meat color meats exam 2

Define hue

Words we normally think of as describing color: red, purple, blue

Definitely chroma

Strength or dominance of hue

Define value

Overall intensity to how light or dark a color is

What are the instrumental measurements of color space

L*, a*, b*

Define L*

Black to white hue with high L* being white and low L* being black

Define a*

Red to green hue with high a* being red and low a* being green

Define b*

Yellow to blue hue

How is meat color impacted by age within species and how that impacts myoglobin quantity

Myoglobin loses its affinity to bind oxygen as age increases

Ex. Veal have least amount of myoglobin compared to old beef that has most amount of myoglobin

How is meat color impacted in different species at their age of slaughter

Pork- more pink, least amount of myoglobin because slaughtered at 6 months of age

Lamb- light red, middle amount of myoglobin slaughtered at 10 mo of age

Beef- cherry red, most of amount of myoglobin because it is slaughtered at 16 mo of age

Therefore white muscle fibers have pinker meat color than red as well as kess myoglobin due to being slaughtered earlier in age.

How does the type of muscle impact quantity of myoglobin in the meat

More locomotove muscles (extensor carpi radialis) use more oxygen and therefore have a higher myoglobin concentration compared to support muscles (longissimus thoracis et lumborum)

What compounds bind to the ferrous (Fe2+ covalent) state

H2O, O2, NO, CO

What color and name is myoglobin associated with when H2O is bound at the heme in the ferrous state

Deoxymyoglobin and is purple in color

What name and color is myoglobin associated with when O2 is bound at the heme in the ferrous state

Meat a red color, oxymyoglobin

What name and color is myoglobin associated with when NO is bound at the heme in the ferrous state

Cured pink meat color, nitric oxide myoglobin

What name and color is myoglobin associated with when CO is bound at the heme in the ferrous state

Red color, carboxymyoglobin

What compounds bind at the heme of myoglobin when its in the ferric state (Fe3+ ionic)

CN, OH, SH, H2O2

What name and color is myoglobin associated with when CN is bound at the heme in the ferric state

Red color, cyanmetmyoglobin

What name and color is myoglobin associated with when OH is bound at the heme in the ferric state

Brown, metmyoglobin

What name and color is myoglobin associated with when SH is bound at the heme in the ferric state

Green, sulfmyoglobin

What name and color is myoglobin associated with when H2O2 is bound at the heme in the ferric state

Green, choleglobin

What amount of atmospheric O2 is characterized with deoxymyoglobin

No O2, meat purple in color

What amount of atmospheric O2 is characterized with oxymyoglobin

Increase in PO2, bright red color

What amount of atmospheric O2 is characterized by metmyoglobin

Very low PO2, brown in color

What is metmyoglobin reducing activity (MRA)

The system in muscle that converts metmyoglobin in deoxymyoglobin and oxymyoglobin through a series of reactions until the reductants are depleted

What muscle is characterized by a high MRA

Longissimus lumborum (stays red)

What muscle is characterized by a low MRA

Psoas major (doesnt stay red)

Define oxygen consumption rate (OCR)

The respiration rate of muscles over time during display, which competes with the myoglobin for enough oxygen to keep the muscle in the oxymyoglobin state

What muscle is characterized with a high OCR

Psoas major

What muscle is characterized with a low OCR

Gluteus medius

What muscles have a higher color stability (high MRA)

longissimus lumborum

Logissimus thoracis

Semitendinosus

Tensor fasciae latae

What muscles have a very low color stability (high OCR, low MRA)

Supraspinatus

Infraspinatus

Psoas major

What are two meat color problems with cooked ground beef

Premature browning and persistent pinkness

What causes premature browning in cooked ground beef

Caused by highly oxidized meat or meat that is exposed to high oxygen atmospheres, meat will turn brown around 130 degrees fahrenheit internal temperature

What causes persistent pinkness in cooked ground beef

Caused by high pH meat, product will stau pink even with degrees of doneness that should ensure meat appropriately cooked

How does feeding livestock vitamin E affect myoglobin

Vitamin E can be fed to livestock to increase the alpha-tocopherol concentration in muscle, alpha tocopherol is an antioxidant that slow down the conversion of deoxymyoglobin or oxymyoglobin to metmyoglobin

Oxymyoglobin + oxidation + bacteria= ?

Metmyoglobin (-OH)

Metmyoglobin + bacteria=?

Choleglobin (-H2O2)

Metmyoglobin + bacteria=?

Sulfymyoglobin (-SH)

What does curing (adding nitrite) myoglobin do

Create nitric oxide myoglobin

What does heating up nitric oxide myoglobin create

Nitrosyl hemochrmogen

What advantage of vacuum packaging meat compared to retail film

Vacuum packaging ensurer barrier against oxygen while retail film is permeable to oxygen