Transcript MEAT - Food and Nutrition @ JVS [licensed for non

MEAT
Structure
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Meat is the flesh of animals reared for food. E.g.
cows, goats, pigs.
Meat is composed of bundles of muscle fibres joined
by strong connective tissues with fat scattered
between.
The main protein in muscles is myosin and actin.
Connective tissues contain the protein collagen and
elastin.
Types of Meat
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Beef: Cow, cattle
Mutton: Goat, sheep
Pork: Pig
Veal: Calf
Venison: Deer
Offals
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edible internal organs of animals
E.g.: brain, kidney, heart, liver, tripe, tongue
Very good source of
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iron and vitamin B12 (liver and kidney)
Vitamin A (liver)
Glycogen (liver)
Nutritive Value
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Protein: Myosin, globulin collagen (in connective tissue)
Fats: particularly lamb, pork and beef, gives flavour,
moisture and texture. Some fats are found between
muscle fibre of lean parts of meat. This is known as
marbling.
Vitamins: a good amount of B group vitamins
Minerals: A good amount of iron and phosphorus.
Cholesterol
Water - 60%
Factors to consider when
choosing meat
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Good characteristic colour
No unpleasant smell
Firm and elastic to touch, moist but not wet.
Grain should be fine and even.
Avoid too much bone, gristle or fat
What makes meat tough or tender?
1. Age
 In young animals, the muscle fibres are short
and finer. Meat is tender.
 As the animal matures, the muscle fibre
thickens and there is more connective tissues.
Thus the meat from the older animals is
tougher than the meat from young animals.
 There is also more fat in older animals.
What makes meat tough or tender?
2. Part of the animal
 Meat from the leg is usually tougher than
meat from the ribs because the leg muscles
work harder.
 The more the animal works the muscle, and
the tougher it will be.
What makes meat tough or tender?
3. Fat distribution
When fat is evenly distributed throughout
the muscle, the meat is usually more
tender and of a better flavour than meat
that has concentrated visible deposits of
fats.
What makes meat tough or tender?
3. Fat distribution
Methods used to tenderize meat
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Mincing or grinding
Cubing, slicing - Cut meat across the grains.
Pounding with a meat pounder or the blunt edge of a
cleaver
Sprinkling with commercial tenderizer e.g. papain
(papaya)
Marinating e.g. Soya sauce, acids (lemon juice, vinegar,
tomato) yoghurt, wine.
Cooking slowly with water e.g. stewing, boiling.
(Collagen in the connective tissue changes into gelatin
which dissolves in the water. This causes the meat to
come apart easily.)
Reasons for cooking meat
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To kill any harmful bacteria
To make it tender and more digestible
To make it look, taste and smell more appetizing
To preserve food for later use
To develop extractives for flavour
Effect of heat
Dry heat
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Protein starts to coagulate at 60°C
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Red meat changes to brown
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Fats melts and goes crisp making meat juicy
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Meat shrinks as protein coagulates and shortens.
- If meat is overcooked, juices are squeezed out
onto surface, which might then dry out.
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Connective tissues (containing collagen) becomes
tougher.
Effect of heat
Dry heat cooking (roasting, baking,
grilling) is best for tender meat which has
little or no collagen and elastin. The
elastin will contract during cooking,
squeezing out the meat juices causing the
meat to be dry.
Effect of heat
Moist Heat
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Protein starts to coagulates at 60°C when outer layer is
sealed lightly.
Red meat changes to grayish brown.
Fat melts partly and seeps into the gravy.
Meat shrinks a little. The longer the cooking, the greater
the shrinkage. Juices tend to come out of the meat into
the gravy, developing a rich flavour in the gravy, with
slight loss of flavour of meat.
Collagen in connective tissue is converted to gelatin.
Overcooking results in the meat falling apart.
Effect of heat
Moist heat method (boiling, stewing,
frying) is recommended for cooking
tough meat as it is a slow process.
Which is more difficult to digest?
Meat
Or
Fish
Meat is more difficult to digest than
fish.
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Fish has no elastin (the wall of muscle fibre, very
tough, cannot be changed by cooking but can be
broken down mechanically or removed)
Fish consists of short, fine fibres, bound together
by a small amount of fine connective tissue.
Ways to reduce fat content in meat
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Use more poultry, reduce consumption of red
meat
Avoid frying. Grill or bake instead
Remove fat before cooking
Marbling of fats in beef