Transcript Meat - Marblehead High School

Meat
Consumption
 Red meat consumption has decreased
from 145 lb per person in 1970 to 116 lb
per person in 2005
 Beef consumption decreased from 84 lb
in 1970 to 65 lb in 2005
 Increase in use of mixtures containing
mainly meat, poultry or fish (hamburgers,
frozen dinners, chili)
 Decrease in use of separate cuts of meat
such as steaks and roasts.
Nutritive Value
 Protein - high quality
 Fats - mostly saturated, cholesterol
 Vitamins - good source of thiamin,
riboflavin, niacin, vitamin A. Thiamin may
be lost by heating
 Minerals - good source of iron, zinc,
phosphorus. Minerals may be leached in
cooking.
 Muscle
Structure
Muscle fibers are long thin structures
ensheathed by a delicate membrane, the
sarcolemma. Contractible matter made of
myosin and actin which combine in contraction
to form actinomycin. Myosin forms thick
filaments and actin forms thin filaments. ATP
provides energy for the process.
_____ _____ _____ _____ _____
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_____ _____ _____ _____
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 Connective tissue
Muscle fibers are bound by connective tissue,
provides support.
Endomysium - surrounds individual muscle
cells
Perimysium - surround a bundle of fibers
Epimysium - surrounds bundles
1. Collagen - found in tendons. Hydrolyzed to
gelatin in water and becomes tender.
2. Elastin - found in ligaments
3. Ground substance - mucopolysaccharides
Amount of collagen in meat effects tenderness
 Fat
1. Fatty tissue or cover fat
2. Marbling - intramuscular fat
 Bone
May help identify location on carcass.
Tender cuts from back of animal, less
active muscles. Examples: rib, t-bone,
wedge. Less tender cuts from
shoulder and hip, more active muscles.
Examples: blade and round bone
Tenderness of Meat
 Amount of connective tissue - collagen
 Fat, marbling - layer of fat insulates
carcass, delaying chilling, thus
metabolic changes occur. Some
research shows no definite relation of
fat to tenderness.
 Low voltage electrical stimulation - more
postmortem metabolism
 Tenderizing
Tenderizing Techniques
1. Enzymes - digest proteins and cause
tenderization: papain, bromelin, ficin.
Caused by general hydrolysis.
2. Mechanical - pounding, grinding, cubing.
Accomplished by breaking fibers.
3. Acid - hydrolyzes proteins such as a
marinade.
4. Salts – retain moisture and break down
compounds surrounding muscles which
causes the release of protein
5. Hydration of connective tissue by
cooking in moisture
Color
 Heme proteins: hemoglobin and myoglobin
give red color. Combine reversibly with oxygen
 Fresh meat
O2
Myoglobin <-> Oxymyoglobin <-> Metamyoglobin
Purplish red
Red
Brown
Metamyoglobin caused by oxidation of iron.
Increased by denaturation of protein by freezing,
salt, or UV light
 Cooked meat
heat
Oxymyoglobin ---> denatured globin
denatured globin hemochrome
Red
Gray-Brown (tan)
 Cured meat
nitrite
heat
Myoglobin ---> nitroso-myoglobin --->
Purplish red
Red
oxidation
denatured globin
<--->
denatured globin
nitrosoreduction nitrosohemochrome
hemichrome
Pink
Brown
Types of Meat
 Beef
Tenderness depends on muscle,
connective tissue, fat and bone. Color:
purplish red or cherry red
 Veal
More collagen and elastin than beef. Low
fat but moist heat not always needed as
animal is young, tender, and juicy. Color:
lighter red, pinkish tinge around bones
 Lamb
Young animal, tender. Better roasted
than seared as high heat may toughen
muscle tissue. Color: darker, deeper
red than beef
 Pork
Usually tender, best when roasted in
open pan without water at 325 F. Color:
dull rose
Inspection and Grading
 USDA is responsible for inspection,
grading, and setting of standards.
 Government inspection
Required of all animals that enter
interstate commerce. Animals
inspected alive and at various stages in
slaughtering process. Strategy includes:
HACCP plan, written sanitation
standard operating procedures, tests for
Salmonella on raw meats and tests for
generic E. coli.
 Grading
Quality grade - based on maturity,
character of lean (color, firmness,
marbling).
Yield grade - based on cutability which
indicates the proportionate amount of
salable retail cuts from a carcass.
Storage
 Cold storage is required as meat is highly
perishable.
 Best if stored below 36 F or at least
refrigerator temperatures. Maximum
refrigerator storage is 3-5 days, however,
ground or variety meats should be used in
1-2 days.
 Should be wrapped as not to absorb odors
from surrounding foods.
Meat Cookery
 Dry heat - used on tender cuts of meat
that contain a high proportion of muscle
tissue. Examples: roasting or baking,
broiling, pan-broiling, pan frying, deep fat
frying.
 Moist heat - used for less tender cuts of
meat that contain more connective tissue
like collagen and elastin which soften in
moisture. Examples: braising, stewing,
boiling, pressure cooking and slow
cooking.
Cuts of Meat
 Most tender cuts
Rib, T-bone or loin, and wedge or sirloin
 Medium tender cuts
Chuck or arm - shoulder area, rump - hind
leg area, and round
 Least tender cuts
Flank, plate, brisket, neck, shank
Bones and Retail Cuts of Meat
 Rib bone-rib steak, standing rib roast, rib
eye roast
 T-bone-T-bone steak, NY strip steak,
porterhouse steak, loin roast, loin chop,
tenderloin
 Wedge bone-sirloin steak, sirloin tips
 Round bone-round steak, top round,
bottom round, cubed steak
 Blade bone-blade steak, blade roast,
shoulder steak, shoulder roast, arm roast,
or arm steak
Power Point Authors
Jon Christiano
&
Dr. Jane Ross
The University of Vermont
Foods and Nutrition
Basic Concepts of Food