Exam 3 Meat to Muscle

Question 1

homestasis

Answer 1

• maintenance of a physiologically balanced internal environment
• blood pressure
• oxygen concentration
• energy supply
• temperature
• pH

Question 2

blood pressure post mortem

Answer 2

vaso contractor (reduced diameter of blood vessel)

Question 3

oxygen concentration post mortem

Answer 3

oxygen supply declines so body trys to use up only remaining supply from myoglobin

Question 4

energy supply post mortem

Answer 4

• declines

- only 2 ATP produced

Question 5

temperature post mortem

Answer 5

temp declines

Question 6

pH post mortem

Answer 6

when lactic acid accumulates it goes from 7 (living) to 5 (post mortem)

Question 7

onset of rigor mortis

Answer 7

• stiffness follows removal of blood and oxygen

- muscles stiffen bc ATP isn’t produced and actin and myosin bond together 100%

Question 8

rapid metabolism post mortem

Answer 8

• slower chill after death
• caused by more heat from faster/ rapid muscle metabolism
• faster pH decline

Question 9

normal muscle metabolism post mortem

Answer 9

• normal/faster chilling after death
• leads to more tender meat
• more ATP
• reduced bacterial accumulation
• more efficient

Question 10

anaerobic muscle metabolism

Answer 10

• no oxygen
• fast twitch fibers
• pyruvate
• lactic acid build up
• 2 ATP
• higher pH

Question 11

aerobic muscle metabolism

Answer 11

• oxygen
• slow twitch fibers
• pyruvate
• TCA cycle
• 34 ATP

Question 12

when the muscle stops receiving blood, oxygen is no longer present and _________ metabolism begins

Answer 12

anaerobic

Question 13

glycogenolysis

Answer 13

-glucose molecules are cleaved from glycogen/ breakdown of glycogen to glucose

Question 14

glycolysis

Answer 14

• glucose goes through 10 reactions

- results in 2 pyruvate

Question 15

pH change before and after death

Answer 15

• living muscles: 7.2
• 12-24 hours after death: 5.3 - 5.8
• inosine to hypoxanthine

Question 16

substances with high amounts of H+ following death

Answer 16

• low pH (more acidic)

- pH = -log [H+]

Question 17

r-value

Answer 17

concentration of inosine divided by concentration of adenosine

• indirect measurement of ATP status
• breakdown of ATP = higher r-value

Question 18

gravimetric fragmentation

Answer 18

• weight of meat left over on the top of the screen

- smaller number = more tender

Question 19

factors influencing pH drop

Answer 19

• gegentics/ muscle fiber type
• stress (body temp, respiration, blood pressure)
• amount of glycogen present
• postmorte temperature/ cooling rate

Question 20

fast-twitch fibers

Answer 20

produce more lactic acid bc amount lactic acid is directly proportional to amount of carbohydrates broken down for fuel

Question 21

post rigor muscle

Answer 21

• stiff
• actin and myosin is tightly connected
• chill boned muscle

Question 22

pre rigor muscle

Answer 22

• still flexible
• water bound in expanded spaces between myosin and actin
• hot boned muscle

Question 23

5 batter preparations

Answer 23

• cold boned/ traditionally minced
• hot boned/ warm minced with no chill
• hot boned/ chill minced with CO2
• hot boned/ chill minced after crust-freeze-air-chill
• hot boned/ chill minced after 1/4 section/crust-free-air chill

Question 24

caudal

Answer 24

• sarcomere length

- longer sarcomere length = more tender

Question 25

medial

Answer 25

- pH | - r-value

Question 26

cranial

Answer 26

gravimetric fragmentation index

Question 27

3 types of protein

Answer 27

- myofibrilliar (contractile element proteins) - sarcoplasmic (metabolic proteins) - stromal (connective tissue proteins)

Question 28

myofibrilliar proteins

Answer 28

- contractile element proteins - 9.5%, 50-55% - salt soluble - ex. myosin, actin, troponin, titin

Question 29

sarcoplasmic proteins

Answer 29

- metabolic proteins - 6%, 30-35% - ex. water enzymes, myoglobin

Question 30

stromal proteins

Answer 30

- connective tissue proteins - 3%, 15-18% - non-soluble - ex. collagen, reticulum

Question 31

PSE

Answer 31

- pale, soft, exudative | - glycogen used up during stress and lactic acid builds up

Question 32

what animals are prone to stress

Answer 32

swine and turkey

Question 33

PSE meat qualities

Answer 33

- low pH - low water holding capacity - less valuable - reduced consumer acceptability/palatability of fresh meat

Question 34

DFD

Answer 34

- dark, firm, dry - from little glycogen remaining for anaerobic metabolism - higher pH and water holding capacity - caused by long term stress, fatigue, exercise, fasting, excitement, fighting - in beef and swine

Question 35

DFD pH after 12-24 hours

Answer 35

6.4 (normal is 5.5 after 12-24 hours)

Question 36

PSE pH after 30 min

Answer 36

5.5

Question 37

least water holding capacity pH

Answer 37

5.5

Question 38

DFD meat qualities

Answer 38

- high moisture/ water holding capacity - juicy fresh meat - bad for producing dry products - metallic taste - environment for microbial growth

Question 39

order of rigor mortis graph

Answer 39

- delay (still have ATP) - onset - completion (almost top) - resolution (right before declining)

Question 40

beef and lamb time of rigor onset

Answer 40

6-12 hours

Question 41

pork time of rigor onset

Answer 41

1/4 - 3 hours

Question 42

turkey time of rigor onset

Answer 42

less than 1 hour

Question 43

chicken time of rigor onset

Answer 43

less than 30 min

Question 44

cold shortening

Answer 44

- cooling occurs too quickly - carcass is too lean - rapid release of calcium (gets tougher faster/ increased rigor development) - issue of hot-boning carcass

Question 45

thaw rigor

Answer 45

- muscle is frozen (with liquid nitrogen) pre-rigor and thawed - calcium floods muscle from sarcoplasmic reticulum - results in 66% shortening - severe toughening and release of water - like sponge- squeezes all not bound water out

Question 46

3 states of water

Answer 46

- bound - immobilized - free

Question 47

bound water

Answer 47

- 4-5% of total 76% | - not released during processing except ashing

Question 48

immobilized water

Answer 48

- 16-17% of total 76% - create multilayers of water looser farther from bound water) - some lost during cooking

Question 49

free water

Answer 49

- 79% of total 76% | - lost as purge or drip during cooking