ansc 351 exam 2

what does immobilization do

disrupts nervous system

what are approved immobilization methods

mechanical, electrical, chemical

what is exsanguination

massive bleeding

first step of exsanguination

blood pressure drops

second step of exsanguination

loss of circulatory system

third step of exsanguination

shift from aerobic to anaerobic

fourth step of exsanguination

pH drops

fifth step of exsanguination

lose temp control, increased heat production

sixth step of exsanguination

rigor mortis

stages of rigor

delay, onset, completion, resolution

what happens during delay

muscle is at original length and flexible

what happens in onset

losing flexibility, decreasing sarcomere length increases tension

what happens in completion

max tension, muscle inextensible, actomyosin crossbridges fully formed

what happens in resolution

protein breakdown, slight tension decrease

what happens in thaw rigor

muscle is frozen before rigor, when thawed there is a massive Ca dump causing a contraction, shortening sarcomeres (tough meat)

what happens in cold shortening

meat is at 15-16 celsius, same as thaw rigor but less severe

what is pse

pale, soft, exudative; due to acute stress

what meat can have pse

pork and turkey

pse metabolism before slaughter

increased heart rate and temp

atp depleted

switch to anaerobic

pse metabolism after slaugther

increase muscle temp

increase lactic acid

decrease pH

accelerated muscle to meat

pse results

denatured proteins

decreased water binding (purge)

myoglobin washed away (pale)

lose structural integrity (soft)

pse quality problems

looks bad

purge in package

very dry

doesn’t hold ingredients

what is dark cutters

due to chronic stress

what happens in dark cutters

slow pH drop

glycogen depleted

no fuel to convert atp through glycolysis

decrease lactic acid

increase water binding

dark cutters results

increase water binding makes color darker

less purge (dry appearance)

less denaturation (firm)

dark cutters quality problems

dark red/purple

very juicy

off flavor

holds water well (spoils faster because of higher water activity)

what causes bruising and broken bones

over/under filling transportation

poor handling

poor plant design

result of bruising or broken bones

product loss

how can stress and injury be reduced

genetic selection, facilities, handling management

what genes can be selected against for stress

halothane gene, rendement napole

what does halothane gene do

mutated Ca channel

more Ca leakage causing twitching

faster pH drop and increase temp

pse

what does rendement napole do

mutated AMP kinase causes more glycogen

increase lactic acid

decrease pH

what does rendement napole cause

acid pork

what are some common facility problems

steep ramps

slippery floors

air blowing in face

light shining in eyes

noises

dark doorways

what are some common handling/management problems

ill trained employees

people moving overhead

electric prodding

reproductive cycles

what proteins impact meat color

hemoglobin and myoglobin

what is the function of myoglobin

oxygen transport and storage

what is myoglobin made of

globin and heme ring

what does visual color depend on

oxidation state of iron (ferrous, ferric)

6th ligand binding site

what are the states of myoglobin

DeOxyMb, OxyMb, MetMb

what is DeOxyMb

most stable

nothing bound to ligand

ferrous

purple color

what is OxyMb

most desirable

O2 bound to ligand

ferrous

red color

what is MetMb

least desirable

H2O bound to ligand

ferric

brown color

how is myoglobin oxidized

oxygen

heat

light

oxidants (metal ions)

what impacts color

muscle composition

ingredients (oxidants, antioxidants)

packaging/handling

what are the types of packaging

aerobic

anaerobic

modified atmosphere

freezer paper

what is aerobic packaging

increased potential for bacteria, oxidation, freezer burn

product appears OxyMb

what is an example of aerobic packaging

PVC overwrap

what is anaerobic packaging

decreased potential for bacteria, oxidation, freezer burn

product is DeOxyMb

what is an example of anaerobic packaging

vacuum packaging

what is modified atmosphere packaging

increased quality, decreased microbe growth

gas mix (80% O2, 15% CO2, 5% N)

issues with modified atmosphere packaging

prior use of carbon monoxide

what is freezer paper

wrapped well -- anaerobic packaging

wrapped poorly -- freezer burn

palatability definition

desirable flavor and texture properties

what impacts palatability

tenderness, juiciness, flavor (appearance)

what impacts tenderness

connective tissue

sarcomere length

proteolytic enzymes

what is connective tissue

collagen and elastin (background toughness)

what is connective tissue impacted by

age, muscle location, sex

what impacts sarcomere length

actin myosin crosslinking → tightly packed → decreased water binding → increase protein density

how does sarcomere length impact tenderness

increase length increases tenderness

what do proteolytic enzymes do

degrade proteins post mortem

what is an example of proteolytic enzymes

calpains

what are the types of calpains

2 calcium dependent (m-calpain, u-calpain)

1 inhibitor (calpastatin)

what other things can impact tenderness

marbling

how does marbling impact tenderness

acts as lubricant for chewing, more related to juiciness and flavor

how can tenderness be improved pre rigor

carcass stretch and electrical stimulation

what does carcass stretching do

lengthen sarcomeres

what does electrical stimulation do

increase onset of rigor by accelerating glycolysis

accelerate enzymes with calcium release, disrupts fibers

what animals is electrical stimulation used on

cattle

how can tenderness be improved post rigor

aging, mechanical tenderization, freezing

what does aging do

allow enzymes to degrade

what is an example of aging

dry aging - intensified flavor, increases juiciness, more expensive

what does mechanical tenderization do

disrupts fibers

what does freezing do

ice crystals cut/break proteins, reduce juiciness

what is juiciness impacted by

intramuscular fat and water

how does intramuscular fat impact juiciness

melts during cooking

barrier to moisture loss

how does water impact juiciness

water holding capacity

how much muscles can retain water

what are the types of water

free, immobilized, bound

what water becomes purge

free water

what is the isoelectric point

when positive and negative charges on proteins are equal

the net charge is 0

how does isoelectric point impact water holding capacity

as the net charge approaches 0, proteins react/bind with each other and not water

how can juiciness be improved pre rigor

fat (marbling) and water

how to improve fat for juiciness

genetic selection and nutrition

how to improve water/reduce PSE likelihood for juiciness

reduce stress

genetic selection

proper temp control

how can juiciness be improved post rigor

fat (ground product) and water

how does water work to improve juiciness

brine enhancement

what is flavor

gustatory and olfactory

what is the primary source of flavor

fat

what other factors impact flavor

gender

muscle location

lipid oxidation

post mortem aging

processing ingredients

how can flavor be improved pre rigor

fat (marbling) and nutrition (flavor compounds of diet)

how can flavor be improved post rigor

aging

adding flavors

tenderize

what fruits are used to tenderize

pineapple (bromelain)

papaya (papain)

figs (fecin)

how is palatability measured

warner bratzler shear force

cook loss

gas chromatography

sensory analysis

what tests are done in sensory anaylsis

discriminative, affective, descriptive

what types is discriminative

difference

what question is discriminative answering

can you tell the difference

example of discriminative

triangle test

what type is affective

acceptance preference

what question is affective answering

significant difference/preference

example of affective

hendonic scales (whole number scales)