Shared Flashcard Set

Details

Meat Colour
Following up on PSE and DFD
41
Anatomy
Undergraduate 2
04/17/2014

Additional Anatomy Flashcards

 


 

Cards

Term
What are the factors that affect the colour of meat, as seen by the consumer?
Definition
1. Viewing conditions (state of the meat, lighting)
2. Individual ability amongst humans to detect colour
3. Structure and texture of the muscle
Term
_____ is responsible for the pigment of muscles
Definition
Myoglobin (myo=muscle)
Term
What is responsible for the pigment of blood?
Definition
Hemoglobin
Term
Where is hemoglobin found, and what is it's function?
Definition
Red blood cells, for O2 and CO2 transport
Term
Where, specifically, is myoglobin found, and what is it's function?
Definition
Sarcoplasm, for storing O2 in muscle fibers
Term
What is myoglobin composed of?
Definition
Globular protein, nonprotein heme component
Term
T or F: Myoglobin is similar in size to Hemoglobin
Definition
False, hgb is 4x bigger than mgb
Term
True or False: The oxidation state of the heme ring has major influence on meat color
Definition
True! (Fe2+ ferrous vs Fe3+ ferric)
Term
How much of the total meat pigment is dependent on myoglobin, and what does it depend on?
Definition
80 to 90%, depending on hemoglobin (so, how well the animal has been bled out)
Term
T or F: Catalases & cytochrome oxidases do not contain heme units in their structure?
Definition
False, they do
Term
Which type of muscle fibers have more myoglobin? (red or white) Why?
Definition
Red, b/c involved with strong aerobic metabolism
Term
Does myoglobin content in an animal increase, or decrease with age, and why?
Definition
Increases, b/c mgb loses it's affinity for oxygen as age increases
- need higher concentration to store O2
Term
Which has a higher mgb content, locomotive muscles, or support muscles?
Definition
Locomotive, duuuh, cuz we need dat shizzz to get arooouunnd
Term
Which has the highest mgb content: Females, Intact Males, or Castrates?
Definition
Intact males (e.g. Bulls also have dark red meat)
Term
Why do game animals have more mgb than reared/domestic animals?
Definition
Because they have developed the need for more muscle content (Chicken breast vs Pigeon breast, Wild ruminants vs farm ruminants)
Term
How could diet affect meat colour?
Definition
Iron-containing diets supply Fe for mgb and hgb (e.g. veal is from calves fed only milk)
Term
What colour is myoglobin?
Definition
Purple
Term
What is the colour of fresh cut meat? Why? What contributes to this?
Definition
Purple. Because oxidized. Myoglobin, also called deoxymyoglobin
Term
What is the form of iron in uncut meat?
Definition
Ferrous (Fe2+)
Term
T or F: Ferrous iron can only react with water
Definition
true
Term
What is another name for purple mgb?
Definition
Reduced myoglobin (and ferrous)
Term
What is another name for bright red mgb?
Definition
Oxymyoglobin (ferrous)
Term
What is another name for brown mgb?
Definition
Metmyoglobin (ferric)
Term
What is Blooming, and how is it done?
Definition
Important for grading meat quality
- cut b/w 12th and 13th rib (separates hind and forequarter)
- top 2-6mm of meat reacts with O2 for 15-60 mintes
Term
What reaction occurs during blooming?
Definition
deoxymyoglobin -> oxymyoglobin
Term
T or F: O2 is conserved at high pH and temperature
Definition
False, it is used up, due to environment effects on enzyme activity
Term
If meat is kept near freezing, what effect does it have on enzyme activity, and consequently meat colour?
Definition
Enzyme activity and O2 utilization is reduced, meat is cherry red
Term
What happens when there is only a small amount of O2 available when exposed?
Definition
Fe becomes oxidized and turns brown; called metmyoglobin
Term
What is the ion reaction during the conversion of oxymygb to metmgb?
Definition
Fe2+ -> Fe3+
Term
What temperature should meat be stored at to postpone browning for 2 to 7 days?
Definition
0 to 5 degrees
Term
What happens after meat is exposed to air for 2 to 3 days?
Definition
If >20% is oxidized, sales decrease
Term
Which vitamin influences the amount of metmyoglobin in carcasses?
Definition
E
Term
T or F: There will be more light scattering AND lower pH in paler meat
Definition
True
Term
Is light scattering due to reflection or refraction?
Definition
Reflection!
Term
When a cut appears dark, is it because of Scattering, Reflectance, or Refractance?
Definition
None of these. It's due to absorption :)
Term
Paleness is caused by free _____ which is located between ____ cells
Definition
water
muscle
Term
T or F: As Free water increases, light reflectance, absorption, and color intensity all increase
Definition
True, except for absorption, it decreases
Term
DFD has ___ water holding capacity (WHC) due to ____ concentrations of intracellular water [high/low]
Definition
high, high
Term
With DFD meat, light reflection is ______ and color absorption is _______ [minimized/maximized]
Definition
minimized, maximized
Term
As WHC increases, drip loss ________
Definition
decreases
Term
What is the L-value, and how is it measured?
Definition
Lightness, with a colourimiter
Supporting users have an ad free experience!