Meat 1

Question 1

What are the three kinds of tissue that compose each muscle?

Answer 1

Muscle tissue, connective tissue, and adipose tissue (fat)

Question 2

What are the percentages of muscle tissue composition?

Answer 2

75% water
18% protein
4-10% fat
<1% glycogen
some vitamins & minerals

Question 3

What are the primary contractile proteins in muscle tissue responsible for movement?

Answer 3

Actin (thin filament) & Myosin (thick filament)

Question 4

What are the types of muscle fibers?

Answer 4

-Slow twitch (red) (developed tissue)
-Fast twitch (white) (little-used tissue)

Question 5

Slow-twitch muscle fibers are adapted for what type of energy expenditure?

Answer 5

Long, sustained energy (lots of oxygen required)

Question 6

What is the primary energy source for slow-twitch (red) muscle fibers?

Answer 6

fat

Question 7

What pigment gives slow-twitch muscle fibers their characteristic red color?

Answer 7

Myoglobin

Question 8

Fast-twitch muscle fibers are adapted for what type of energy expenditure?

Answer 8

Short bursts of energy (less oxygen required)

Question 9

What is the primary energy source for fast-twitch (white) muscle fibers?

Answer 9

Carbohydrates (Glycogen)

Question 10

What is the most abundant fibrous protein in muscle connective tissue?

Answer 10

Collagen (holds muscle together, white in color)

Question 11

What yellow-colored connective tissue protein is found primarily outside the muscle and is resistant to chemical change?

Answer 11

Elastin

Question 12

The protein matrix in which collagen and elastin are held is known as what?

Answer 12

Ground Substance

Question 13

What fibrous protein in connective tissue is linked to a saturated fatty acid?

Answer 13

Reticulin

Question 14

What is the basic component in collagen and what does it do?

Answer 14

Tropocollagen (3 strands that twist and bind).
As an animal matures, there is additional bonding, then crosslinking, making the meat stronger & eventually tougher.

Question 15

What happens to collagen when it is heated in the presence of water?

Answer 15

gelatin

Question 16

What is Tenderness in meat?

Answer 16

The ease with which meat can be cut or chewed.

Question 17

How does an increase in collagen affect the tenderness of meat?

Answer 17

An increase in collagen makes it LESS tender, which is a tougher texture and makes it harder to chew

Question 18

How does fat contribute to the perception of tenderness in meat?

Answer 18

As it melts, fat disrupts connective tissue and increases juiciness, which gives the perception of tenderness.

Question 19

What is Juiciness in meat?

Answer 19

The moisture content perceived when eating meat.

Question 20

What type of fat, also known as marbling, increases the juiciness of meat when it melts?

Answer 20

Intramuscular fat

Question 21

How does the structure of muscle change as an animal ages (including humans)?

Answer 21

Muscle fibers increase in diameter, and there is an increase in connective tissue and crosslinking. (Fat may also increase)

Question 22

What are the two primary heme-containing pigments found in meat?

Answer 22

Hemoglobin & Myoglobin

Question 23

What is the primary function of hemoglobin in the body?

Answer 23

Transports oxygen throughout blood

Question 24

What is the primary function of myoglobin in the body?

Answer 24

It receives oxygen from the blood and stores it in the muscles.

Question 25

Which pigment is predominantly responsible for the color of meat, accounting for about 75%?

Answer 25

Myoglobin

Question 26

What factor within the myoglobin molecule determines the color of the meat?

Answer 26

The oxidation state of the iron (Fe) atom.

Question 27

What is the name of the pigment in fresh meat protected from air, which has a purple-red color?

Answer 27

Myoglobin in its native state

Question 28

What is the iron state in myoglobin (purple-red pigment)?

Answer 28

Fe2+ (ferrous iron).

Question 29

When meat is exposed to oxygen, myoglobin binds with it to form what cherry-red pigment?

Answer 29

Oxymyoglobin

Question 30

What is the iron state in oxymyoglobin (cherry-red pigment)?

Answer 30

Fe2+ (ferrous iron).

Question 31

Often during storage, with limited oxygen and light exposure, myoglobin can oxidize to form what brownish-red pigment?

Answer 31

Metmyoglobin

Question 32

What is the iron state in metmyoglobin (brownish-red pigment)?

Answer 32

Fe3+ (ferric iron).

Question 33

What is the effect of heat on myoglobin?

Answer 33

1. Turns to Oxymyoglobin 2. Denatured globin hemichrome aka denatured metmyoglobin (gray-brown)

Question 34

What is the iron state in denatured globin hemichrome (cooked meat pigment)?

Answer 34

Fe3+ (ferric iron).

Question 35

What is the name of the stable pink pigment formed in meat cured with nitrates or nitrites?

Answer 35

Nitrosyl-hemochrome.

Question 36

What is the iron state in **nitrosyl-hemochrome** (cured meat pigment)?

Answer 36

Fe2+ (ferrous iron).

Question 37

What are two primary purposes for adding nitrates/nitrites to meat during the curing process?

Answer 37

Flavor and preservation (killing bacteria like botulism).

Question 38

When cured meat pigment (nitrosyl-hemochrome) is exposed to light and air, it oxidizes and turns what color?

Answer 38

A fluorescent green color.

Question 39

What causes seafood to become more opaque when it is cooked?

Answer 39

The coagulation of proteins.

Question 40

What specific *carotenoid* pigment is responsible for the red color of cooked crustaceans like shrimp and lobster?

Answer 40

Astaxanthin. (original pigment is denatured and loses its color)

Question 41

The color of salmon meat comes from what type of pigments acquired through their diet?

Answer 41

Carotenoids

Question 42

Why is the flesh of white fish, like cod, pale in color?

Answer 42

They move less and their muscles are less vascularized, resulting in lower levels of myoglobin.

Question 43

Which organ meat is an exceptionally rich source of Vitamin A?

Answer 43

Liver

Question 44

Besides B vitamins and various minerals (zinc, copper, phosphorus), what two types of meat are mentioned as great sources of iron?

Answer 44

Beef and mollusks.

Question 45

Why is Tuna's meat dark red in color?

Answer 45

Highly vascularized. Slow-twitch. Constant swimming in open water; large amount of red muscle.

Question 46

Where is Hemoglobin found?

Answer 46

In red blood cells

Question 47

What does Hemoglobin look like?

Answer 47

A 4 heme-polypeptide & very large

Question 48

Where is Myoglobin found?

Answer 48

In muscles

Question 49

What does Myoglobin look like?

Answer 49

A 1 heme-polypeptide, type of muscle fiber determines the amount.

Question 50

Compare muscles in which fast twitch fibers are predominant to those in which slow fibers dominate. Give examples from animals.

Answer 50

Fast twitch: Chicken breast. used for short bursts of flight and mostly white muscle. Slow twitch: migratory bird flight muscles, like a goose. Designed for long-distance sustained flight. Richly vascularized and dark red.

Question 51

What are the four types of protein in connective tissue?

Answer 51

1. Reticulin 2. Elastin 3. Collagen 4. Ground Substance

Question 52

What are the 3 types of fat found in meat?

Answer 52

1. Intramuscular 2. Intermuscular 3. Subcutaneous