ANSC 201 Exam 1

primary follicles

bigger, first to develop, arranged in groups of 3

* fibers fully emerged at birth, accessory structures present

secondary follicles

smaller, associated with primary, fibers emerge between 1-3 weeks

* incomplete structure

factors affecting follicle developement

adverse prenatal environment

early postnatal environment

what type of follicles do consumers prefer?

secondary, more refined

what is the structure of wool?

* cuticle
* cortex
* medulla
* kemp

what is wool cuticle?

in all wool fibers, scaly outer layer

what is wool coretex

needle-like cells


1. ortho: soft elastic
2. para: hard, less elastic

determines crimp of fiber

what is wool medulla

hollow air space, absent in fine wool

what is wool kemp

large fibers without solid core

what is fleece vs clip

fleece: wool from single sheep

clip: wool from flock

what is the primary constituent of fiber?

* keratin (protein)
* long flexible polypeptides
* chem: sulfur containing aa
* arrangement: sulfide bonds hold chains in helical structure

what factors affect amount of wool produced?

nutrition: sheep need adequate protein and energy for wool

breeding

what are the selection criteria for fibers

* fleece weight
* fineness of hair
* length of fibers

what are the types of wool impurities

1. natural: produced by sheep, grease
2. acquired: dirt, manure
3. applied: sprays

what characteristics determine the value of wool?

1. yield
2. grade

what is wool yield?

* wool weight remaining after cleaning

what is wool shrinkage?

wool weight lost due to impurities

what criteria are used to determine wool grade?

* fiber diameter


* American blood
* spinning count
* micron diameter
* length
* color

what does it mean to prepare for spinning and weaving? (steps of wool growth)

1. growing
2. shearing
3. grading
4. sorting
5. blending
6. scouring
7. carding

what are the pros and cons of wool

pros: warm, non-flammable, absorb moisture and trap air

cons: shrinks, itch

what are examples of other types of fibers?

angora, mohair

cashmere

alpaca/llama

what is lanolin?

refine wool grease

what is red meat?

beef, pork, veal, lamb/mutton, horse

what is poultry?

chicken, turkey, duck, goose

what is the more consumed meat in the world? US?

pork

poultry

what are the primary muscle types?

smooth

involuntary striated

voluntary striated

what are smooth muscles?

walls of digestive tract, capillaries

what are involuntary striated muscles?

cardiac muscles

what are voluntary striated muscles?

skeletal, have alternating dark and white bands

* make up most of meat

what are myofibers

muscle fibers: structure unit of muscle

what is the structure of muscle?

1. sarcolemma: excitable outer cell membrane
2. nuclei: voluntary striated, multiple; smooth and involuntary striated, single nuclei
3. myofibrils: longer fibers of contractive filaments in myofibers
4. sarcoplasm: liquid portion of cell

what is the connective tissue network?

1. endomysium
2. perimysium
3. epimysium

what is the endomysium?

thin layer surrounding each cell

what is the perimysium

wrap around several muscle cells and form a bundle (primary and secondary)

what is the epimysium?

surrounds entire muscle

what is the sarcomere?

smallest functional contractile unit

* contains several hundred filaments between z lines

what are the muscle fiber

myofibrils

contraction and relaxation

what is myofibrils

permit each cell to work


1. actin: think filament, light band
2. thick filament, fark band

sliding filament theory

regulated by \[Ca++\]

* calcium help in sarcoplasmic reticulum surround myofibrils

what is the role of ATP in contraction and relaxation?

relaxation: keep actin and myosin separated

contraction: produce energy

what is anaerobic?

* without Oxygen
* more likely to take place in dead animals

what is aerobic?

* with oxygen
* produces more energy

what are the three steps of the rigor curve

1. rigor onset
2. rigor completion
3. resolution of rigor

what is rigor onset?

muscle relaxed and more tender

pH dropping due to lactic acid build up

what is rigor completion?

max contraction and max toughness

what is the resolution of rigor

muscle becomes more tender due to enzyme breaking down proteins

* autolysis: self break down
* enzyme: cathepsins and calpains
* pH: 5.6 b/c h2o binding capacity drops w/ pH

what is the pH at the resolution of rigor?

5\.6

when pH becomes 5.6 enzymes begin breaking down muscle structure

define rigor mortis

stiffening of carcass by intense shortening of muscle fibers

what are the methods of meat aging

1. 7-14 days at 35\*
2. 2-3 days at 60\*-80\* (uv light)
3. additional proteolytic enzyme (papain)
4. wet aging: meat retained in its own fluid

what is the chemical composition of meat?

water: 75%

protein: 19%

lipids: 4%

carbs: 1%'

minerals: 1%

\
solids: \~25%

snf: \~21%

what are lipids in monogastics?

reflect their diet

pork: 54% unsat.

what are lipds in ruminants?

more uniform

* beef: 46% unsat.

what are lipids in poultry?

2/3 unsaturated

1/3 saturated

what is the most common fatty acid in meats?

oleic

how does meat rank in terms of nutritional value?

3rd

(egg → milk → meat)

how does nutritional value differ from species?

value of proteins in different species is about the same regardless of the cut

what are specific proteins in meat?

1. actomyosin: major protein


1. myoglobin: transports O2 and CO2 withing muscle tissue

what are the major carbs in meat?

glycogen (before rigor) and lactic acid (after rigor)

* others: glucose derivatives

what are major vitamins in meat?

* B12, niacin, riboflavin, B6
* beef high in B12
* pork high in: thiamine

major minerals in meat?

* Fe, Zn, K, S, Na, Cl, Mg, Ca, P

how do consumers determine meat quality

* color and texture
* aroma and flavor
* juiciness
* tenderness

what determines color and texture of meat?

myoglobin

* used muscle: more myoglobin, darker
* unused muscle: less myoglobin, lighter

\
color also impacted by pH of muscle

what is the desirable color of meats?

* beef: bring cherry red
* pork: grayish pink
* mutton: light pink
* veal: pinkish brown
* poultry: golden yellow, varies by diet

what has more influence on flavor?

fat soluble compounds

volatile compounds are liberated by what

heating

define juiciness

wetness produced by release of meat fluids

* second to tenderness in importance as palatability

what influences juiciness

cooking procedure and fat

more fat marbling, more juicy

what is tenderness?

measurement of how easily meat can be cut/chewed

* resistance to shear force

what factors influence tenderness?

a) connective tissue: more connective tissues = less tender

b) cooking method: myofibrils become tough with heat

c) time and temperature storage

d) muscle fiber coarseness: small fibers more tender

what does an other animal mean with meat

older animal is less tender, but more flavorful

what preslaughter practices impact quality of meat?

1. hereditary (tenderness = hereditary)
2. physiological


1. age and hormone (bigger deal if older)
3. feeding and management
4. stress

what post slaughter practices impact quality of meat

1. chilling


1. aging
2. freezing
3. electrical stimulation

what is electric stimulation of meat?

makes rigor more uniform by contracting all muscles at the sale times

* improves color and tenderness

what meat is aged?

ruminant meat: increases tenderness

* monogastric meat is higher in unsaturated fats aging may cause oxidized flavor

how is dressing weight calculated?

(carcass weight/live weight)x100

what is the common dressing percentage of sheep, cattle, and swine?

what is meat inspection?

* paid for by taxes
* federal law mandatory

what is the wholesome meat act

every slaughtered animal must be inspected

what is the purpose of meat inspection?

ensure meat is wholesome and suitable for consumption

what does the meat quality inspection entail?

* free of disease
* clean and sanitary facility
* proper labeling and packaging

what is meat grading

option, paid by packer

* based on aspects of meat desired by customer

what animals have higher percent dressing?

monogastric

what are the grades for beef?

prime, choice, select, standard

what is beef yield grade

* 1,2,3,4,5
* measures quantity


* based on fat area, ribeye muscle, and weight

what is the pork yield/grade system

based on backfat, muscles, lean cuts

* 1,2,3,4

what is the most common pathogen

salmonella

recommened cooking temperature

160\* for ground meats

what are the body enviornment

external: gaseous

internal: aqueous

fluid filled spaces: what is intracellular

fluid between cells, 45% bw

fluid filled spaces: what is interstitial

fluid between cells, 17% bw

fluid filled spaces: what is circulatory system

blood plasma, 6% bw

define homeostasis

body mechanisms that work to maintain equilirbium

what systems are involved in regulating equilibrium?

1. circulatory system: permits exchange of nutrients/gas/hormone
2. respiratory, urinary, digestive, muscular
3. nervous

how does the nervous system help maintain eq?

makes adjustments

detects environmental changes

somatic vs autonomic

somatic: control skeletal muscles

autonomic: control involuntary muscles

what are the branches of the autonomic system?

sympathetic: emergency

parasympathetic: at rest

when a change in environment requires a rapid body response what brings that about?

nervous system

what does the endocrine system do?

secret organic substances to be exchanged by circulatory system

what is endocrine vs exocrine

endocrine: secreting

exocrine: exiting

when a change in environment requires a specific response for altering cell environment what is responsible for this?

endocrine system, takes longer time to respond