Meats Exam 2 (Lectures 9-11)

How to make meat more tender:

• Cause the sarcomeres to be longer.

• Disrupt the integrity of the myofibrils.

• Disrupt the integrity of the connective tissue.

Cold shortening

Process whereby sarcomeres shorten due to cold-induced nervous response. Results in tougher meat.

To prevent cold shortening:

Speed-up drop in pH in muscle (anaerobic glycolysis: glycogen → lactic acid; muscle pH 7.0 → 5.6).

and/or

Slowdown drop in muscle temperature.

Prevent cold shortening using subcutaneous fat thickness:

0.10 inch in lamb. 0.25 inch in beef. Slows down drop in muscle temperature.

Why doesn’t pork cold shorten?

Pork doesn’t cold shorten because of white muscle fibers.

Prevent cold shortening using high temperature, pre rigor chilling:

16 degrees Celsius for 16 hours immediately after slaughter.

Prevent cold shortening using electrical stimulation:

550 volts, 2-6 amps, 15 times in 1 minute. Speeds up drop in pH + quicker onset of rigor mortis.

How to stretch sarcomeres using TAMU tenderstretch?

suspension by obturator foramen. hindleg acts as a cantilever.

What are Stouffers stretching devices?

Used to stretch sarcomeres. TAMU tenderstretch plus clamps and stretching rods.

How to stretch sarcomeres using TenderCut?

Bone and connective tissue cut around muscle to allow stretching.

You can disrupt the integrity of the myofibrils by increasing the activity of what endogenous enzymes?

Calpains
Calpastatin

What does calpains do?

stored in the cytosol near Z-lines and require calcium to be activated

What does calpastatin do?

regulates calpains; the higher the calpastatin levels and activity, the less

breakdown of myofibrils.

How can you use cooler aging to disrupt the myofibrils?

storage for 1 to 6 weeks at 0-3°C.

how can you use High temperature, post-rigor chilling to disrupt the myofibrils?

Storage at 20°C for 24 hours. Same effect as 2°C for 14 days.

How can you use High temperature, pre-rigor chilling to disrupt myofibrils?

16°C for 16 hours.

How does electrical stimulation disrupt myofibrils?

rapid pH decline ruptures lysosome and releases cathepsins.

how does Calcium chloride infusion/injection disrupt myofibrils?

pre-rigor infusion or post-rigor injection of a solution

of calcium chloride into muscle. Causes increased activity of calpains.

The addition of what exogenous enzymes can disrupt myofibrils?

Tropical plant enzymes – Heat activated: Swift's Pro-Ten® (inject into live animal) or

Adolph's Meat Tenderizer® (sprinkle on meat).

Papain is?

Papaya

Bromelin is?

Pineapple

Ficin is?

Fig

Actinidin is?

Kiwi fruit

how can electrical stim cause severance of myofibrils?

violent contractions cause myofibril tearing

causing severance of a myofibril, what is a blade/needle tenderizer?

machines with multiple blades and/or needles that penetrate

meat as it passes through on a conveyor.

what was the first machine?

Jaccard (most people call the process “Jaccarding”).

causing severance of a myofibril, what is a mechanical severance?

chopping, grinding, dicing, cubing, scoring

causing severance of a myofibril, what is Hydrodyne?

placing meat in a sealed water-filled chamber and setting off an explosion.

Destroys most of the Z-lines to greatly improve tenderness.

Disrupting connective tissue what exogenous enzymes can we use?

Marination with salt and vinegar
Tropical plant enzymes
Rhozyme

What is marination with salt and vinegar?

water solution with 2% NaCl plus acetic acid.

What is rhozyme?

Fungal enzyme, Aspergiluus oryzae

What is another exogenous enzyme used to disrupt connective tissue?

tropical plant enzymes

What are 2 ways to cause severance of stromal proteins?

Mechanical severance
Blade/needle tenderization

How to use conversion of collage → gelatin to disrupt connective tissue?

Moist heat cookery- cook for a long time with steam generation: braise, stew, simmer

What does hue mean?

words we normally think of as describing color: red, purple, blue, etc.

What does chroma mean?

strength or dominance of the hue

What does value mean?

overall intensity to how light or dark a color is.

What does L* mean?

Black to white

What does A* mean?

red to green

What does B* mean?

yellow to blue

Structure of myoglobin

What is the difference between hemoglobin and myoglobin?

Hemoglobin – transports O2 from lungs to cells
Myoglobin – stores O2 in cells

How is meat color affected by age within species?

myoglobin loses its affinity to bind oxygen as age increases

What is the myoglobin concentration for a veal, calf, young beef, old beef?

Veal 2 mg/g

Calf 4 mg/g

Young beef 8 mg/g

Old beef 18 mg/g

how does species difference affect myoglobin concentration?

How does the type of muscle affect the myoglobin concentration?

the more a muscle is used, the more myoglobin it needs

Does a locomotive or support muscle have more myoglobin concentration?

Locomotive like M. extensor carpi radialis (12 mg) has more than Support like M. longissimus thoracis et lumborum (6 mg)

Meat color is affected by…

quantity of myoglobin

Fe++ (Ferrous) + H2O makes what color and name?

Purple, Deoxymyoglobin

Fe++ (Ferrous) + O2 makes what color and name?

Red, Oxymyoglobin

Fe++ (Ferrous) + NO makes what color and name?

Light pink, nitric oxide myoglobin

Fe++ (ferrous) + CO makes what color and name?

Red, carboxymyoglobin

Fe++ (ferrous) makes what kind of bonds with its compounds?

Covalent

Fe+++ (ferric) and CN makes what color and name?

Red, cyanmetmyoglobin

Fe+++ (ferric) and OH make what color and name?

Brown, metmyoglobin

Fe+++ (ferric) and SH make what color and name?

Green, sulfmyoglobin

Fe+++ (ferric) and H2O2 make what color and name?

Green, choleglobin

Fe+++ (ferric) makes what kinds of bonds with its compounds?

Ionic

From deoxymyoglobin to oxymyoglobin, what happens?

Oxygenation

From oxymyoglobin to metmyoglobin, what happens?

oxidation

From metmyoglobin to deoxymyoglobin, what happens?

reduction

from deoxymyoglobin to metmyoglobin, what happens?

oxidation

from metmyoglobin to oxymyoglobin, what happens?

reduction

What is the Metmyoglobin Reducing Activity (MRA)?

The system within the muscle that converts metmyoglobin to oxymyoglobin and deoxymyglobin through a series of reactions until reductants are depleted.

what muscle has high MRA?

M. longissimus lumborum

what muscle has the least MRA?

M. psoas major

what is the oxygen consumption rate?

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 has high OCR?

M. psoas major

what muscle has least OCR?

M. gluteus medius

What muscles have high color stability?

M. longissimus lumborum

M. longissimus thoracis

M. semitendinosus

M. tensor fasciae latae

What muscles have moderate color stability?

M. semimembranosus

M. rectus femoris

M. vastus lateralis

What muscles have intermediate color stability?

M. trapezius

M. gluteus medius

M. latissimus dorsi

What muscles have low color stability?

M. triceps brachii – long head

M. gluteobiceps (M. biceps femoris)

M. pectoralis profundus

M. adductor

M. triceps brachii – lateral head

M. serratus ventralis

What muscles have very low color stability?

M. supraspinatus

M. infraspinatus

M. psoas major

what are 2 meat color problems with cooked ground beef?

premature browning and persistent pinkness

premature browning is caused by?

highly oxidized meat or meat that is exposed to high-oxygen atmospheres

meat turns brown around what temperature?

130 degrees Fahrenheit

persistent pinkness is caused by

high pH. Product will stay pink (uncooked color) even with degrees of doneness that should ensure appropriate cooked endpoints are followed.

vitamin E can be fed to livestock to?

increase the alpha-tocopherol concentration in muscle.

what is alpha tocopherol?

an antioxidant and retards the conversion of deoxymyoglobin (purple) or

oxymyoglobin (red) to metmyoglobin (brown)

Oxymyoglobin + oxidation + bacteria =

metmyoglobin (-OH)

Metmyoglobin + bacteria =

Choleglobin (-H2O2)

Metmyoglobin + bacteria =

Sulfmyoglobin (-SH)

To cure,
Deoxymyoglobin, oxymyoglobin, metmyoglobin + NO =

Nitric oxide myoglobin

To cure, Nitric oxide myoglobin + heat =

nitrosyl hemochromogen

Vacuum packages (polyvinylidene chloride–polyvinyl chloride);

Barrier to O2

Retail film (polyvinyl chloride);

Permeable to O2

what is IBP Cattle-Pak?

Seven-box style of boxed beef where there were two boxes of rounds, two

boxes of loins, two boxes of chucks, and one box that contained both ribs that were sold as a unit.

Eventually boxed beef shifted from primals (___________) to subprimals (__________).

Primals: e.g., round, loin, rib, and chuck

Subprimals: e.g.,inside round, eye of round, bottom round, top sirloin butt, strip loin, tenderloin, ribeye, chuck roll, clod

Who are the pioneers in boxed beef?

Tyson-IBP, JBS- Swift, Cargill

By their dominance in boxed beef, this has allowed these three companies to control around __% of the fed beef slaughter and __% of the boxed beef production in the United States.

75, 85

Today, virtually of all beef produced is _____.

boxed

Who was the pioneer in packaging?

Cryovac®, a division of Sealed Air®, was instrumental in developing both the packaging materials and equipment for boxed beef to happen. Cryovac®-brand food packaging is the dominate supplier in the food industry today.

What are the wholesale packaging systems?

Vacuum packaging
Heat shrinking
Leading bags for beef, pork, and lamb wholesale packaging
Vacuum packaging equipment

Vacuum packaging is?

For fresh beef, pork, and lamb, most are vacuum packaged using heat-shrink packages.

Heat shrink packages have the ability to?

shrink around the product when exposed to heat, either by air (400°F) or by water (200°F).

Non heat shrink packages do not have the ability to?

shrink once they have been manufactured. These are most commonly used for processed products such as jerky, cheese, etc.

What is the importance of heat shrinking?

• Help bag conform to the surface of meat to reduce flex cracks

• Helps eliminate pockets where purge can accumulate

• Thickens bag to add to puncture resistance

• Improves oxygen barrier properties

What are the Leading bags for beef, pork, and lamb wholesale packaging?

Cryovac® brand barrier bags and Cryovac® brand abuse resistance bags

What are Cryovac® brand barrier bags?

Uses layers such as Saran® or other oxygen-barrier materials to provide low oxygen transmission rate (OTR) and low moisture vapor transmission rate (MVTR) allowing excellent shelf life.