Meat Flashcards
Discuss 2 techniques that can be used to overcome rigor mortis in lamb
electrical stimulation - this accelerates rigor mortis, uses up ATP and lowers pH, can be high or low voltage in improving meat tenderness
letting the lamb hang for 7 days - this results in muscle enzymes called calpains which is responsible for post-mortem tenderisation
Describe the structure of connective tissue that is present between muscle fibers in red meat. Identify the role of collagen in this structure
Epimysium surrounds the muscle fibres in read met which is the connective tissue that wrapped the muscle cell. The components of connective tissue is cells, ground substances and fibres (protein). Fascia is then a sheath of stringy connective tissue that surrounds every part of your body when it is health is provides support to joints, muscles, tendons, ligaments etc. making you more flexible as it stretches with you.
Collagen makes for tougher meat. Collagen’s role is providing structural support, maintaining muscle fibre organisation and contributing to the texture and tenderness of red meat
Is meat genetically modified?
no
when was the first shipment of frozen meat
dunedin to london 1882
what is the bovine temperature
38.5 degrees
does meat need a NIP (Nutritional Information Panel)
no
is there is more collagen in meat what does this mean
tougher cuts of meat
muscle tissue composition of red meat
Water 65%
Protein 19%
Intramuscular fat 2.5%
Other water-soluble compounds 3.5%
skeletal muscle function and structure
Function is contraction leading to movement of body parts, helps in maintaining posture, stabilises joints, maintains balance. Structure – elongated cells parallel & well organised, a little space between the cells, filled with many myofibrils (bundle of filaments)
skeletal muscles in larger animals consist of
100 um-diameter muscle fibres, each of which contains hundreds of myofibrils
How many myofibrils per a muscle fibre and what does it consist of
100s-1000, consists of linear arrays of cylindrical sarcomeres (1-2 um in diameter), the basic structural units of muscle contractions
smooth muscle function, structure
Walls of organs, stomach intestine, bladder
cardiac muscle function
found only in the heart
Muscle contraction in all muscle types result from
Interaction of myosin and actin in the muscle cell
Contracting fibres require
Continuous delivery of oxygen and nutrients via arteries
Metabolic waste is removed by
Veins and lymphatic system
How does the muscle tissue connect to blood work
One artery and one or more veins enter with nerve (neuro-vascular bundle) and branch profusely
what are axons of motor neurons
They extend from the spinal cord to the muscle. the cable transition from neurons
what is myosin
Responsible for cell movements – is a molecular motor that converts chemical energy in the form of ATP to mechanical energy – generating force of movement
what is myoglobin
A molecule is the muscle that dominantly contributes towards meat colour
difference between myosin and actin
actin is a protein that produces thin contractile filaments within muscle cells. In contrast, myosin is a protein that produces dense (thick) contractile filaments within muscle cells.
the sliding filament theory
a suggested mechanism of contraction of skeletal muscles, actin and myosin filaments to be precise, which overlap each other resulting in the shortening of the muscle fibre length. Actin (thin) filaments combined with myosin (thick filaments) conduct cellular movements.
What is adenosine triphosphate (ATP)
The source of energy for use and storage of a cellular level, ATP binding and hydrolysis needed to provide energy for contractions and needed to pump calcium out of cells for relaxation
what are 3 types of energy ATP
Phosphagen (immediate source) Anaerobic (somewhat slow, uses carbohydrates) Aerobic (slow, uses either carbohydrate or fat)
What is anaerobic metabolism
ATP production without oxygen. occurs by direct phosphate transfer from phosphorylated intermediates, such as glycolytic intermediates or creatine phosphate (CrP), to ADP forming ATP.
How to maintain ATP levels when circulation and nervous stimulation ceases
Need anaerobic metabolism – lactic acid formation - pH decreases, till glucoses runout
difference between red meat and white meat
Red fibres are for sustained action, rich in mitochondria and myoglobin, has aerobic metabolism to product ATP & carbon dioxide
White fibres for short bursts, high concentration of glycogen and glycolytic enzymes, optimised for glycolysis
what stunning technique is used before slaughter on Cows and different one for sheep
cattle - captive bolt
sheep - electrical stunning
why is blood drained out of a animal when killed
removes haemoglobin out of animal when killed
what does Rigor mortis mean
you get a huge flux of calcium ions
After death muscles and joints become stiff – actin and myosin form a complex, result of lack of ATP (can’t retrieve calcium), sarcomere length then relatively fixed (short sarcomeres {contracted muscle} usually toughens meat)
how to slow rigor mortis
Accelerated cooling with blast freezing, below 10 degrees, lowers microbial growth
what is calpains
Tenderisation of meat, activated by calcium rise (failure of pumps), activity detected 14 days after death
Components of connective tissue
Cells, ground substance, fibres (proteins)
what are Proteoglycans
Brush like structure that draws water into the tissues, to form the gel like nature of ground substance – allows tissue and fibres to slide over each other with minimal friction. Made up of proteins and polysaccharides
What is fascia
A sheath of stringy connective tissue that surrounds every part of your body when it is health is provides support to joints, muscles, tendons, ligaments etc. making you more flexible as it stretches with you
Rapid glycolysis meat colour defects
Pale soft exudative (PSE) meat results of rapid pH decline after slaughter particularly in stressed pigs
Insufficient glycolysis colour defects in meat
Dark firm and dry (DFD) meat results from low glycogen and high ultimate pH usually from starvation or stress
what is myoglobin
protein to store oxygens in the muscle cell, found in the skeletal and heart muscles
what is metmyoglobin
The state when iron has oxidised to make meat a tan brown colour
difference between grass fed and grain fed fat
grass fed - Yellow fat, darker flesh, beefy flavour
grain fed - White fat, pink flesh, buttery flavour
What is ATP + what is its role in muscle movement
ATP is produced when sugar is used to make energy as well as fats and proteins , ATP is our primary energy source
role: ATP allows for the myosin head to move into position, bind to the actin filament and pull the actin filament in (muscle contraction). Once the actin filament is in you need anther ATP to put the myosin head out and repeat the process