Meat science Test 2 Flashcards
1
Q
Osteo
A
bone
2
Q
myo
A
muscle
3
Q
sarco
A
flesh or meat
4
Q
epi
A
on, upon, above
5
Q
peri
A
enclosing, surround, near
6
Q
endo
A
within, inner
7
Q
Types of tissue found in meat
A
epithelium
nervous
connective tissues - adipose fat, bone, cartilage
muscle
8
Q
epithelium
A
thin layer that covers all free surfaces of the body - includes skin and gastrointestional tract
contains secretory cells - mucous, sweat, enzymes, etc.
9
Q
nervous tissue
A
made of neron and glial cells and functions to transmit electrical impulses throughout the body
neuron - nerve cells
glial cell - support cell that help insulate and support the nerve cell
10
Q
Connective tissue
A
provides the structual framework of an animal
epimysium, perimysium, endomysium
11
Q
epimysium
A
surrounds the entire muscle
fibrous tissue surrounds the entire muscle, prevents friction
12
Q
perimysium
A
surrounds the muscle bundle and is where marbling is located
13
Q
endomysium
A
surrounds the myofiber (muscle cell)
14
Q
adipose tissue
A
type of loose connective tissues - the most common found in vertebrates
stored energy
cushions organs
insulates the body
found as - mesentric (internal fat), subcutaneous (external fat), intramuscular (fat within the muscle), and intermuscular (fat between the muscle)
15
Q
bone
A
dense connective tissue - provides structural support, enables mobility, produce red and white blood cells, storage for minerals
16
Q
cells of the bone
A
osteoblasts
osteocytes
osteoclasts
17
Q
osteoblasts
A
produces the matrix for formation and mineralization of bone, cannot act indivdually musct be grouped
18
Q
osteocytes
A
found in mature bone tissue when osteoblasts become entrapped in thier tissue matrix they become osteocytes
19
Q
osteoclasts
A
breaks down bone tissue to release minerals into the blood stream
20
Q
cartiliage
A
firm, resilient, white and flexable connective tissue - reduces in amount as the animal ages, found at the ends of long bones at the joint, does not contain blood or nerves
specialized cells - chondrocytes - produce collagenous ectracellular material
21
Q
collagen
A
the most abundant protien found in animals
located in the skin and extracellular space in the body
used for cosmetics and surgical materials
most prominent amino acid in collagen is glycine
22
Q
cartilage types
A
elastic cartilage - yellow carilage (ear, epiglottis)
hyaline cartilage - translucent or glass-like cartilage, pearl-grey in color (joint)
fibrocartilage - mixture of cartilaginous tissue, soft tissue-bone junctions (pubic symphysis, discs between vertebrae)
23
Q
muscle tissue
A
skeletal - striated and voluntary
cardiac - striated and involuntary
smooth - not striated and involuntary
24
Q
striations are caused by
A
cells
25
muscle is ____ water
75%
26
skeletal
striated and voluntary
primary muscle type for meat
multinucleated with nuclei locate toward the edge of the cell
cannot replicate once formed
27
cardiac
striated and involuntary
single centrally located nucleus
varying lenghts of the thin filament
28
smooth
not striated and involuntary
mononucleated, with nucleus in the middle of the cell
tight membrane to membrane junctions for communication between cells
29
myofiber
muscle fiber/cell
30
myofibril
contractile apparatus primarily made from actin and myosin
think little
31
sarcolemma
membrane surrounding the myofiber
32
sarcomere
smallest contractile unit of myofibril
33
sarcoplasmic reticulum
muscle equivalent of the endoplasmic reticulum
binds Ca needed for contraction
Ca spongs-holds until needed
34
The longer the sarcamere the _________________________________
more tender the muscle and vise versa
35
A band
darker in color; runs the lenght of thick filament
36
I band
lighter in color; only thin filament present
37
H zone
only thick filament present
38
Z line (disk)
End of the sarcomere where the thin filament is anchored
39
M line
middle of the sarcomere where thick filament is anchored
40
thick filament
primarily myosin
organized bi-directional from the M-line
41
thin filament
primarily actin - G-actin (globular) polymerizes with other G-actin to form F-actin (filamentous)
Tropomyosin and troponin act as regulatory protiens
42
Titan
important for myofibril assembly and muscle elasticity
one titan molecule runs half the lenght of the sarcomere
one of the largest known protiens
43
Nebulin
acts as a molecular ruler for length of thin filament
anchored into the Z line
44
in order to contract
need all myosin heads to "pull"
45
sarcoplasmic reticulum releases what and is stimulated by what
storage of calcium ions to be released when stimulated by an impulse
T-Tubules - surround the myofibrils and assit in delivering ions
46
nerve stimulation
transmit stimuli to skeletal muscle along motor nerves
myelinated nerve fibvers conduct stimuli 30-40 times faster than unmyelinated nerves
47
myoneural junction
where the terminal endings of nerves and the sarcolemma of muscle cells meet
motor end plate - surface of the muscle fiber where it meets the terminal end of a motor nerve
48
Muscle contraction - major players
contractile players - actin and myosin
regulatory protiens - tropomyosin and troponin
49
actin
thin filament; pulled toward M line
50
myosin
thick filament; myosin heads pulls actin toward the M line, but does not move itself
51
tropomyosin
rope
fits in groove formed in F-actin
along with troponin-I covers the myosin binding site on actin
52
Troponin
I - physically inhibits myosin binding
C - binds calcium ions for contraction
T - binds tropomyosin
53
relaxation and contraction phases
ATP bound to myosin head; tropomyosin blocking myosin - relaxation
ATP hydrolyzed to ADP; troponin requires Ca; tropomyosin removes block
Crossbridge formed; power stroke phase - contraction
ADP replaced with new ATP; crossbridge released; tropomyosin blocking myosin - relaxation
54
sources of energy
ATP
Creatine/phosphocreatine
ADP + phophocreatine = ATP + creatine
Glucose - from glycogen breakdown, from blood
55
Antimortem metabolism
aerobic
37 ATP
56
postmortem metabolism
anaerobic
3 ATP
57
lactic acid breakdown
when alive = body will get rid of lactic acid
when dead = whatever is in muscle stays
58
Muscle fiber types
red vs. white
slow twitch vs. fast twitch
type I vs. type II
not every muscle has 1 fiber type - can be a combination
59
red vs. white
visual discription
determined by the amount of myoglobin
red = more myoglobin
60
slow twitch vs. fast twitch
red - slow
white - fast
force and how fast contraction
fast = sprinter
slow = marathon runner
61
Type I vs. type II
red (type I)
white (type II)
62
red fiber
mitochondrial activity, high oxygen, slow to fatique, less power and strength
63
white fiber
glycoysis activity, low oxygen, quick to fatique, more power and strength
64
Homeostasis
ability of an organism to maintain internal equilibrium by adjusting physiological processes
the body will adjust it physiological processes in order to survive
65
immobilization
renders the animal unconscious
want to do it quickly and gently - excessive struggling or nerve stimulation can result in poor quality
kosher and halal animals are not immobilized
66
exsanguination
removal of blood
homeostastic regulation - body senses loss of blood pressure, body increases heart rate and constricts blood vessels to counteract loss in BP, about 50% of blood can be removed from body while remainder is in vital organs
67
If lactic acid is in the body, then it will cause a decrease in
pH
68
combination of high heat and low pH negatively affects ______________
meat quality
denaturing protiens - lose free charges, and no longer able to hold water
69
rigor mortis
latin for "stiffness of death"
result of actomyosin crossbridges
irreversible muscle contraction
70
Phases of rigor mortis
delay
onset
completion
resolution
71
delay phase
period after death where muscle is relatively extensible (elastic/moveable)
still plenty of ATP available, but creatine and primarily glycogen are being used
not visible
72
onset phase
muscle begins to lose extensibility
ATP reserves beginning to be used up
some actomyosin crossbridges are being permanently formed
73
completion phase
muscle is relatively inextensible (stiff)
all ATP reserves are used up
actomyosin crossbridges are formed and cannot be broken
74
resolution phase
tension on muscles is lessened
not true resolution, actomyosin crossbridges still formed
decrease in tension due to enzymatic breakdown of the sarcomere
75
aging
hold carcasses for extended periods of time at refrigerated temperatures
76
proteolytic enzymes
calpains
caspases
cathepsins
77
calpains
most common
activacted by calcium
thought to be responsible for the majority of postmaortem tenderization
found in papaya
78
caspases
enzymes responsible for apoptosis (programmed cell death)
79
cathepsins
present in the lysosomes
activated by low pH
80
Physcial changes in muscle
Muscle color - changes to a dark purple color, when cut during fabrication the exposed tissue will "bloom" into a bright cherry red
Muscle firmness - degredation
water holding capacity
81
Factors affecting postmortem changes and meat quality - key factors
pre-slaughter management
immobilization
exsanguination
heat buildup
loss of energy sources
lactic acid buildup
rigor
postmortem storage
82
antemortem effects
stress - physiological adjustments during exposure to adverse conditions
heart rate
respiration rate
body temperature
blood pressure
83
potential stressors
sorting
loading into trucks
weighing
driving
immobilization
84
stress susceptible
high temperature
rapid glycolosis
early onset of rigor
85
postmortem pH decline determined by:
amount of glycogen
speed of glycolysis
water holding capacity
color
protien denaturation
protease activity (tenderness)
lipid oxidation during storage (spoilage)
flavor
cure reaction in processed meats
86
PSE
pale, soft, and exudative
plae/light in color
soft to the touch
poor water holding capacity
reduced juiceness
lower processing yeild
increased cook loss
87
DFD
dark, firm, and dry
darker in color
firm/sticky to the touch
excellent water holding capacity
will not bloom when exposed to oxygen
excellent conditions for bacterial growth
poor shelf life
88
water holding capacity
isoelectric point (pI) of meat is pH ~ 5.2
as the pH approaches the pI less water binds to the myofibrils
additionally, the myfibril will shrink in size due to lack of water and charges to push protiens apart
89
protien denaturation
can result from combination of high temperature and low pH seen early [ostmortem
90
with a low pH the product tends to have a ____________ flavor
tangy or sour
91
rendement naple (RN) gene
increased muscle glycogen
92
halothane gene
deformed ryanodine receptor - leek calcium
93
myoglobin
an iron and oxygen binding protien found in the muscle tissue that is responsible for meat color
94
as animals increase in age there is an increase in
myoglobin content
amount of connective tissue
meat flavor - less palatable
95
high levels of ______________ can cause fat to yellow
beta-carotene
can be fixed by providing grain diet for 105 days
96
high levels of vitamin E prior to slaughter ---------->
improves self life as vitamin E is an antioxidant
97
cold shortening
shortening that occurs when muscle is chilled to below 15-16 degrees C prior to onset of rigor
related to either the release of calcium or a failure of the calcium pump of the sarcoplasmic reticulum
98
thaw rigor
shortening that occurs when muscle that was frozen pre-rigor is thawed
formation of ice crystals within the muscle cell
these crystals can burst the sarcoplasmic reticulum and release large amounts of calcium
99
electrical stimulation
prevents cold shortening by accelerating glycolosis and onset of rigor
accelerates proteolytic activity through enhanced calcium release
physical disruption of muscle fibers
100
pre-slaughter handling
animals are held off food for 24 hours prior to slaughter
aloowed access to free water
101
pork slaughter stunning
electrical stunning
occurs on either side of the occipital condyles - behind each ear
normal stun settings are 70-90 volts and 0.3 amps for 2-10 seconds
102
exsanguination
knife is inserted toward the tail at the point of the sternum
the stick hole should be no wider than the knife blade to avoid contaimination during scalding
103
scalding
water temperature is approximately 140F
scald time should be 4-41/2 minutes or when the hair slips easily from the skin
soft - feb to march
hard - sep to nov
104
dehairing
carcass is transferred to a dehairing machine to remove the majority of hair
additional hair is removed using bell scapers and torches to singe hair
105
toenail removal
toenails are removed from both the front and hind limbs
DO NOT hold the leg with your non-pulling hand
106
loosening the tendons
the tendon for hanging the carcass is located between the dewclaws on the hind leg
107
Pigs have the highest dressing percentage due to
skin and toes
108
USDA grades for pork carcasses
US No. 1 - highest cutability
US NO. 2
US NO. 3
US NO. 4
US utility - unacceptable - pse
109
quality is best evaluated at the
10th rib
110
pork carcass grade
(4 * last rib thickness, inches) - (1 * muscling score)
111
Muscle score
3 = thick
2 = average
1 = thin
112
pork 4 lean primals
ham
loin
picnic shoulder
boston butt
113
beef major primals
round
loin
rib
chuck
114
where does bacon come from
belly of pig
115
what is the pluck
trachea
heart
lungs
116
removal of the head
between the occipital condyles and atlas vertebra
