Meats Flashcards
1
Q
What is the definition of meat? Why does it exclude poultry and fish?
A
- muscles of mammals; can include organs and glands
- Because “non-mammals”
2
Q
How are beef classified?
A
By age and sex
3
Q
Name the 4 types of beef.
A
1) Steers (M) (castrated young to gain weight quickly)
2) Bulls (M) (uncastrated, processed meats and pet foods)
3) Heifers (F) (no born calves) and Cows (F) (birth to less than one calf, less desirable)
4) Calves (F) (M) 3-8, baby beef (8-12 months)
4
Q
What are veals? What is their diet?
A
- Young calves M, F
- 3 weeks to 3 months
- Restricted movement
- Milk-based diet or formula
5
Q
How is the meat of veals?
A
- Milky flavour
- Pale colour
- Tender (slightly less if free-range)
6
Q
Name the 2 types of sheep.
A
1) Lamb (< 14 months)
2) Mutton (> 14 months)
7
Q
How is the meat of mutton?
A
- Darker, tougher meat
* Stronger flavour
8
Q
Name the 3 types of pork.
A
1) Swine (F) (M) - slaughtered at 7-12 months
2) Pigs (<4 months)
3) Hogs (> 4 months)
9
Q
What is the composition of meat?
A
- H2O (75%)
- Muscle
- Connective tissue
- Adipose tissue (fat)
- Bone
10
Q
What is the primary source of dietary meat?
A
Skeletal muscle
11
Q
Name 3 characteristics of skeletal muscle. What do they impact?
A
- Connective tissue
- Muscle fibers (cells)
- Fibrils
- -> impacts cut of meat (tender or tough)
12
Q
What are muscle fibril composed of?
A
2 sarcomere units
13
Q
What does each sarcomere contain? How are the sarcomeres shortened? What is consumed?
A
- 2 protein filaments:
- Actin (thin) + Myosin (thick) –> Actomyosin
• Filaments slide across each other forming actomyosin(cross-links), which shortens the sarcomere
• ATP consumed
14
Q
Where is connective tissue found?
A
ligaments and tendons
15
Q
What is the composition of connective tissue?
A
proteins + mucopolysaccharides
16
Q
What are the 3 functions of connective tissue?
A
- Surrounds all living cells
- Provides structure and adhesiveness
- “Glue” that holds muscle fibers together
17
Q
What are the two connective tissue proteins?
A
Elastin and reticulin
18
Q
What forms connective tissue proteins?
A
Collagen
19
Q
What is the most abundant protein in connective tissue?
A
Collagen
20
Q
What does animal maturity lead to in terms of collagen?
A
↑ collagen content
↑ covalent cross-links between collagen strands
21
Q
How does the cut affect collagen? (2)
A
• Cuts high in connective tissue: ↑ collagen
• Avoid cuts in muscles for movement
-> Neck, shoulders, legs, flank
22
Q
What is elastin?
A
- Yellow and rubbery (silver skin)
- Elastic qualities duh!
- Small amounts in meats (except cuts from neck and shoulder)
23
Q
What is reticulin?
A
- Fine mesh network
* Supports tissues (e.g. bone marrow, liver, and lymphatic system)
24
Q
Why does elastin have to be removed?
A
because does not soften with heating
25
What is subcutaneous fat?
* Fat under skin
* Insulation
* Padding in abdominal cavity for sensitive organs
26
What is intramuscular fat?
* Fat within muscle fibers
* Creates marbling
* Seen as little, white streaks or drops
27
How does the animal's age affect fat?
Colour
| Young animals (white) --> Older animals (yellow)
28
How does the animal's diet affect fat?
Type
| High PUFA diet in swine -> Pork is also high in PUFA
29
How does the animal species affect fat?
Softness
| Lamb (hard, brittle, dense) vs. Beef (soft)
30
What are landmarks to identify various meat cuts from carcass?
Bone
31
What is bone marrow?
Soft, fatty material in center of large bones
32
What colour is bone marrow in long bones? In spongy center of other bones?
1) Yellow – in long bones
| 2) Red – in spongy center of other bones
33
What gives meat its colour?
Myoglobin and Hemoglobin
| -> proteins found in meat that give meat its pigment
34
Differentiate myoglobin and hemoglobin.
Myoglobin: Receives O2 from blood and stores it in muscles
Hemoglobin: Transports O2 throughout body
35
Name the 3 factors that increase myoglobin (darker red).
1) Increased exercise (higher O2 demand, more myoglobin)
2) Increased animal age (increased myoglobin, beef more than veal, mutton more than lamb)
3) Species (red meats - beef and lamb carry more red than pork)
36
What is the structure of hemoglobin?
4 protein polymer strands and 4 heme molecules
37
What are the 3 stages of myoglobin following slaughter? What does it depend on?
1) Slaughter - myoglobin - purplish-red (O2 depleted)
2) Meat Cut from carcass - oxymyoglobin - bright red (indicator of freshness)
3) Storage - metmyoglobin - brownish red (bacteria, O2, light)
- > depends on the oxidation and reduction of the iron
38
What happens to myoglobin when it is heated?
1) Cooking
2) Well-done meat
3) Storage
- Denatures myoglobin
Cooking, bright red
Well-done meat, grey
Storage (too long), yellow, green, faded
39
What does the food industry add to meat to keep from browning? What colour does it give
Nitrite, gives it its pink colour
40
What gives meat its flavour? What is this group called? Is it soluble?
- Called extractives
- Non-protein nitrogen substances that are the end products of protein metabolism
- Water soluble
41
What is a trick to recapture meat flavour lost during boiling/simmering?
use cooking liquids for soups/gravy
42
Why are older meats more flavourful?
Higher in connective tissue and extractives
43
What is meat not a good source of? What is the richest source of carbohydrate?
Fiber
• Vitamin C
• Carbohydrate (little, liver is the richest source)
44
What are the nutrients composed in meat?
Water (75%)
Protein (25%)
Fat (varies)
B Vitamins and Minerals
45
How many meat portions should you have according to Canada's Food Guide? What is one serving?
- 2-3 servings
| - 75 grams = size of palm
46
What are some tips to minimize fat from Canada's Food Guide?
- Select lean or extra lean cuts of meat (ex: round roast, sirloin steak, lean
ground meat)
- Game meat: bison, caribou, deer, elk and moose
- Trim visible fat!
47
Why is meat an excellent source of protein? How do you receive remaining protein needs?
- High-quality protein
- Meat provides most of daily protein needs
- Remaining: other food groups like dairy (milk, cheese)
48
What affects amino acid score? What is the reference protein?
Digestibility
| Eggs
49
How does the IARC classify meat and cancer?
- Red meat "probable" cause of cancer
- Processed meat "definite" cause of cancer
- 2011 meta-analysis: 17% increased relative risk of developing bowel cancer
- HAZARD identification, NOT risk assessment --> risk is not that high
50
How does red meat cause cancer?
1) Haem (hemoglobin)
• Broken down in gut to form N-nitroso compounds
• Damages intestinal cell lining
• To heal, DNA replication is initiated
• ⬆ chances of errors (DNA mutations) --> risk of cancer
2) High-Temperature Cooking
• Grilling or barbequing
• Produces chemicals that increase cancer risk
51
What B vitamins are composed in meat? What is their main role?
- B1, B2, B3, B6, B12, some folate
• Help body cells convert food (carbohydrates) into
fuel (glucose) to produce energy
• Metabolize fat and protein
52
What is thiamin's role?
* B1 used to make ATP, the fuel of every cell in the body
| * Main role: helps body metabolize carbohydrates and proteins
53
What is riboflavin's role?
• B2 aids in the production of niacin (B3) and pyridoxine (B6)
54
What is pyridoxine's role?
* B6 used to create protein and glycogen, stored as energy in muscles and liver
* Helps form hemoglobin
55
What is vitamin B12's role? Where is it found? What % of older people don't absorb vitamin B12 as efficiently?
• DNA, red blood cells, and nervous system
• Found only in animal foods (meats & dairy)
and fortified foods.
• 10-30% of older people may not absorb vitamin B12 as well
56
What is the precursor for niacin? What is its role?
* Precursor: tryptophan (aa)
| * Helps > 200 co-enzymes to function in body
57
What is folate's role? Who is it important for?
• RBCs
• Important for pregnant women because
helps to prevent some birth defects
• Folic acid: form found in supplements
58
What minerals are contained in meat?
* Iron (liver: richest source) • Zinc
* Copper
* Phosphorus
* Some other trace minerals
59
What increases the absorption of heme? Decreases?
* ⬆ by: vitamin C, MFP factor
| * ⬇ by: phytates, calcium, polyphenols (tannic acids), plant-proteins
60
Are minerals heat-stable? Are B vitamins easily leached into the cooking water?
Yes and yes
61
What would an individual on a vegetarian diet lack?
Protein, Iron, B vitamins
62
What does macrocytic anemia decrease? What deficiencies cause this?
- Decreased ability to synthesize DNA
| - Folate and B12 Deficiency
63
What does microcytic anemia decrease? What deficiencies cause this?
- Decreased ability to synthesize hemoglobin
- Impaired heme synthesis
- Iron deficiency
64
What do both anemias have in common?
Decreased red blood cell production
65
Name some plant-based proteins.
- Soy and soy products (tofu, tempeh)
- Meat alternatives (TVP)
- Legumes
- Whole-Grains
- Nuts
- Seeds
66
Given that the bioavailability of dietary iron is lower in vegetarians, what must you multiply the regular RDA by?
times 1.8
| ex: females: 18mg/d x 1.8 = 32 mg/d
67
Name 3 ways to increase dietary iron.
1) Cooking Method (cast iron utensils for acidic foods since Fe leeches into acidic foods)
2) Fe + Vitamin C increases absorption
3) Fish, egg, poultry, lean meats, iron-fortified vegetarian sources
68
Name 3 ways to increase vitamin B12.
1) Fortified non-dairy beverage
2) Nutritional Yeast
3) Fortified meat alternatives (TVP)
69
What does the Canadian Food Inspection Agency do? What is it mandatory for?
- Federal laws require inspection of animal carcasses to ensure safe purchasing of meat
- Mandatory for beef, pork, lamb, bison, and poultry
- -> federal and provincial
70
How is meat graded? Is it governmental?
Grading standards are set for each species separately through government consultation with each industry
71
Name the 2 factors that affect the grade of meat.
1) Quality
- > colour, grain, surface texture, fat distribution
2) Yield
- > amount of lean meat on carcass in proportion to fat, bone and other inedible parts
72
Why does marbled meat sell for higher prices?
Since it is more tender, when you cook the fat it adds more flavour and juiciness
73
What are 6 factors that affect tenderness naturally?
- Cut (more/less collagen)
- Age (at slaughter)
- Heredity and Diet
- Marbling (fat content)
- Rigor Mortis
- Aging
74
What is rigor mortis? When does it reverse?
• 6-24 hrs after • slaughter, carcass enters “stiff”
state
• Reverses naturally 1-2 d
75
What temperature are enzyme tenderizers activated?
- 55-76oC
| - Found in commercial meat tenderizers
76
Name the 2 types of meat cuts.
1) Wholesale: prior to reaching supermarket (7 primal cuts - large)
2) Retail: purchased by customer (further divided)
77
What % of meats are processed? What are the most popular?
- 1/3 of meat
| - Most popular: ham, sausage, bacon
78
Name the 4 types of processed meats.
1) Curing (salts, nitrites, nitrates)
2) Smoking (cured meat is smoked for colour, aroma, flavour)
3) Canning (pasteurization, sterilization)
4) Drying (not widely used for meets - beef jerky)
79
What happens when you cook meat at high temperatures?
Meat becomes tender when cooked due to breakdown of protein, fat, and connective tissue with increasing temperature
80
Name 4 dry-heat preparation for tender cuts.
1) Roasting (baking in oven)
2) Broiling and Grilling (based on meat thickness and distance from heat)
3) Pan-Broiling (heavy pan or flat grill with no fats/oils)
4) Frying (small cuts, low in fat, with breaded coating) (sautéing, pan-frying, deep-frying)
81
Name 4 dry-heat preparation for tender cuts.
1) Roasting (baking in oven)
2) Broiling and Grilling (based on meat thickness and distance from heat)
3) Pan-Broiling (heavy pan or flat grill with no fats/oils)
4) Frying (small cuts, low in fat, with breaded coating) (sautéing, pan-frying, deep-frying)
82
What is particular to pan broiling?
Do not add oil or water. Do not cover.
83
Name 3 moist-heat preparation for less tender cuts. What are these techniques for?
1) Braising
2) Simmering/Stewing
3) Steaming
* for heavily exercised muscles or older animals (high in connective tissue and collagen)
84
What should the internal temperature of meats be (range)?
60 to 77oC
85
How do you test for meat doneness?
Rare: shake, dangle and relax right hand
Medium: stretch out right hand and tense fingers
Well done: harden the right hand into a tight ball
86
How should you carve meat?
* Determine direction in which the muscle fibers run (grain is visible on surface)
* Cut across grain
87
How should meat be stored in the refrigerator? How long for regular meats? Variety meats?
- Change store wrapping after 2 days
- Regular: 3-5 days
- Variety: 1-2 days
88
How should meat be stored in the freezer? How long for most meats? ground beef?
- Aluminum foil, heavy plastic, freezer paper
- Most meats: 6-12 months
- Ground beef: under 3 months
89
What is important when you're wrapping meats?
Label with date, kind of meat, and number of servings or weight.
90
What shortens the sarcomere?
Actinomyosin (actin and myosin interacting with each other and forming crosslinks)
91
What is the primary protein in connective tissue? What are the other two tissue proteins?
- Collagen
| - Elastin and reticulin
92
What two factors affect the tenderness of the meat?
- Collagen (age and cut)
| - Elastin (silver skin)
93
What is silver skin?
Elastin does not soften with heating, it should be removed
| Little elastin in meats though
94
What is the protein digestibility corrected amino acid score?
(mg of limiting amino acid in 1g of test protein/mg of same amino acid in reference protein) x 100%
95
When do proteins begin to unfold in meats?
38oC
96
Which preparation techniques should you use in for older animals?
Moist-Heat preparation
97
In which direction should you cut meat? Why?
Cut across the grain
| To shorter the muscle fibres into smaller sections
98
Why is cast iron used in acidic foods?
Since Fe leeches into acidic foods
