Muscle to meat quality and quantity

Question 1

Biochemical/physical changes post mortem

Answer 1

-blood drained
-circulatory failure
-PM glycolysis - tries get energy from limited resources - last resource anaerobic glycolysis
-rigor mortis -once energy depleted muscle proteins binding
-loss of structural integrity
-change in appearance
-enzymatic degradation

Question 2

4 phases of rigor mortis

Answer 2

delay
onset
completion
resolution - muscle softens

Question 3

State and briefly describe factors effecting rigor mortis

Answer 3

-stress and disease - deplete glycogen store leads early rigor mortis high muscle PH
-chilling too quick leads to severe cold shortening - tough meat
-fibre type

Question 4

Why does PH decrease from muscle to meat ?

Answer 4

without oxygen glucose turns into lactic acid

Question 5

Which proteases are involved in progressive resolution ?

Answer 5

-calpains - inhibited by calpastatins
-cathepsins - inhibited by cystatin

Question 6

difference between tenderisation and aging

Answer 6

aging is leaving for longer

Question 7

The biochemical and physical changes behind ageing

Answer 7

-proteins broken down into amino acids and fats then aromatic fatty acids -flavour
-glutamic acid increases - flavour enhancing

Question 8

Tenderness expressed

Answer 8

-shear force
-myofibrillar fragmentation index (MFI )
-taste

Question 9

Cold shortening

Answer 9

• if temp below 10 C before rigor mortis - muscle contracts irreversible makes meat tough

Question 10

How to prevent cold shortening ?

Answer 10

beef and lamb - not below 10 in the first 10 h
pork - not below 10 in first 3h
electrical stimulation in beef and lamb ( early rigor mortis )

Question 11

The result of very rapid acidification

Answer 11

pale, soft, exudate ( PSE )

Question 12

the result of very slow acidification

Answer 12

dark, firm, dry meat ( DFD)

Question 13

TRUE/FALSE ph of meat influences how much muscle proteins charged so can gain or loose water e.g PSE

Answer 13

true

Question 14

TRUE/FALSE most proteins lose their charge between 5.1-5.5 ph and release water

Answer 14

true

Question 15

What makes meat bright red ?

Answer 15

myoglobin with oxygen

Question 16

TRUE/FALSE dark firm dry and dark cutting beef have higher water holding capacity makes turgid and reduces oxygen penetration ( not bright red )

Answer 16

true

Question 17

How can measure colour of meat ?

Answer 17

minolta colour meter

Question 18

Boar taint and how can prevent or manage ?

Answer 18

=unpleasant urine-like odour of entire boar and in some pigs

-castration
-avoid overcrowding

Question 19

Meat classification and what do letters and numbers relate to

Answer 19

rate fatness and conformation
letter -conformation
number - fat coverage