Intrinsic factors that affect meat quality (Dr Pamela) Flashcards
Name the Intrinsic factors that affect meat quality
- Muscle and muscle fibre types
- Anatomical position
- Connective tissues content:
- Carcass and muscle fat
- Juiciness
- Colour
What does tenderness include?
- Texture
- Initial ease of penetration of meat by teeth
- Ease with which meat breaks into fragments
- Amount of residue after chewing
Name the ways we can measure meat tenderness
- Blunt jaws
- Warner-Brarzler shear
- Armour-type tenderometer
- Electric meat grinder
- Instron test for tensile properies
- Meat glued onto clamp
Why do we have variation in meat tenderness?
- Exists either at slaughter
- Created during post-mortem storage
- During meat preparation
- Or a combination of the above
Texture is a function of the ordered arrangement of what?
– fasciculi (bundles of fibres)
– fibres (large cells)
– fibrils (organelles) and
– filaments (protein filaments)
Name the 3 muscle membranes?
- Epimysium
- Perimysium
- Endomysium
Define Epimysium
Connective tissue that surrounds the entire muscle
Define Perimysium
Layer beneath epimysium, divides the muscle fibers into small groups, or fasciculi. Primary bundles, secondary bundles and tertiary bundles
Define Endomysium
Layer beneath perimysium, surrounds muscle fibers individually.
What factors influence the size of fasciculi?
- Muscles engaged in lighter activities
- Muscle for finely adjusted movements (eye muscle)
- Muscle performing grosser movements (Biceps)
What is the smallest contractile elements of muscle?
Sarcomeres
What is the fluid surrounding the sarcomeres called?
Sarcoplasm
What does the Sarcoplasm contain?
- Sarcoplasmic proteins
- Glycolytic enzymes
- Proteolytic enzymes
- Cell elements
What factors determines the diameter of muscle fiber?
– Age
– Plane of nutrition
– Degree of post-natal development
– Oestradiol administration
What is a Sarcolemma?
Excitable membrane that contains electric (voltage) gated channels
Extends into cell to form transverse tubules, or T-tubules
What is the physical properties of Sarcoplasmic reticulum (SR)
- Modified endoplasmic reticulum
- Network of horizontal tubules
- Wrap around the myofibrils
- Fuse at each end to form a vertical tubule called the terminal cisterna
What is the function of Sarcoplasmic reticulum (SR)?
Regulates ionic calcium by ATP calcium ion pumps
What does the thin Actin filaments of myofibrils consist of?
- Actin protein
- Associated protein troponin
- Associated protein tropomyosin
What does the thick Myosin filaments of Myofibrils consist of?
molecules of myosin containing a head (cross-bridge) region and tail region
What is the function of Myosin?
Myosin binds ATP that serves as energy for movement of cross-bridge which results in shortening of sarcomere (muscle contraction)
Name the different transverse structures of myofibril
- A-bands
- H-bands
- M-line
- I-bands
- Sarcomere
Define A-bands
Dark regions consisting mostly of the thick filaments and the overlapping portions of the thin filaments
Define H-bands
Light region in middle of A-band
Define M-line
Line in middle of H-zone
Define I-bands
Light regions consisting mostly of the thin filaments and their associated Z-discs
Define Sarcomere
Region of the myofibril which is defined as the unit of contraction. Region from middle of each I-band, the Z-discs (lines) to next Z-disc; thus includes an A-Band
What does the Neuromuscular Junction (Synapse) consist of?
A. Axon terminals
B. Synaptic cleft
C. Motor end plate
