Meat Color (Exam 4)

Question 1

If there is more myoglobin, what is the color of meat like?

Answer 1

Darker

Question 2

What is myoglobin?

Answer 2

Water soluble globular protein

Question 3

What are the 8 α-helices in myoglobin?

Answer 3

A, B, C, D, E, F, G, H

Question 4

What is within the 8 α-helices in myoglobin?

Answer 4

Heme rings

Question 5

What is the structure of heme rings?

Answer 5

4 pyrrole ring structure

Iron atom at the center

Question 6

How many iron binging site does myoglobin have? Where are they?

Answer 6

6
4 bonded to heme ring
1 bonded to proximal HIS-93
1 bonded to ligands

Question 7

Look at chart on slide 11

Answer 7

Look at chart on slide 11

Question 8

What are the 2 oxidation states of iron?

Answer 8

Ferrous

Ferric

Question 9

What happens when there is ligated iron and meat color: Mb/DMb (water added)?

Answer 9

Ferrous for heme Fe

Question 10

Why does stuff happen when there is ligated iron and meat color: Mb/DMb (water added)?

Answer 10

Very low O2

Only water to bond

Question 11

Where do reactions happen when there is ligated iron and meat color: Mb/DMb (water added)?

Answer 11

Uncut or vacuum-packaged meat

Question 12

What color is meat when there is ligated iron and meat color: Mb/DMb (water added)?

Answer 12

Purplish-red or purplish-pink

Question 13

What happens when there is ligated iron and meat color: OMb (oxygen added)?

Answer 13

Ferrous for heme Fe

Question 14

Why does stuff happen when there is ligated iron and meat color: OMb (oxygen added)?

Answer 14

Exposed to oxygen or air
At least 40 torr of O2
1 binding site occupied by diatomic oxygen
Distal histidine stabilizes Fe-O2 bond

Question 15

Where do reactions happen when there is ligated iron and meat color: OMb (O2 added)?

Answer 15

Blooming meat cute

Over-wrapped, Hi-Ox MAP

Question 16

What color is meat when there is ligated iron and meat color: OMb (O2 added)?

Answer 16

Purplish-red or purplish-pink

Question 17

What happens when there is ligated iron and meat color: MMb (OH added)?

Answer 17

Ferric for heme Fe

Question 18

Why does stuff happen when there is ligated iron and meat color: MMb (OH added)?

Answer 18

Low O2
Low MRA
Low O2 transmission rates

Question 19

Where do reactions happen when there is ligated iron and meat color: MMb (OH added)?

Answer 19

Oxidized meat cuts prolonged exposure to O2

Deep layer of Omb without enough O2

Question 20

What color is meat when there is ligated iron and meat color: MMb (OH added)?

Answer 20

Brown

Question 21

What is activated when SH is added?

Answer 21

Sulfmyoglobin

Question 22

What is the order of meat color changes?

Answer 22

Red to pink to tan to brown

Question 23

What are remedies to preservation?

Answer 23

Feed supplement (vitamin E)
Preservaitves sprayed
Active packaging