topic 12 meat and porty Flashcards
Three kinds of connective tissue
Collagen: white, not as flexible/elastic as elastin
Elastin: yellow, elastic
Reticulin: very small fibres, forms a delicate network around muscle cells
Softer fats has a higher percentage of unsaturated fatty acids
ture
Fat may be more yellow because
Animal feed
Animal is older
different types of fat tissue
intramuscular
Intermuscular
Subcutaneous
what kind of fat is called marbling?
intramuscular
what is intermuscular fat like?
Between individual muscles
“Seams” of fat
what is subcutaneous fat
Found under skin, may be trimmed before sale
how could Bones help to identify retail cuts of meat
Back or Chine bone
Young animal – bone is red and less hard
Mature animal – bone is white and hard
main pigment in the meat
myoglobin
difference between myoglobin and hemoglobin
myoglobin is smaller
myoglobin holds O2 in muscle, hemo, carries o2 in the blood
pigment in meat, darker in older animal
what’s the color of oxymyoglobin?
bright cherry red
what’s the color of deoxymyoglobin?
purple-red
color of metmyoglobin?
brown
what is metmyoglobin?
when myoglobin is holding water, Fe2+ Ferrous turns into Fe3+ ferric
REMEMBER: color is Not necessarily an indication of spoilage
REMEMBER:Temperature is best indicator of doneness NOT colour
color is Impacted by the presence of oxygen and exposure to light
classification of veal
From immature cattle of at least 3 weeks and less than 20 weeks of age
classification of lamb
young animals less than 12 months of age
yearling mutton
greater maturity than lamb, about 12 months old
mutton: passed lamb stage, not usually sold
pork?
Comes from swine, young animals 6 to 7 months old
Postmortem Changes
Rigor mortis – stiffening of carcass occurs due to metabolic changes
why would rigor mortis occur?
Loss of ATP and The accumulation of lactic acid in the muscles
Factors that impact rigor
Temperature,
species of animal, in larger animals it stay longer
age,
activity before slaughter: if too nervous,
why meat product need aging?
Holding of meat after rigor mortis is resolved
u Beef – often aged for 11-14 days
u Lamb – may be aged
u Veal – not improved with aging
how would aging help meat product?
Increased tenderness
Improved flavor and juiciness
methods of agingmeat
Wet Aging: meat is packaged in a vacuum bag and held under refrigeration
Dry Aging: aged “as is” under refrigeration
what is Case-Ready Meat Packaged centrally and then delivered to retail stores
Vacuum packaged, reduces oxygen: purple-red colour until opened
High-oxygen modified atmosphere: often sold on a tray covered with clear film, meat is bright red but will brown over time due to high oxygen levels
Carbon monoxide, low-oxygen modified atmosphere: shelf life is usually longer compared to other methods, meat will remain a bright red colour for longer
Primal or Wholesale Cuts and Retail Cuts
First major division of the carcass
Further divided into retail cuts
Division of cuts is made in relation to bone and muscle structure
The shape and sizes of bones and muscle in retail cuts act as a guide to identification
restructed meat
Involves flaking, coarse grinding, dicing, or chopping the meat
Ingredients added to promote binding
Meat formed into desired shape and size
Variety Meats
Sweetbreads:thymus or pancreas of a young animal
Heart
Tongue
Tripe毛肚stomach
Liver
Kidney
Oxtail
amount of fat in extra lean ground beef
Extra Lean 7.5g/100g
Tenderness of the meat
Depends on:
u Animal maturity
u Postmortem aging
u Muscle type
u Marbling
u Marinating when prepared
u Mechanical tenderization
u Proper cooking methods
u Degree of doneness
limit of fat in ground meat
no more than 30%
Mechanical tenderization
Grinding / Cubing
Tenderizing compounds
Enzymes including proteinases
Papain, bromelin, and others
papain?
from papaya
bromelin?
from pineapple
actinidin?
from kiwi
flavour of the meat
1.Flavor developed by cooking
2.Chemistry of meat flavor
Volatile and nonvolatile compounds
what would influence the falvour of the meat?
Flavor influenced by:
Feed of cattle: grass or grain
Time and temperature: serving temperature
Reheating – “warmed-over flavor”=oxidized fat
Cured Meats: Ham, bacon, corned beef, frankfurters, sausage, and others
Originally used as a method of preservation for meats
Curing ingredients
Sodium Nitrite硝酸盐
Sugar
Salt
Seasonings
Cured Meat Pigments
1.Nitrite + myoglobin = Nitrosylmyoglobin pink
2. salt+meat=pink
3.Cured meat pigments are reactive to lighting and may discolor in
lighted display areas
Nitrites/Nitrates in Meat, Is It Safe?
toxic, but amount matters
how to avoid ground beef food safety risks caused by E.coli or
Cook to 155°F (68°C) to 160°F (70°C)
REMEMBER:Brown color is NOT a reliable indicator meat was cooked to a safe
temperature`
Pork, beef, veal or lamb steaks or roasts
Cook to 145°F (63°C), avoid Potential risk of Trichinella spiralis in pork
Methods of Preparation
Dry:Roasting, baking, broiling, and pan-broiling
Moist:Stewing, cooking in water, pressure cooking Less tender cuts of meat
Combination: Braising
Effect of Heat on Meat
pH and the color of the meat
Higher the pH ，darker the color
