Carcass and meat quality
27 important questions on Carcass and meat quality
%byproducts for chicken; cow and pig
Cow - 42%
Pig - 34%
Environmental interactions associated with meat production, the beneficial effects and negative impacts
- Increased circularity by transforming indigestible plant proteins into digestible proteins
- make use of otherwise infertile land
- production of natural fertiliser
Negative impacts
- Methane production
- Eutrophication due to N- and P-excretion
- Land use
- Water use
What can you tell about the muscle containing 75% water (65-80%)
- Partly molecularly bound
- Partly electro-statically bound to charged groups of proteins (up to 80%)
- Free water trapped within the myofibrillar network
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What is the importance of water in meat production
- Determines amount of saleable meat
- Visual retail appearance
- Important for eating quality
- Improvement of further processing yields
Chemical composition of the skeletal muscle
Proteins - 19.0%
- myofibrillar - 11.5%
- sarcoplasmatic - 5.5%
- Connective tissue - 2.0%
Carbohydrates - 1.0% (0.5-1.5%)
Minerals and vitamins - 1.5%
Muscle metabolism (ATP)
Red and white muscle fibers (3)
- Type I = SO (slow contracting, oxidative)
- Type II = FOG (fast contracting, oxidative, glycolytic)
- Type IIB = FG (fast contracting, glycolytic)
What happens in the muscle after stunning and exsanguination?
- Blood circulation and oxygen supply cease
- Muscle cells only produce ATP by anaerobic breakdown of glycogen into lactic acid
- pH falls from ±7.0 to ±5.2 (muscle dependent)
- Depletion of ATP / energy causes irreversible cross-bridges between actin and myosin, muscle becomes rigid: rigor mortis
Where is looked at for carcass quality?
- Yield
- Weight
- Lean percentage (in primal)
- Percentage of primals
- Carcass length
- Bruises
- Trim loss
How do we measure carcass quality?
- fiber optic probes
- visual / carcass conformation
Ultra sound measurements
What is Visual classification of conformation? And what are the codes?
- AA = extreme muscular
- A = good to very good musculature
- B = average musculature
- C = thin musculature
Fresh meat quality & eating quality
- Colour, colour stability
- Waterholding capacity (drip)
- Marbling, etc.
Eating quality
- Tenderness
- Juiciness
- Aroma
Suitability for further processing
Basic factors that determine meat quality
- Muscle composition
- fat / fatty acids
- collagen / binding tissue
- muscle fibre type
- pigment
- Sarcomere length
- Muscle energy store at slaughter
- glycogen content
- Muscle energy breakdown after slaughter
- rate of lactate formation
Cold shortening [sarcomere length and tenderness]
- Toughness induced by chilling meat before the onset of rigor mortis
- Occurs if muscle is cooled below 10*C before rigor is complete, i.e. Before the pH drops below 6.1
- Calcium that is stored in the muscle leaks out, when T becomes below 10*C, and when there is still glycogen/energy present the will cause extreme muscle contraction
- beef - 10 to 30 hours postmortem
- lamb - 10 to 20 hours postmortem
- pork - 1 to 8 hours postmortem
- chicken - 0.3 to 4 house postmortem
What are the major measurable meat quality parameters
- pH (early postmortem and ultimate)
- Water holding capacity (drip loss)
- Color
- Marbling (IMF)
- Shear Force (tenderness)
Colour the L* and a* value =
Redness: a* values ranging from -60 (green) to 60 (red)
IMF - NPPC Marbling Scores
Factors influencing eating quality
- Marbling (IMF)
- pHu
- Ageing
Beef tenderness determinants:
- Connective tissue
- Myofibrillar proteins
- short sarcomeres --> tough meat
- cold shortening
- tender stretching
- achilles tendon = common way
- pelvic bone (better stretch)
- Ageing
- proteolytic enzymes: calpains / cathepsins
Production chain factors on meat quality
- Farm
- genetics
- nutrition
- on-farm handling
- transport
- loading/unloading
- duration
- pre-slaughter handling
- lairage
- pre-stunning handling
What does feed withdrawal influence
- Energy store at slaughter (glocogen level, pHu)
- Dressing percentage of carcass
- Diet composition is another way to influence pHu
important pork production chain factor
From pig to carcass (some steps)
- Stun to stick interval
- Horizontal versus vertical bleeding
- Bleeding time
- Scalding temp / time or skin time
- Evisceration time
- Splitting accuracy
- etc
Keep time between sticking and chilling as short as possible
What are the effects of rapid chilling
- Less carcass shrinkage
- slower rate of pH
- less protein breakdown
- less drip loss and better color
- higher ultimate pH
- better water holding capacity / color
Why is fast chilling of beef carcasses necessary?
- To reduce microbial growth
- To improve colour stability
- To reduce development of fat rancidity
- To increase chiller capacity
- To minimize evaporative loss
However, too fast chilling of Beef/Veal/Lamb carcasses can cause cold shortening = severe toughening of the meat
What does electrical stimulation (ES) do?
- Pulses of electrical current stimulate muscle to contract
- each contraction and relaxation uses up energy and turns glycogen into lactate
- rigor is accelerated
- may enhance tenderisation during conditioning
Value of pHu - water holding capacity =
- More saleable product
- Increased premium product
- More saleable cooked product
Usefulness of DFD meat products
- Bologna tupe sausage
- cooked ham (the self life os slices is reduced)
- Cured meat cuts (Kasseler)
- Meat cuts for immediate frying or grilling
Unsuitable for
- Cured raw meat products
- Raw ham
- Leg ham
- Meat cuts packed in foils
- Fermented sausage
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