Meat Tenderness
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Transcript of Meat Tenderness
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Improving Meat Tenderness
Dr. John Marchello and Dr. Ron Allen
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Outline (for the boring part of the talk)
Why is meat tender or less tender (tough)
Muscle structure and contraction
Rigor mortis and meat tenderness
Post-mortem aging of meat
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Fundamental Aspects of Meat
Tenderness
Background Aspects of Tenderness
Primarily Connective Tissue
Muscle use
Age
Contractile Machinery
Degree of contraction
Integrity of the contractile machinery
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Muscle Structure
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Muscle Structure
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Muscle Contraction
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Rigor Mortis
Muscle continues to contract and relaxafter death
Without oxygen, lactic acid builds up
Energy production stops
Muscle filaments permanently locktogether
Muscle becomes stiff If filaments lock in a relaxed state, muscle
is tender
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Cold Shortening
Cold temperature causes contraction
Filaments lock together in a contracted
state
Rate of chilling and Rate of rigor mortis
affect cold shortening
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Postmortem Aging
Calcium activated enzymes
(Calpains) break filament structure
Breakdown of contractile machinery
integrity increases tenderness
Calpastatin, an inhibitor of calpains
prevents breakdown and decreases
tenderness
Nutrition, management and geneticscan affect levels of Calpains and
Calpastatins - therefore, tenderness
can be altered.
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Outline
Why is meat tender or less tender (tough)
Rigor mortis and meat tendernessstateof contraction determines tenderness
Post-mortem aging of meatdegradation
of contractile machinery by Calpainenzymes results in increased tendernessduring aging
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How can we control these factors?
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METHODS USED TO
TENDERIZE MEAT
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PALATABILITY
Of the six meat palatability factors(tenderness, juiciness, flavor, aroma, color,texture), tenderness is generally consideredthe most important palatability factor by theconsumer.
In recent years, the meat industry has madegreat progress in improving tenderness boththrough genetics improvement and meatscience technology.
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DIFFERENT MUSCLES
Different muscles in the meat animal have differentfunctions.
Some muscles are defined as muscles oflocomotion. These muscles are used to move theanimal and as a result of this function, they are lesstender.
The other muscles in the meat animal are calledmuscles of attachment. They do very little work andas a result of less work they are more tender.
They are often called middle meats and they sell fora higher price because of their tenderness.
Muscles found in the loin and rib are examples ofmuscles of attachment.
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Muscles of attachment
Major muscles of locomotion
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After death, the muscle fibers contract as the lactic acidcontent increases in the muscle.
This is known as rigor mortis and this occurrence causesmuscle to become less tender especially in young cattle.
Rigor is complete after about 48 hours post-mortem. The lacticacid is produce after death from glucose which is stored inmuscle.
This is called post-mortem glycolysis and occurs withoutoxygen. Rigor causes the muscle to shorten which results inmuscle toughening.
Therefore, the muscle contractile unit called the scarcomeremust be broken down to improve tenderness which will allowthe heat of cooking to further improve tenderness.
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As a consumer, how do you measure
tenderness of a steak?
Some people determine tenderness by
how easily the teeth sink into the piece
of steak upon first bite.
Others determine tenderness based
upon the number of chews before the
piece is swallowed.
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SHEAR FORCE
From a research standpoint, a number ofprocedures are available to measuretenderness.
One of the best procedures is determining
the pounds of force required to shear a inch core of the steak.
The steak is cooked to 160O F and at least 8- inch cores are removed from the steak and
a Warner-Bratzler shear machine is used tomeasure the pounds of force required toshear the core.
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A METHOD OF TENDERNESS EVALUATION
Warner- Brazler Shear Force
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Cooking to measure tenderness by
shear force value
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Coring for shear force
measurements
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Shear values less than 7 VERY
TENDER
7 to 10 tenderness decreases as shear
value increases
10 and up -- tough
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SHEAR FORCE VALUES
WAGULI VS. BRAHMAN
Waguli
5
11
4
7
13
1
3
6
1
7
____________________________
5.8
Brahman
11
17
9
2
8
3
13
10
7
15
______________________
9.5
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TENDERIZATIONPROCEDUIRES
DRY AGING
WET AGING
ELECTRICAL STIMUALTION
MECHANICAL TENDERIZATION
GRINDINGCHEMICAL
DRY AGING
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DRY AGING
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VACUUM PACKAGING
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VACUUM PACKAGING
WET AGING
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PROTEOLYTIC ENZYMES
Cathepsins from lysosomes
Calpain two types u & m Macro Ca++ and Micro Ca++
Calpastatin depresses Calpain action
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SHEAR FORCE VALUES
WAGULI VS. BRAHMANWaguli
5
11
4
7
13
1
3
6
1
7
Av 5.8
Brahman
11
17
9
2
8
3
13
10
7
15
Av.9.5
Brahma carcasses possessed 3
times more Calpastatin than the
Waguli cattle carcasses
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ELECTRICAL
STIMULATION
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TEXAS TENDER STRETCH
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MECHANICAL
TENDERIZATIONBlade tenderizing
Stainless steel bladesPenetrating the muscle
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BLADE TENDERIZATION
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CHEMICAL TENDERIZERS
Papain extracted from papaya
Bromelain extracted from pineapple
Ficin extracted from figs
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CHEMICAL TENDERIZERS
Primal cuts such the rib or loin care
injected with the enzyme
The steaks are cut from the primal cutsand cooked.
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The heat of cooking will activate theseproteolytic compounds to helptenderize during the cooking process.
These enzymes are activated by heat atabout 100o F and deactivated at 140o F.
There are chemical tenderizers that can
be purchased for home use as well.
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OVER COOKING MAY CAUSE A
DECREASE IN TENDERNESS