MEAT PT 1 Flashcards
define meat
skeletal muscles of mammals; may also include organs and glands and technically excludes flesh of non-mammals (poultry and flesh)
whats the problem with beef cattle lymph nodes
undesirable parts of cattle get grinded up and spreads; product has more H2O and surface area; quality lower
whats meat composed of
water, muscle tissue, connective tissue, adipose (fatty) tissue + sometimes bone
do proportions of meat composition vary according to animals source and cut of meat
yes
what does muscle tissue structure
bundle of muscle fibers, myofibril (contractile unit), muscle (muscle cell); wrapped into membrane and filled with liquid
what is each muscle fiber (cell) surrounded by
outer membrane called sarcolemma
what is each muscle fiber cell filled with
cellular fluid called sarcoplasm that contains thousands of myofibrils
what do smaller + more numerous muscle fibrils result in
smaller muscle bundles, which creates delicate/velvety meat
what are the contractile units of muscle
myofibrils
what are fibrils separated into units called
sarcomeres
what are sarcomeres bordered by
Z-lines
what proteins do sarcomeres contain
actin and myosin
describe actin + what minor proteins it contains
thin filament; contains tropomyosin (stabilizes actin structure) + troponin (contains Ca-binding protein)
describe myosin
thick filament
what initiates contraction
nerve impulse
what happens when Calcium ions are released into sarcoplasm
bind to troponin, moves tropomyosin so myosin can bind; actin and myosin form actomyosin cross-links and myosin pulls actin towards center and the sacromere shortens
describe relaxation of muscle contraction in three points
nerve impulse stops when Ca is pumped out of sarcoplasm; actin myosin cross-links break; sarcomeres return to original length
whats rigor mortis
“stiffness of death,” within 24 hours of slaughtering, muscles enter temporary stiff state (reverses after 1 - 3 days)
what happens to blood flow during death
stops blood flow, no O sent to cells, which enter anaerobic glycolysis at last resort to make ATP; glucose turns to lactic acid and pH is decreased
what happens when glycogen stores are used up
no more ATP, so actin and myosin cannot dissociate which causes maximum stiffing (aka stuck in contracted state)
what happens during gang (holding meat after slaughter)
endogenous enzymes degrade sacromere framework, which makes tenderness increase
are pH and moisture retention correlated? how does this impact meats
yes; pH decreases when cell enter anaerobic glycosides so moisture retention decreases during rigor mortis
are glycogen levels in animals before they’re killed important
yes
what happens to glcoygen levels when animals are kinda at rest
go up before kill which contributes to quality
what does the decrease in pH do
decrease in ph from lactic acid accumulation influences meat quality
what leads to water loss
decreased microbial growth
whats water holding capacity (whc)
the ability of a matrix to physically entrap water; decreases at pH approached during rigor mortis
describe pH and meat quality
if pH too high. microbial growth will occur and if pH too low, there will be too much water loss; its important to maintain optimum pH to retain quality; if pH is not in right range, meat won’t hold water
describe the composition of meats
connective tissue, with collagen, elastin, reticulin
whats connective tissue
mixture of proteins and polysaccharides that act as glue and hold muscle cells together
whats collagen
most abundant CT protein; tough and fibrous but softens upon heating; has unique triple helix structure held together by H bonds and covalent cross links
whats elastin
protein in CT; has elastic properties
whats reticulin
protein in CT; forms interlace around muscle cells for support
how do the proteins and polysaccharides in CT form a glue
by forming covalent bonds
what happens to meat composition as animals age
2 things: collagen content increases + more covalent cross-links are formed within collagen helixes (which leads to toughening)
what happens to tenderness as animal age decreases
tenderness decreases
describe tougher cuts of meat from older animals
less expensive and require slow, moist-heating at low temps to hydrolyze collagen to gelatin
whats adipose tissue
fat serves as insulation and padding for sensitive organs; cover fat + marbeling
whats cover fat
appears on outside of meat
whats marbling
intramuscular fat seen as white streaks; well marbled beef more expensive + higher quality; contribute to flavor and jucness
what does marbling depend on
animals, diet, lifestyle, etc
what does fat content depend on
animal genetics, age, diet, exercise, cut of meat
whats Kobe beef
special grade of beef from wagyu cattle
what are bones used for
used to identify meat cuts
what is bone marrow
soft fatty material in the center of bones; valued food in many cultures and can provide flavor to soup
describe antibiotics in composition of meats
given to ensure health and promote growth; may contribute to development of antibiotic-resusttant bacteria
describe hormones
given to encourage rapid weight gain; reduces production cost; concerns over safety of residues in human health and environment
whats organic beef based without
antibiotics and hormones
whats the color of meat primarily from
very important; from pigment-contains protein myoglobin
whats the pigment portion of myoglobin
heme
what happens when meat is exposed to oxygen
changes color
whats color is internal meat and what happens when exposed to oxygen
internal meat: purple - red myoglobin
when cut from carcass + exposed to O - bright red oxymyoglobin
what happens when to meat color during storage time
may be further oxidized and become brownish-red metmyoglobin
whats the number one fact influencing consumers when purchasing meat
color
what does beef originate from PRIMARILY
cattle of various sex/age and breeds; primarily heifers (F that haven’t had calves) and steers (young, castrated males)
whats veal
m or f young calves; 3 weeks - 3 months
what are yearling beef
older calves
what are veal fed
milk-based diet + restricted in movement
describe veal in three ways
- unique flavor (influenced by presence lactic acid)
- fine/tender muscle fibers
- free-range veal is slightly less tender
