Topic 8: Meat Flashcards
What makes meat a red color?
the red color is derived from myoglobin (recieves oxygen from blood and serves as oxygen storage in muscle)
color intensity increases with animal age, more exercised muslces are darker red because of more demand for oxygen
older meat cuts look browner
What affects the palatability of meat
tenderness, juiciness, flavor, color, texture,
Composition of meats
water, muscle, connective tissue, fatty tissue, bone, vitamin B (B1, B2, B12, folate), minerals (zinc, copper, phosphorus, etc.)
types of muscles?
cardiac, skeletal & smooth
what determines tenderness of meats?
less excercised, younger age, less connective tissues, more fatty tissues
what are more tender cuts of meat?
tenderloin, rib, short loin, sirloin (also priced higher)
less tender cuts of meat?
chuck, round
least tender cuts of meat?
brisket, flank , short plate, shank
would take longer to cook to make soft
How are cuts identified?
the bones attached to pieces of meat help to identify the cuts, it also helps confirm the quality of meat
what is marbling?
the distribution of fat in the meat
what does beef grading depend on in the US?
the USDA, uses a 1-5 rating system to describe the usable carcass meat, as well as a prime>choice>select rating ov marbling in the meat
how does grading beef work in Japan?
they use a letter + number grading system raning from A-C (The letters determine lean beef meat) where as the numbers determine marbling (5) or high in fat (1)
A itself has various levels
A1- A5
A1<A2<A3(3-4)<A4(5-7)<A5(8-12)
what is US prime steak comparable to in Japan?
A4 steak
How can the tenderness of meat be improved (harvesting)?
- Choice of animal, species, genetics (eg. Black angus cattle, dairy cattle)
- type of diet fed, grain fed cattle is more tender than hay
- post slaughter treatment (winthin 6-24 hours muscles enter state of rigor mortis, lasts for 1-2 days, meet should be cookd prior to rigor mortis)
What is rigor mortis?
describes when the the meat becomes hard and inextensible as the muscle tissue contracts. ATP is typically admisnistered to induce the the production of lactic acid, decreasing the pH, this prevents the irreversible cross linkage that contracts the muscles in the meat
What pH of meat is good quality?
pH of 5.5
what are the steps post-slaughter?
- stretch muscles by tenderstretch (hanging carcass to maximize tension until onset of rigor mortis)
- optimum temp 15-20 C (prevent cross-linkage formation in muscles so that they dont contract)
what are some pre-slaughtering conditions?
Keep animal calm and relaxed before slaughter
What meat will a stressed animal result in?
dark-cutting beef, that is darker in color and has a higher pH
if the animal was stressed or excercised before slaughter
- glycogen is depleted in the muscles, and
- less lactic acid will produced during rigor mortis
What is dry aging?
a method of tenderizing meat, using protease(an enzyme) to break down the muscle fiber, the meat is hung in a fridge at 1 C-3 C for 1-6 weeks
20% of the original weight (mostly due to
dehydration) is lost, intensifying meat flavor
!!However, the dried or spoiled exterior layer have to be trimmed.
What is wet aging?
similar process to dry aging except the meat is vacuum sealed and refridgerated at 1-4 C for 1-6 weeks
What are the benefits of wet aging?
shorter time if done in a warm temp (~21 C for 2 days prior to refridgeration and fast aging, UV is used to inhibit microbial growth
methods of tenderizing meat?
- enzymes (breaks down muscular proteins but commercial tenderizer only work for thin cuts, alternatively a more effect tenderizer is injecting a solution into the animal 10 min before slaughter
- electrical stimulation (speeds up rigor mortis, and accelerates enzyme activity to disrupt the protein structure)
- high pressure process (meat is subjected to high-pressure shock wave, chages native structure)
- Salts (seasons meat and improces juiciness by increased water holding capacity)**calcium chloride and ammonium hydroxide leads to tenderization but has an off-flavor
- Acid & alcohol (disrupts hydrogen bonding in connective tissue)
- mechanical tenderization: pounding and needling meat to physically break the muscle and connective tissue, but this will reduce juicines
- Grinding: usually low quality meat is processed and used to create things like burger patties
what are some exampes of enzymes for tenderization
(papain from papaya,
bromelain from pineapple,
ficin from figs,
rhyzyme P-11 from fungi)
effect of freezing on meat quality?
increases shelf life, but lower water holding capacity, loss of cell juice when thawed, intracellular enzymes are released and can catalyze unfavourable reaction
Why does overcooked meat become dry and tough?
proteins coagulate(lowers water holding capacity), water is lost by evaporation
how can tenderness be improved during cooking?
more fat in meat, dry heating methods for tender cuts (high temp, short cooking time), moist heating method for less tender cuts w/ high collagen content (low temp, long cooking time)
What causes the cracks in meat when cooked?
protein coagulation
purpose of curing meat?
preserving meats (decreasing water content inhibits microbial growth) popular ingredients used to cure meat potassium/sodium nitrate and sodium chloride
what happens during curing process?
decreased water content prevent microbial growth, nitrate converts to nitrite, and reacts with myoglobin to form the red color nitrosylmyoglobin (that can help with inhibit bacteria)
