Meat Structure and Composition

Question 1

What do we consider to be the carcass?

Answer 1

The body of the animal with no blood, head, hide and digestive tract

Question 2

What are the 3 main components of meat?

Answer 2

Muscle, fat and connective tissue

Question 3

In the muscle( the lean), on average how much water, protein and fat is present in %?

Answer 3

75% Water, 19% Protein, 2.5% fat

Question 4

Unique features of muscle cells VS typical cells?

Answer 4

Muscle cell is elongated and the myofibril occupy 90% of the cell volume.

Question 5

Peri/Endo/Epimsium: What are they and what do each cover?

Answer 5

Epimysium: is the whole muscle,
Perimysium: the muscle bundle and Endomysium is the individual muscle fibre.

Question 6

A muscle cell is also called?

Answer 6

Muscle fibre, myofibre

Question 7

What is a sarcomere?

Answer 7

Is the basic contractile unit of a myocyte (muscle fibre)

Question 8

What are the main components of a myofilament?

Answer 8

Actin and Myosin

Question 9

From a chemical point of view, how is water in the muscle held?

Answer 9

The protein chains have charged hydrophilic groups (O-) that attract water (D- on the Oxygen and D- on the Hydrogen), resulting in bound, immobilised or free H2O.

Question 10

What happens to actin and myosin during relaxation and contraction?

Answer 10

During contraction the filaments slide one onto the other, while during relaxation they separate

Question 11

Describe the bands I, A and the H zone

Answer 11

I band: only the Z line in the middle, and thin actin, A band: actin+myosin+ H zone of only myosin. H zone=only myosin

Question 12

What is the difference in structure between actin and myosin?

Answer 12

myosin has a rod region (heavy chain) and a head region (light chain), it is made of 6 polipeptide chains, it has ATPase activity and binds to actin. Myosin molecules aggregate head to talk and form thick filaments. Actin is the thin filament, it is a globular and single

Question 13

What are the 3 categories of myofibrillar proteins

Answer 13

Contractile, Regulatory and Cytoskeletal

Question 14

What are the 3 categories of proteins that can be found in the muscle?

Answer 14

myofibrillar, sarcoplasmic and stromal/connective tissue

Question 15

Can you give an example of a cytoskeletal protein?

Answer 15

desmin, titin, nebulin

Question 16

Can you give and example of a connective tissue protein?

Answer 16

Collagen, elastin, keratin

Question 16

Can you give and example of a sarcoplasmic protein?

Answer 16

Myoglobin, heamoglobin, soluble proteins

Question 17

What is the difference in solubility between sarcoplasmic, myofibrillar and connective tissue proteins?

Answer 17

Sarcoplasmic: soluble in water, myofibrillar: insoluble in water but soluble in concentrated salt solutions, connective tissue: insoluble in water and dilute salt solutions, heat required to solubilise

Question 18

From the outside to the inside, what are the 3 types of visible fat in meat?

Answer 18

Subcutaneous, intermuscular and intramuscular (marbling)