Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Meat Science > Conversion of Muscle to Meat (Exam 4) > Flashcards

Conversion of Muscle to Meat (Exam 4) Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is homeostasis?

A

Maintenance of the physiological state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What lies under the narrow range of physiological conditions?

A

pH
Temperature
Oxygen concentration
Energy supply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What makes the beginning of postmortem changes?

A

Drop in blood pressure

Homeostatic control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are some homeostatic control mechanisms? (4)

A

Protective/survival mechanism
Increase in heart rate
Peripheral vessels constrict
50% blood remaining in vital organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When is muscle converted to meat?

A

When metabolism stops

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens when the oxygen supply is depleted?

A

TCA cycle and electron transport start failing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does homeostatic maintenance do when oxygen is depleted?

A

Shifts to anaerobic metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What accumulates when there is a decline of muscle pH?

A

Lactic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the most significant postmortem change?

A

Accumulation of lactic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the normal decline pattern of postmortem pH?

A

Gradually from 7.0 to 5.7 within 6 to 8 hours postmortem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the ultimate pH postmortem?

A

5.5 within 24 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are some factors to postmortem temperature change?

A 
Rate of metabolism (heat production)
Size and location of muscles
Predominate muscle fiber type
Duration of metabolism
Fat insulation
Slaughter: handling, stress, stun/stick
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are 2 sources of ATP postmortem?

A

Glycolytic/anaerobic metabolism

Creatine phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What sets in when ATP depletes?

A

Rigor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is rigor mortis?

A

Stiffness of death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the phases of rigor mortis?

A

Delay phase
Onset phase
Completion phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

When does the delay phase occur?

A

Immediately after exsanguination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How many actomyosin cross bridges are there during delay phase?

A

Few

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When does the onset phase occur?

A

Within hours, species-dependent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What happens during onset phase? (4)

A

Less and less phosphorylation of ADP to ATP
Sources of ATP decreased
More actomyosin cross-bridges
Gradually less extensible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the ATP supply like in the completion phase?

A

Exhausted because glycolysis stops and creatine phosphate depletes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe the completion phase.

A 
Maximum actomyosin cross-bridges
All binding sites used
Sarcomeres shortened
Muscle tension to maximum
Actomyosin bonds cannot be broken
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Look at postmortem graph

A

Look at postmortem graph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How many binding sites are used in rigor?

A

100%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How many ending sites are used in normal contraction?

A

20%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the resolution of rigor mortis?

A

Decrease in tension with time postmortem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What happens in resolution of rigor? (4)

A

Proteolytic degradation
Z disk dissolution
Loss of ultrastructural integrity
Actomyosin bonds still not broken

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

When does the most notable change occur?

A

48-72 hours postmortem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What does the most notable change cause?

A

Increased tenderness and aging effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is involved in the degradation of z disks?

A

Desmin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is involved in the decrease in passive elasticity of muscle?

A

Titin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is rigor tension?

A

Rupturing Z line/ I band junction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What happens during Z disk degradation?

A

Rigor tension

Decreases elasticity of myofibrils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What enzymatic activities cause resolution of rigor?

A

Postmortem proteolytic degradation of myofibril proteins

Calpain system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the calpain system?

A

2 calcium dependent enzymes and a specific inhibitor

36
Q

What makes up the calpaan system?

A

m-calpain
μ-calpain
Calpastatin

37
Q

What is the calpaan system activated by?

A

Ca released from mitochondria and SR during storage

38
Q

What is looked at for meat sensory quality?

A

Color
Tenderness
Juiciness
Flavor

39
Q

What is looked at for meat technological quality?

A 
Emulsifying capacity
Binding properties
Cooking loss
Cooked color
Cooked texture
40
Q

What may happen when in animal is stressed?

A

They become excited, fatigued, overheated, or chilled

41
Q

What can cause the animals to be stressed?

A

Unfamiliar environment
Being alone
Air movement, sound, space, temperature, humidity, light
Fasting

42
Q

What is stress?

A

A general expression referring to the physiological adjustments that occur during the exposure of the animal to adverse conditions

43
Q

What are the physiological adjustments that occur during stress?

A

Heart rate
Respiration rate
Body temperature
Blood pressure

44
Q

What are adverse conditions known as?

A

Stressors

45
Q

What are consequences of stress in muscle?

A

Increase demand of muscle contraction

Stress hormones help meet muscle demand

46
Q

What happens when there is an increase demand of muscle contraction?

A

Increased rate of blood flow to muscle

Impossible for the circulatory system to maintain temperature and oxygen

47
Q

What happens when stress hormones help meet muscle demand?

A

Anaerobic metabolism is favored

Accumulation of lactic acid

48
Q

What happens when there is a rapid pH decline? (6)

A 
Rapid conversion of muscle to meat
Low ultimate pH of less than 5.5
Loss of protein solubility
Loss of WHC (water holding capacity)
Increased drip loss, cooked loss
Loss of color intensity
49
Q

What is PSE? DFD?

A

Pale, soft, exudative

Dark, firm, dry

50
Q

What kind of stress is there in rapid pH decline? Species?

A

Short-term stress, few minutes before slaughter

Pig

51
Q

What kind of stress is there in slow pH decline? Species?

A

Long-term stress, at expense of glycogen storage

Ruminants

52
Q

What happens when there is a slow pH decline?

A

High ultimate pH greater than 6
Great WHC
Dry surface, sticky
Increased color intensity, dark cuts

53
Q

What is slow pH decline great for?

A

Processed meats

54
Q

what meat quality factors are looked at for pH?

A

Color
WHC
Protein functionality

55
Q

What is WHC?

A

The ability of meat to retain naturally occurring or added water during application of external forces

56
Q

What help water holding capacity?

A

Cutting
Heating
Grinding
Pressing

57
Q

What physical properties depend on WHC?

A 
Color
Texture
Firmness
Binding
pH
58
Q

What effects on processing does WHC have?

A

Technological quality (binding, emulsifying, curing, slicibility, texture)
Shrinkage
Yield

59
Q

How much of water is bound water? Immobilized water? Free water?

A

4-5%
Variable
Surface water

60
Q

What net charge do most proteins have?

A

Negative

61
Q

Wat happens with WHC as pH declines?

A

Decreasing reactive groups on proteins are available for water binding

62
Q

What happens with WHC as pH approaches isoelectric point?

A

Positive charge is similar to negative charge

63
Q

What is the isoelectric point?

A

5.0 to 5.2

64
Q

What is pH influence?

A

Net charge influence

65
Q

What does a greater pH mean for net charge and WHC?

A

More negative net charge and greater WHC

66
Q

What are 3 methods of immobilization?

A

Carbon dioxide
Electric shock
Captive bolt

67
Q

What happens to blood pressure after stunning?

A

Increases dramatically

68
Q

Why is rapid bleeding the goal?

A

To avoid blood splash

69
Q

What is the most affected place for blood splash?

A

Hind quarter

70
Q

What does lowering the carcass temperature prevent?

A

Protein degradation
Enzymatic activities
Microbial growth

71
Q

What is thaw rigor?

A

Severe rigor mortis caused by freezing muscle pre-rigor

72
Q

What is cold shortening?

A

Sudden shortening pre-rigor caused by nervous stimulation from muscle being too cold

73
Q

What is heat ring?

A

Lean carcasses not chilled properly

74
Q

How much backfat is there with heat ring in beef? Lamb?

A

Less than 0.25 in

Less tha 0.1 in

75
Q

What must the temperature of a carcass be during tiger onset?

A

15-16ºC

76
Q

What is pre-rigor deboning?

A

Cutting, deboning, and grinding immediately after slaughter

77
Q

What happens with pre-rigor deboning?

A

Glycolysis is less extensive
Greater ultimate pH of 6 to 6.7
Better WHC

78
Q

What are the key processing steps in pre-rigor deboning?

A

Salting within 2-3 hours postmortem (no rigor or protein degradation)
Rapid chilling to 2-3ºC

79
Q

What does salting within 2-3 hours do?

A

Inhibits glycolysis, preventing pH decline

Increases protein solubility and WHC

80
Q

What does electrical stimulation do?

A

Improves tenderness and meat quality

81
Q

What happens with pH and contraction with electrical stimulation?

A

Accelerated pH decline

Violent contraction

82
Q

What happens with violent contractions?

A

Rapid depletion of ATP reserves

Rapidly developed rigor mortis

83
Q

What happens in cold shortening prevention?

A

Extremely rapid glycolysis and rigor onset

84
Q

What happens in accelerated proteolysis?

A

Ca release

85
Q

What happens in physical disruption of muscle structure?

A

Extreme contractions

Meat Science (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions