2. 2
Physical Properties of Meat
1. Visual quality
2. Eating quality
3. Health quality
Influencing the purchasing
power of consumers
3. Methods used to determine water holding capacity
1. Drip loss
o an important quality characteristic for both meat industry and
consumers.
o Product weight losses is range from 1- 3%, and can be up to
10% in PSE products.
Water Holding Capacity (WHC)
o The ability of meat to retain its H2O during application of external
forces such as cutting, heating, grinding and pressing.
4. 4
Bag method
1. 20 g of muscle samples are collected, weighed individually and
recorded as initial weight (W1).
2. After weighing, samples are put in polyethylene bags then vacuum
packaged and stored in a 4ºC chiller.
3. After the completion of designated aging period, samples are removed
from the polyethylene bags, blotted gently to dry, reweighed and
recorded as W2.
4. The percentage drip loss isestimated using the following formula:
Drip loss (%) = [(W1- W2) ÷ W1] × 100
Where:
W1= initial sample weight at d 0
W2= sample weight after storage.
5. 5
Figure Image of the gravimetric method for measuring drip loss, involving suspension
of a meat sample in an inflated bag and storage at 2–4 °C for 1–2 days.
6. 2. Cooking loss
o A mixture of water and soluble substances lost from the meat
during cooking.
o Product weight losses is range from 10- 30%, and can be up
to 50% in PSE products.
7. 7
1. Samples of meat are weighed (W1), placed in polyethylene bags and
vacuum packed.
2. The samples are cooked in a pre-heated water bath set at 80 ºC for 10
min once the internal temperature of the samples is reached 78 ºC as
monitored using a stabbing temperature probe.
3. After removal of the cooked samples from the water bath and subsequent
cooling to room temperature, the samples are blotted gently dry and
reweighed (W2).
4. The percentage of cooking loss is estimated using the following formula:
Cooking loss (%) = [(W1- W2) ÷ W1] × 100
Where:
W1= initial sample weight before cooking
W2= sample weight after cooking.
8. 8
3. Centrifugation methods
A. High-speed centrifugation:
1. This involves subjecting samples of 1–20 g to centrifugal forces of 6000–
40000g for 30 min .
2. Water release is determined by weighing the water or the sample before
and after centrifugation.
3. the results obtained are influenced by the texture of the meat.
B. Low-speed centrifugation:
1. This method involves subjecting 3–15 g samples at 200–5000g for 30
min (or even longer) and measuring the weight loss of the sample or
weight of the exuded fluid.
9. 3. Other methods are as described in the following
A. Vertical drip determination
B. Vertical drip in tub
determination
10. C. Horizontal drip determination
D. Horizontal drip in filter paper
determination
11. Meat pH
o Direct measurement: muscle
pH (after slaughter) puncture
a muscle pH probe.
o In-direct measurement: (in the
lab) – 0.5 g homogenize
muscle tissue in 10ml water in
the presence of sodium
iodoacetate (to prevent further
glycolysis) then the pH is read
• The highest quality meat tend to fall in the pH range of 5.5
to 5.7. Methods used to determine pH are:
12. 12
Quality Defects
Normal range
Ruminant Poultry
PSE defect ˂5.5 ˂5.7
Normal Meat 5.3˂pH˂5.7 5.7˂pH˂6.2
DFD defect ˃6.00 ˃6.20
Table pH rating scale for ruminant and poultry meat
13. Meat color
Meat pigments
• Myoglobin (80 - 90% of the total pigment)
• Hemoglobin
Meat Myoglobin
concentration
(mg/g wet meat)
Beef 4 - 10
Veal 0.3 – 0.5
Lamb 3 - 7
Poultry 2 - 7
Dark meat
White
meat
0 - 0.5
5 g meat + 20 ml action +
4.5 DH2O + 0.5 ml HCl
Homogenization for 5 min
Filter through filter paper
read the supernatant
spectrophotometry at
640nm
Concentration of total
pigment = absorbent × 680
14. Methods used to determine color
1. Color cards :
o From pink to red
o Reference scales and influenced by lightings
15. 2. Photographic scales
o photographs of meat sample (very dark red to very pale red
or 1 to 6 scale)
17. Lightness (L) Dark (lightness<56), normal (56≤lightness≤62), and pale (lightness>62)
Redness (a*) its range: 3 to 12
Yellowness (b*) range: 0 to 13.
18. Meat texture / tenderness
1. Direct
A. Warner Bratzler shear test
B. Volodkevich method
C. Sensory analysis (taste panel)
19. Meat texture
2. Indirect
1. Myofibrillar fragmentation index (Spectrophotometer)
2. Sarcomere length (Microscope attached with camera)
3. SDS-PAGE (Protein degradation) (sodium dodecyl sulfate
polyacrylamide gel electrophoresis)
20. Current practices to improve tenderness
Tender stretch (pelvic suspension or aitch bone suspension)
Electrical stimulation
Mechanical tenderizer (blade tenderizer)
Tropical plant proteolytic enzymes (papain, bromelain, ficin)
Proteolytic enzymes, calpain proteolytic system (Ca2+
dependent system)
Calcium chloride marination/ injection / infusion
Vitamin D3 supplementation
Oral calcium supplementation
Cooking (high pressure)
