MEAT SCIENCE EXAM 2

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Gases used in MAP packaging

“High Oxygen – 80% oxygen, 20% carbon dioxide”

“Carbon Monoxide – 0.4% carbon monoxide, 30% carbon dioxide, 69.6% nitrogen”

Antioxidants used to preserve meat color

Vitamin E and Resveratrol

Vitamin E – Prevents ______, slows conversion of myoglobin to metmyoglobin

oxidation

“Resveratrol –________… provides antioxidant and anti-inflammatory benefits”

an extract of grape

Protein responsible for meat color

MYOGLOBIN

Breakdown of lipids (3 steps)

1. Initiation

2. “Propagation

3. “Termination

Initiation –

abstraction of a hydrogen from a fatty acid… forming a fatty acid radical”

Propagation

fatty acid radicals continue to make more fatty acid radicals

Termination

there is nothing left to oxidize

Myoglobin states

Deoxymyoglobin

Oxymyoglobin

Metmyoglobin

Deoxymyoglobin

• PURPLE

• “No ligand”

• Ferrous (Fe²⁺)

Oxymyoglobin

• Bright red”

• “Oxygen bound”

• Ferrous (Fe²⁺)

Metmyoglobin

• “Brown”

• “H₂O bound”

• Ferric (Fe³⁺)

Palatability factors

1. Tenderness

2. Flavor

3. Juiciness

5 basic tastes

Salty,

sweet,

bitter,

sour,

umami

3 components of flavor

• Taste

• “Aroma

• “Trigeminal sensory system

Taste

five basic tastes

Aroma

combination of taste and smell

Trigeminal sensory system

detects irritants in the throat and nose

Why meat turns brown during cooking

When myoglobin is heated, it denatures

When peak tenderness is achieved

Postmortem aging – enzymes

_______ “increase over time to allow for degradation of structural proteins”

Calpains

#1 concern for consumers

Meat tenderness

Shear force testing

used to measure tenderness

An increase in ______ is strongly correlated with increased shear force values in raw meat

collagen

<3.9 = ______

tender

>4.6 = _____

tough

Vacuum packaging

PRO

extends shelf life

oxygen impermeable

Vacuum packaging

CONS

changes meat color

Overwrap

PRO

bright red color

product visibility

Overwrap

CONS

short shelf life (5–7 days)

increased bacterial growth

MAP

PROs

prolong shelf life

maintains strong color

MAP

CONS

induces lipid oxidation

(high O₂ systems)

Deoxymyoglobin

purple (no O₂)

Oxymyoglobin

bright red (O₂)

Metmyoglobin

brown (oxidized)

Low O₂ →

deoxymyoglobin

Oxygen exposure →

oxymyoglobin

Oxidation

metmyoglobin

Papain

papaya → MUSCLE

Bromelin

pinapple → collagen

Ficin

fig → muscle and collagen

pros of plant enzymes

degrade muscles and connective tissues

cons of plant enzymes

too soft or mushy

off flavors

why brahman cattle tend to be more tough 

Higher concentrations of calpastatin

prevents calpains from working → less tender

Locomotion muscles

= more collagen = tougher

Support muscles

= less collagen = more tender

Purpose of resting meat

Helps retain moisture and improve eating quality after cooking

Steps of lipid oxidation

Initiation →

Propagation →

Termination

Initiation

Abstraction of a hydrogen from a fatty acid (by a free radical), forming a fatty acid radical

Propagation

Fatty acid radicals continue to make more fatty acid radicals as they “bump” into each other and oxidizing each other

Termination

There is nothing left to oxidize, so lipid oxidation slows and eventually haults

Quantitative

Looking at NUMBERSi

Instrumental color, trained panels

Qualitative

consumer panels

L values

measure lightness

black and white

a values

measures redness

green to red

b value

measure yellowness

blue to yellow

myoglobin has a ______

free binding site

VEAL (myoglobin content)

2 mg/g

Calf

4 mg/g

young beef

8 mg/g

old beef

18 mg/g

tenderness depends on

• Actomyosin Effect

• Background Effect

• “Lubrication” Effect

locomotion muscles

chuck and round

support muscles

rib and loin

_____ animals have a greater amount mature collagen crosslinks 

Older

When ______ denatures it shrinks the sarcomere in diameter. 

myosin

1

Deoxymyoglobin (Fe2+)

2

carboxymyoglobin (Fe2+)

3

metmyoglobin (-Fe3+)

4

Oxymyoglobin (Fe2+)