Meat Quality & Defects

How do you define meat quality?

• Appearance

  • color

  • uniformity

• Juiciness

  • Water Holding Capacity (WHC)

• Flavor

  • Amount of Fat

• Texture

  • Tenderness

  • Firmness

What are meat quality attributes most influenced by?

Postmortem muscle metabolism

• color

• water holding capacity (WHC)

• texture

Define Myoglobin

A pigmented sarcoplasmic protein that stores O2 in muscle cells

What are factors that affect meat color?

• Myoglobin content

• Chemical state of myoglobin

• Meat pH

• Water holding capacity

What happens when more of a muscle is used?

The redder it is

What more does red muscle contain?

More mitochondria and importantly more myoglobin

in regards to the chemistry of myoglobin, define Heme

Structure of iron and nitrogen and rings and double bonds

In regards to the chemistry, define Globin

Histidine is the globin portion of myoglobin

How many binding sites does iron have in regards to the chemistry of myoglobin?

six

In regards to the chemistry of myoglobin, what is the 6th iron site called? What does ti influence?

• free binding site

• Influences color

What does the denaturation of sarcoplasmic proteins do?

decreases protein functionality

What is a method to measure color in meat?

Colorimeter

Why is water holding capacity (WHC) so important?

• for processors, it affects yields

• for consumers, it affects acceptability

  • affects appearance of uncooked meat

  • affects amount of water lost before cooking

  • affects juiciness and tenderness

• for food service, it affects yield and consumer acceptability which will lead to consumer complaints

What are the water phases?

• Bound Water

  • Water molecules closely associated with muscle proteins

• Immobilized Water

  • Water attracted to bound molecules

  • processor can influence

• Free water

  • Easily separated, loosely bound

  • “Purge” drip loss, moisture lost during cooking

In regards to the water phases, when ingredients are added, what happens?

it pulls free water into immobilized state

During rigor development, what descreases?

muscle pH

What is the average chicken pH?

6.0

Below what pH will affect WHC in poultry?

5.9-5.8

What methods are there to measure WHC?

• drip loss

• cook loss

• total moisture

• expressible moisture

• sensory - juiciness

What is the frying yield?

85% Ready-to-Cook (RTC) because of fat uptake into coating

What is lost during cooking?

Water and some fat

What falls under meat texture?

• Tenderness

• Firmness

• Bind ability

• Mouth-feel

• Structure

What is meat texture influenced by?

• WHC

• Contractile state of the muscle

• State of muscle proteins in further processed products

• Meat particle size

• Connective tissue

• Fat

What are the effects on texture with increased WHC?

• increased juiciness

• firm

• tight structures

• dry,sticky texture when fresh

What are the effects on texture with decreased WHC?

• decreased juiciness

• soft

• loose structures

• wet,grainy texture

What affective testing procedures does the consumer panel do?

• a subjective method

  1. Preference

  2. Acceptance

What kind of flavor does dark meat have?

• a strong flavor

• “chicken flavor”

• more fat more solubility flavor compounds

What flavor does light meat have?

• tastes “meatier”

• Has more protein (“meat” flavor) and less fat (savory “chicken” flavor)

What is poultry meat lower in and higher in?

Poultry meat is lower in saturated fat and higher in unsaturated fat

Why does turkey oxidize quickly?

Because exposed to heat for so long during cooking

At what temperature does poultry meat freeze?

26 F

What are the carcass downgrades?

• Bruising

• Missing wing or other parts * (cannot be grade A if parts are missing)

• Miscuts

• Exposed flesh

• Broken/Disjointed bones

• Trimming (ex: breast blisters)

• Discoloration

What can happen in preslaughter handling?

• bruising

• broken bones

• dead on arrival

Bruising on wings and drumsticks make up approximately how much of bruising observed on carcasses?

60%

When do broken bones with bruises happen?

When the bird is alive

What is green muscle disease?

• Develops antemortem

• Stress from growth

• degeneration of muscle

• rapid growth squeezes tender and loses blood supply - dies

What is white striping?

• It is associated with growth: heavier broilers more affected because the muscle growing so fast it cannot put down protein, fat & connective tissue

What is wooden “woody” breast?

• Hard to the touch

• throughout the filet

• hardness observed in the live bird

• To date, much unknown about it

• looks bad, difficult to portion

• has a low WHC, does not hold marinade

When can you see wooden “woody” breast?

at 2 weeks of age

Can consumers tell wooden “woody” breast?

No because it is not tough when eaten

• it has a strange, crunchy texture but not tough

How did they find out about wooden “woody” breast?

• found out from consumer complaints in restaurants

What does wooden breast not affect?

• toughness

• cutting ability

• contractive state