Test 2

What is the most important cue for consumers at the point of purchase?

Color of meat

What are the cues consumers look at before purchasing meat

Color, cut, fat

What are the cues after purchase that determine consumers satisfaction and future purchasing decisions

Tenderness, juiciness, flavor

What quality would a tenderloin be

High-quality = very tender

What quality would a eye of round be?

Low-quality = very tough

What is the most variable eating quality attribute?

Tenderness

What is an instrumental measurement that uses a V-shaped blade to cut a core of meat called?

Warner-Bratzler Shear Force (WBSF)

what type of sensory analysis would determine how much you like the tenderness?

Consumer panel analysis

Why don’t we use consumer panels as much?

Consumers are not as repeatable

What sensory analysis determines the hardness, cohesiveness, and residue after chewing?

Trained panel analysis

What are the three factors that determine tenderness?

Connective tissue, sarcomere length, and postmortem proteolysis

What factors influence the tenderness prior to, during, and after harvest?

animals age, muscle location, rate of chilling, postmortem aging

What connects parts of the body together?

Connective tissue

T/F: Connective tissue has relatively few cells but is still considerable an extracellular substance

True

What is the composition of connective tissue

Collagen, and Elastin

T/F: Elastin is more abundant than collagen

False

What is the most abundant protein in an animals body?

Collagen (20-25%)

What is a molecular chain of glycine, proline, and other amino acids?

Procollagen

What is a triple helix of procollagen chains called?

Tropocollagen

What is tropocollagen aligned longitudinally end-to-end with 25% staggering called

Collagen fibril

What is a grouping of collagen fibrils called?

Collagen fiber

T/F: We can break elastin down when cooking, and collagen does not stretch?

False

Are frequently used muscles in limbs high or low in collagen?

High

Would the muscles around the spinal column be high or low in collagen?

Low

What makes collagen fibers so difficult that is high tensile strength and low solubility?

cross-linking

What is the primary factor that determines tenderness of older animals?

Extent of cross-linking with animal age

how can we raise collagen solubility, so long as marbling is also achieved?

Feeding high-concentrate diet to mature beef animals

What may disrupt the structure of the perimysium?

Adipocytes

Cuts high in connective tissue are suited for ___ __or__ _________ cookery

Moist heat, low-temperature long-time (LTLT)

what does collagen degrade to when it is cooked at 62-64 degrees C

gelatin

Are long sarcomeres generally more or less tender?

More tender

What is an alternative method of carcass suspension where the carcass is hung by the pelvis rather than achilles tendon

Tenderstretch

If I wanted to assess how much residue is left after chewing my product, what would \n be the best method to utilize?

trained sensory panel

What are the primary determinants of meat tenderness?

Sarcomere length, postmortem proteolysis, and connective tissue

When collagen degrades, what does it turn into?

Gelatin

What is storage of meat in controlled environmental conditions called?

Postmortem aging

What is the most common form of aging where the meat is aged in a vacuum bag?

Wet aging

What does wet aging do?

Minimized loss due to trimming, and improves tenderness and juiciness

What is the traditional form of aging called where the meat is aged without a protective barrier?

Dry aging

What does dry aging do?

Improves tenderness, juiciness, and flavor, and there is substantial loss due to trimming

During aging, does tenderness increase or decrease?

Increase

how long does it take for most of the tenderization to occur postmortem?

during the first 72 hours

T/F: During postmortem aging, tenderness increases through the weakening at the z line and myofibrillar fragmentation?

True

What are Calpains

A family of calcium-activated proteases (present in sarcoplasm of skeletal muscle)

What are the two primary isoforms of Calpains

Calpain-1, and Calpain-2

which cytoskeleton and regulatory proteins degrade during postmortem aging?

desmin, TnT

Which primary isoform of Calpains needs 10x as much calcium for it to work?

Calpain-2

When calpain autolyzed, it becomes active but is _____ stable

Less

What is necessary for calpain autolysis from the sarcoplasmic reticulum?

Ca2+

When does Calpain-2 autolysis occure?

When Ca2+ levels are high

What inhibited Calpains, and reduces rate of protein turnover. Also occupies the active site of calpain

Calpastatin

What is the term for when sheep have exaggerated hypertrophy in their hindlimbs? (trait only expressed in individuals who are heterozygous and inherited mutation from paternal)

Callipyge

What does overexpression of calpastatin lead to

less calpain activity and impaired tenderization

What can be done to enhance calpain activity and overwhelm calpastatin by release of Ca2+

Electrical stimulation

T/F: all meat tenderizes the exact same during postmortem aging

False

Which cut of meat has extremely long sarcomeres, hardly any postmortem proteolysis, and is extremely tender? (low collagen content)

Tenderloin

Which cut of meat is moderately tender, short sarcomeres, but extensive postmortem proteolysis? (low collagen content)

loin

Which cut of meat is tough, has moderate proteolysis, but extremely high collagen content?

Eye of round

What machine uses blades/needles to physicaaly disrupt muscle structure

Mechanical Tenderization

What does mechanical tenderization do to meat?

Improves tenderness at expense of juiciness, and risks introduction of pathogenic bacteria

what is extended aging duration

aging to 28 days or beyond to try and improve tenderness of some muscles but not others

What can exogenous calcium added to postmortem meat enhance?

calpain activity

What can exogenous enzymes from tropical fruits do to meat?

degrade myofibrillar and/or stromal proteins

what can tumbling immediately improve?

Tenderness of LL through fragmenting myofibrils

what can tumbling disrupt?

membrane structure, resulting in release of Ca2+

What is the primary reason *Bos Indicus* beef remains tough?

Insufficient proteolysis

What is the primary reason the *semitendinosus* (eye of round) cut of beef remains \n tough?

High connective tissue

What is the ability of meat to hold onto its water when external pressure is applied called?

Water-holding capacity

What does unnacceptable water holding capacity cost producers and retailers ?

Shrink

What is accumulated moisture that comes out of the meat product known as?

Purge/exudate

Poor WHC also typically results in poorer _______

Juiciness

If meat looks attractive in packaging, and has no evidence of moisture loss; which sets expectations for a juicy eating experience it has?

little to no display weight loss

If meat looks not attractive in packaging, and causes consumers to not purchase it based on expectations of a dry eating experience, it has?

Obvious display weight loss

when cut block of meat weighing 30-100 g and suspend in bag or airtight container for 1-2 days

Gravimetric (drip loss)

What does Gravimetric (drip loss) do?

determines driploss as percent weight change before and after hanging

Cut chop/section of meat and vacuum package (negative pressure of vacuum will drive moisture loss)

Purge loss

How long are you supposed to purge loss?

14-28 days

cut chop, vacuum package, and freeze at common temperature (generally -40\*)

freezing/thawing loss

cook chop at standard temperature to standard degree of doneness (generally 71\*C)

cooking loss

Where is most water located within myofibrils between thick and thin filaments

intramyofibrillar moisture

Where is the rest of the water located between myofibers and muscle bundles

Extramyofibrillar moisture

what is 1% of water in meat that is tightly associated with charges groups on proteins and does not leave?

bound water

What is 85% of water in meat that is associated with bound water?

immobilized/entrapped water

what constitutes the remaining water in meat that can be easily mobilized and readily leaves upon exposure to force?

free/bulk water

What are the 2 major factors that influence WHC

Net charge/pH effect, and steric/spatial effect

T/F: at a neutral pH (7.0), muscle proteins have an overall negative charge

True

as pH decreased during conversion of muscle to meat, _____ builds up and environment acidifies

H+

What does excess H+ ions interact with to neutralize their charge

Negatively charged amino acids

At neutral/ basic pH, muscle proteins have an overall _______

Negative charge

As pH decreases, the net charge begins to

equal 0

If pH is below the isoelectric point, proteins will have a net _______

positive charge

Where do we want to keep the pH at

as high as possible (pH of 5.6 - 5.9)

less glycogen in muscle→

less available to be broken down into H+ and lactate

minimizing acute pre-slaughter stress can accelerate

post mortem metabolism

salt has the unique property to ____ the isoelectric point of meat, while phosphates work to ____ the pH

Decrease, increase

Discoloration in meat costs the meat industry about $3 billion annually, because consumers interoperate deviations of color as

Spoilage

meat pigments include

myoglobin and hemoglobin

what transports oxygen in muscle

myoglobin

what transports oxygen in blood

hemoglobin

What water-soluble protein impacts meat pigments?

sarcoblasmic