?

Answer 4

1. Collagen: important role in determining tenderness
   - More collagen = less tender
   - Can be hydrolyzed into gelatin (more tender kind of meat) by various cooking methods
2. Elastin: rubber-like protein, really chewy
   - Not affected by normal cooking procedures
   - Must be removed

Question 5

What is rigor mortis? How do you counteract it?

Answer 5

• Immediately after slaughter muscles are in contracted state = tough meat
• If meat is aged (held for specific period of time under controlled temperature conditions or 1-2 C) = increase in tenderness (muscles start to loosen)
• Proteolytic enzymes (cathepsins) in meat slowly break down bonds holding muscles in contracted state = increase in tenderness
• Meat is hung during aging = gravity stretches muscles, releasing them from contracted state

Question 6

What are the factors influencing meat tenderness?

Answer 6

1. Length of aging (rigor mortis)
   - Tenderness increases as aging time increases
2. Age of animal
   - Amount of connective tissue increases with age of animal
   - Meat from young animals (pork and lamb) is more tender
3. Different species (beef vs pork vs chicken)
   - Due to different amounts of connective tissue (ie. more muscles)
4. Specific muscle in animal
   - Tenderness varies between muscles within same animal (some are stronger, exercise makes muscle fibers expand)
   - Depends on amount of connective tissues in the muscle
   - Most tender beef cut = tenderloin (filet mignon)
5. Method of cooking
   - Moist heat cooking methods increase tenderness of less tender cuts

Question 7

What is marbling? What are the types and which are juiciest?

Answer 7

• Fine white streaks or pockets of fat running through the lean part of a cut of meat
• 4 categories of marbling: trace, slight, small, modest
• Marbling enhances flavour and juiciness as many flavour elements found in fat
• Juicier (flavour) meat gives greater perception of tenderness (texture)

Question 8

What are the Canadian beef grades?

Answer 8

• Canada Prime: must have slightly abundant marbling or higher
• Canada AAA: must have small marbling or higher
• Canada AA: must have at least slight marbling but less than small
• Canada A: must have at least trace marketing but less than small
• In Canada you cannot sell beef with hormones and antibiotics

Question 9

What is Kobe beef?

Answer 9

• Exclusive grade of beef from cattle raised in the province of Tajima, Japan
• Kobe is the capital
• Pampered black-haired Wagyu cattle
• Massaged with sake (rice wine)
• Strictly controlled diet that includes beer mash in the summer to stimulate appetite
• Receive very little exercise and daily massages (“mellow, relaxed cows make good beef”)
• Extraordinary tender, full flavoured
• Very expensive ($500 per kg)
• Looks intensely marbled, looks like “it has been left out in the snow”
• Ratio of marbling to flesh is 10 times higher than any other beef
• Requires very, very careful cooking
• Pre-heated, extremely hot cast iron frypan or grill
• Crispy sear on outside
• Served “blue” or very very rare inside

Question 10

What are the tender cuts of meat?

Answer 10

Along the vertebrate

1. Rib steak/roast
   - Rib wholesale cut
   - Rib bone
2. Wing steak (looks like rib steak)
   - Loin wholesale cut
   - Rib bone
3. Sirloin steak/roast
   - Sirloin wholesale cut
   - Wedge or hip
4. T-bone steak (small tenderloin piece)
   - Loin wholesale cut
   - 1/2 vertebra
5. Porterhouse (bigger tenderloin piece)
   - Loin wholesale cut
   - 1/2 vertebra

Question 11

What are dry heat cooking methods?

Answer 11

• High temperature (> or = 160 C)
• Short period of time to prevent overcoagulation which would lead to tough/dry meat
• No water at all

Question 12

What are the types of dry heat cooking methods?

Answer 12

Used for tender cuts of meat

1. Beef: less exercised areas of carcass (rib, loin, sirloin wholesale cuts) = contain less connective tissue (less collagen and elastin) = smaller diameter muscle fibres
2. Pork and lamb: young animals = less connective tissue - small diameter muscle fibres
3. Chicken and fish: little connective tissue, short and small muscle fibres
   - Long, moist heat cooking is not required because of less connective tissue
   - Use dry heat methods in order to keep distinctive flavour

Question 13

What kinds of meat are cooked using the dry heat cooking methods?

Answer 13

1. Broiling, frying, pan-broiling, BBQing, and deep fat frying
   - Used for thin cuts (steaks, chops)
2. Baking/roasting
   - Used for larger, thicker cuts (beef or pork roasts, whole chickens)

Question 14

What happens when you overcook beef/pork/chicken?

Answer 14

• Too high a temperature or cooking too long
• Very easy to overcook tender meats
• Occurs more readily with dry heat methods
• Overcooking causes overcoagulation of muscle fibre proteins (actin and myosin)
• Results in toughness
• Overcoagulated proteins shrink and squeeze out water
  Results in dryness
• This is why people associate juiciness with tenderness

Question 15

What happens when you overcook fish?

Answer 15

• Cooked fish flakes easily and is opaque in appearance
• Overcooking over-coagulates muscle fibre proteins = tough fish
• Over-coagulated proteins squeeze out water = dry fish, high concentration of fish flavour

Question 16

What are the less tender cuts of meat?

Answer 16

1. Blade steak/roast
   - Chuck wholesale cut
   - Shoulder blade or rib
2. Round steak/roast
   - Hip wholesale cut
   - Leg bone
3. Brisket
   - Brisket wholesale cut
   - Boneless
4. Stewing beef
   - Shank wholesale cut
   - Boneless
5. Ground beef
   - Chuck (neck) wholesale cut
   - Boneless

Question 17

What is the difference between steaks and roasts?

Answer 17

Steaks are thinner.

Question 18

What are moist cooking methods?

Answer 18

This method allows moist heat and low temperatures for a longer cooking time to allow hydrolysis of collagen connective tissue protein into gelatin = increased tenderness (elastin protein in connective tissue is not affected by cooking ∴ cut out)

• Temperature of ≲ 100 C (low)
• Longer cooking times
• Use of water

Question 19

What are moist cooking methods used for? Discuss veal.

Answer 19

• Less tender cuts of beef: chuck, shank, brisket, plate, hip, and flank wholesale cuts
• Receive more exercise
• More connective tissue (collagen and elastin)
• Larger diameter of muscle fibres

Veal

• From very young beef animals; male (bull) dairy calves
• Bull calves not needed for reproduction to replenish milking herd (not much use, can’t produce milk, not used to produce beef) so made into veal
• Milk fed: raised on balanced diet containing all necessary nutrients for animal health; light pink colour; mild taste; soft texture; reach market weight of 205-225 kg; 5-7 months
• Grain fed: milk based diet for first 6-8 weeks then corn and protein supplement added; darker pink colour; similar flavour to beef but not as strong; market weight is 300-320 kg
• High proportion of connective tissue to muscle/flesh because of shorter time for muscle development = less tender

Question 20

What types of moist cooking methods are there?

Answer 20

1. Braising of ribs, steaks (less tender), and chops
   - Used for thin cuts
2. Pot roasting
   - Larger cuts
3. Stewing
   - Small pieces of meat
4. Pressure cooking (use water + high pressure = more hydrolysis of collagen into gelatin)

Question 21

What are other ways to tenderize meat other than moist cooking methods?

Answer 21

1. Marinate meat
   - Place raw meat in a seasoned liquid (marinade) which contains an acid ingredient in order to tenderize the meat and add flavour
2. Mechanical action (chopping, grinding, pounding)
   - Breaks up large diameter muscle fibres
   - Breaks up connective tissue
   - Increases surface area, allowing more area for heat and moisture to hydrolyze collagen into gelatin
3. Acid (beer, wine, lemon juice, tomato juice, etc.)
   - Added to raw meat (eg. marinating meat)
   Increases water holding capacity of muscle fibre proteins actin and myosin = increase in juiciness (the only way to increase juiciness)
   - If you go on and cook meat in acid, acid hydrolyzes collagen connective tissue into gelatin (2nd reaction) = increase in tenderness
   - Lab example: veal scallopine
   - If you add acid to partially cooked meat (searing edges of meat to cause browning reaction to increase flavour, still raw on inside), acid hydrolyzes collagen connective tissue into gelatin (1 reaction) = increase in tenderness only
   - Lab example: swiss steak in tomato sauce, pork in barbeque sauce
4. Proteolytic enzymes
   - Eg. papain from papayas, ficin from figs, or bromelain from pineapple
   - Hydrolyzes peptide bonds between amino acids (break carboxyl and amine linkage), or in other words muscle fibers
   - Affects both collagen and elastin connective tissue proteins
   - Amount of enzyme and length of time must be carefully controlled
   - If not controlled, meat becomes mushy in texture because myosin and actin are hydrolyzed
5. Moist heat and low temperatures (<100 C) for a longer cooking time
   - Allows hydrolysis of collagen connective tissue protein into gelatin = increased tenderness
   - Elastin protein in connective tissue is not affected by cooking

Question 22

What is the Maillard browning?

Answer 22

• Surface browning (if coat in flour, then it is dextrin browning reaction)
• Nonenzymatic browning reaction
• Occurs in high heat, low moisture conditions (dry heat cooking methods only)
• Occurs on the surface of meat and baked products (muffins, tea biscuits, cakes)
• Reaction between: amino acids (protein) + reducing sugar + [dry heat conditions] = melanoids (brown coloured pigments)
• Reducing sugar is glucose in meat, fructose, lactose in baked products and galactose, NOT SUCROSE (white sugar) as it is not a simple sugar (can be further broken down)

Question 23

What are the pigments responsible for meat colour?

Answer 23

Involves 2 chromoproteins (complex proteins; coloured material attached to simple protein)

1. Myoglobin (pigment): in the muscle, 80-90% of meat colour
2. Hemoglobin: in the blood, 10-20% of meat colour

Question 24

What is the structure of myoglobin?

Answer 24

1. Globin
   - Protein portion of molecule
   - Denatures during cooking = colour change in meat
2. Heme
   - Nonprotein portion of muscle
   - Ring structure
   - Contains conjugated double bonds; lets pigment absorb light in visible range of spectrum
   - Never changes, doesn’t affect meat colour
3. Central Fe atom
   - Found in centre of heme
   - Exists in reduced (Fe 2+) or oxidized state (Fe 3+) = colour change in meat
4. Water molecule
   - If replaced by oxygen or nitric oxide = colour change in meat

Question 25

What is the process of meat colour in fresh meat?

Answer 25

1. Myoglobin: purplish colour
2. Oxygenation: reaction involving addition of 2 O2 atoms to myoglobin to form oxymyoglobin
   - Water molecule in myoglobin is replaced with oxygen
   - Colour changes from purple-red to bright-red
   - Meat in grocery stores is in oxygen-permeable wrap
3. Metmyoglobin (brownish-red) forms when oxygen is depleted
   - Covering meat with wrap that is not permeable to oxygen
   - Coating meat in flour or in marinade (oxygen cannot get in), or having meat stacked on top of each other
4. Reducing substances: chemicals in meat which keep Fe in reduced state (Fe 2+)
   - When these reducing substances are depleted, iron atom is in oxidized state (Fe 3+)
   - Reducing substances are used up by:
   - Storing the meat at higher temperatures
   - Microorganisms growing and multiplying (as meat ages, you start to notice grey-brown colour, odour, and slime)
5. When you cook meat, you get denatured globin hemichrome (internal)
   - Brown or grey-brown colour of fresh meat cooked to well done
   - Cooking denatures globin protein portion of pigment
   - Central iron atom moves to oxidized state (Fe 3+) from the heat

Question 26

What is the process of meat colour in cured meat?

Answer 26

1. Covering raw meat with curing mixture
   - Excludes oxygen
   - Converts myoglobin or oxymyoglobin into metmyoglobin
2. Water molecule attached to metmyoglobin is replaced by nitric oxide (NO)
   - NO is produced from sodium nitrite in curing mixture
   - Nitric oxide myoglobin forms = red/pink colour
   - The result is the characteristic colour of raw, cured meat
3. When cured meat is cooked, nitrosyl hemochrome is formed
   - Globin (protein) portion of nitric oxide myoglobin pigment is denatured by heat
   - Nitric oxide is still attached
   - Colour of cooked, cured meat (interior) = intense pink

Question 27

What is cured meat? How does it get that way?

Answer 27

• Usually pork, beef, and chicken are cured
• Eg. bacon, ham, corned beef, salami, pastrami, and some sausages
• Involves applying a curing mixture to fresh meat which can be in the form of a liquid or dry rub/mixture

1. Salt
2. Sodium nitrite (similar to marinade which contains acid but instead contains this ingredient)
   - Causes unique colour and flavour changes
   - Contains nitric oxide to inhibit Clostridium botulinum spores

• Cured meats are often vacuum packaged = anaerobic conditions = preservation, longer storage
• Amount used in cured meats has been greatly reduced because during cooking at high temperatures, sodium nitrite is converted into nitrosamines (carcinogens; linked to causing cancer)
• Therefore, limit consumption of cured meats + cook using medium rather than high temperatures

3. Seasonings/flavouring

Question 28

Explain salmon’s colour.

Answer 28

• Pigment = astaxanthin (carotenoid family)
• Very stable (may be slight fading) during cooking, becomes more opaque
• Methods used are dry-heat: broiling/grilling/BBQ
• Allows surface browning/non-enzymatic Maillard browning reaction to occur

Question 29

What are the cooking losses when you cook meat

Answer 29

1. Evaporation of water
   - Occurs more with dry heat methods (>100 C)
   - Lower in rare than well-done meat
2. Drip loss (fat, fat-soluble vitamins, pigments, some protein)
   - Higher with moist heat, but retained in sauce/gravy
3. Nutrients
   - Higher with larger surface area
   - Greater loss of b-vitamins (especially thiamin)
   - Higher loss with increase in temperature (more common in dry heat than moist heat)

Question 30

Is salmon cooked in the microwave a dry heat method?

Answer 30

In lab, salmon in microwave and corned beef is not considered dry heat cooking because water in meat turns into steam.

Stoves have vent to allow steam to evaporate but microwave does not so the environment becomes very moist.