Meat Color

Question 1

Define hue and chroma.

Answer 1

• Hue - wavelength

- Chroma - intensity and purity

Question 2

What are some objective measures of color?

Answer 2

• Colorimeter
• Fixed wavelength reflectance
• Video image analysis

Question 3

What are the three intrinsic factors that affect meat color?

Answer 3

Pigment concentration
* Species
* Muscle fiber type
* Animal age
Chemical state of myoglobin
* Iron oxidized or reduced
* Ligand bound to iron
* Protein in native or denatured state
Surface reflectance
* Wet meat surface reflects more light
* Dry meat surface absorbs more light - dark firm dry

Question 4

What pigments are the basis of meat color?

Answer 4

Myoglobin
* Red meat products
Hemoglobin
* Residual amount of blood left over
* Variation in pinkness of chicken meat
Cytochrome enzymes
* More predominant in muscle equipped for oxidation
* Red meat products
Astaxanthin (micro algae, krill, crustacean)
* Red/orange in seafood
* Protected in raw seafood

Question 5

What are the respective colors of meat when these three things are bound to the 6th coordination site of heme ring?

• Oxygen/carbon monoxide
• Water/nothing
• Nitric oxide

Answer 5

• Oxygen/carbon monoxide - Red
• Water/nothing - purple
• Nitric oxide - pink

Question 6

Describe the characteristics of oxymyoglobin.

Answer 6

• Bright red = REDuced
• Has a ligand on 6th = oxygen
• No packaging

Question 7

Describe the characteristics of deoxymyoglobin.

Answer 7

Deoxymyoglobin

* Reduced 
* 6th ligand - water/nothing
* Native protein - raw

Question 8

Describe the characteristics of metmyoglobin.

Answer 8

Metmyoglobin

* Oxidized
* No ligand

Question 9

If a meat product is cured, what can we assume the 6th coordination site ligand to be?

Answer 9

CO or nitric oxide (protects against oxidation)

Question 10

How does nitrite promote browning?

Answer 10

Nitrite leads to oxidation of pigment

Question 11

Why is a reducing agent added to formulations?

Answer 11

To reduce pigment back to red