Meat has exerted a crucial role in human evolution and is an important component of a healthy and well balanced diet due to its nutritional richness. From the nutritional point of view, meat's importance is derived from its high quality protein, containing all essential amino acids and it's highly bio available minerals and vitamins.

1. Meat Composition And
Nutrition
Ashir Azeem

2. Introduction
Nutrients in meat vary with animal breed, feed, season and
position of meat cut. Meat contains approximately 75 %
water, 19 % protein, 5 % fat with small portion of
carbohydrates, free amino acids, dipeptides, nucleotides
and minerals.
Generally, low fat contents in lean red meat, have less
cholesterol level and essential vitamins and minerals.

3. Meat is an excellent source of protein as well as water soluble
vitamins and minerals which provide 25 % recommended
dietary intake (RDI). Almost 10 % RDI is achieved from
riboflavin, pantothenic acid and selenium.
The mixture of muscles (84 %), gelatin (16 %) and
nitrogen has biological value of 99 whereas biological value
of beef is 92 in comparison to biological value (100) of egg
protein.

4. Water
Water is the most variable component in meat. Its contents
are inversely related to the fat but in lesser extent with ash
and carbohydrates value.
Water contents declines when the animal reaches to the
chemical maturity without considering the species of animal.
As animal matures, fat content increases while a significant
decrease in water content occurs

5. This inverse relationship does not affect the bone content
occurs. This inverse relationship does not affect the bone
content. Its percentage varies from low (4.5 %) to high
(64.5 %).
From the kidney knob low water containing meat is obtained
whereas over the rib high fat containing meat is obtained.

6. Protein and amino acids
 Protein are made up of almost 20 amino
acids that may be essential and non-
essential.
 Amino acids have a general structural
formula:

7.  Meat contains essential health promoting constituents like
protein, fats, micronutrients, and omega-3 fatty acids.
 Proteins play a wide range of functions that may be
structural, contractile, or enzymes which catalyze the
chemical reactions. Proteins contain carbon nitrogen, oxygen,
hydrogen and sulphur compounds.

8. Meat and meat proteins are further divided into different fractions:
a) Sarcoplasmic Proteins
Sarcoplasmic proteins are also referred to as soluble proteins
because they are extracted through water or low ionic salt
concentrations.
Sarcoplasmic plasmic proteins contain mitochondrial
oxidative enzymes, flavin compounds and heme pigments.
These posses lyzozymes or nucleoproteins which play a vital
role in degrading the waste material and are also helpful in
synthesis and deposition of proteins.

9. b) Mayofibrillar Proteins
 The major component of meat muscle is myofibril that
covers meat about 70 % by volume. Three dimensional
structures of filament of the myofibrils provide an open space
for water to be immobilized.
These proteins are also known as contractile proteins
because they play role in muscle contraction.

10. c) Connective Tissue proteins
Connective tissue proteins considered as a supporting
framework thus plays numerous functions in living body.
This fraction of proteins includes collagen, elastin and
reticulin, which is less well-defined than the former two.

11. i) Collagen
Collagen is the important fraction of connective tissues which
comprises of 20 to 25 % of the total protein content. It is
widely present in the body. Collagen is the triple helix of
peptide chains coiled with one another to form a single fiber.
Collagen is the important protein present in bones, skin and
tendons.

12. ii) Elastin
Elastin belongs to an unreactive and unique class of proteins.
It is a minor component of most tissues, but found in
appreciable amounts in the ligaments of the vertebrae and in
the walls of large arteries.

13. iii) Reticulin
It is chemically similar to collagen and many researchers
believe it to be merely another form of collagen.
Reticulin fibers are fine, wavy and show some branching.

14. Carbohydrates
 Immediately after postmortem, muscle containing small amount (about
1 % of glycogen usually disappears before completion of rigor.
 Both the rate and amount of glycogen breakdown control the physical
properties of meat, such as water-holding capacity, color, and
tenderness.
 Rapid glycosis, while the muscle temperature is still high, has been
shown to be a causative factor in development of Pale, Soft and
Exudative (PSE) muscle in the pig.

15. Similarly, freezing before completion of glycosis has been
found to cause excessive muscle shortening, thus contributing
to toughness in meat.
And if the glycogen and creatine phosphate are all used up
before the pH reaches the normal of 5.3 to 5.6, the final pH of
meat remains on higher side. The resulting high pH meat is
called commonly called “dark cutting” because of its dark
appearance and low oxygen uptake.

16. Fat tissue is made up of fat cells embedded in a matrix of
connective tissue.
Animal fat is composed of neutral fat and phospholipids. The
neutral fats are glycerol esters of straight chain carboxylic
acids and triglycerides.
Triglycerides are present as single or mixed depending on the
three fatty acids esterified to the glycerol are same or
different. The structural formula represents that all three R-
group containing three different or same groups.

17. Phospholipids are present in animals in form of
phosphoglycerides. These are found in very minute range
from 0.5 % to 1.0 % of lean muscle.
Triglycerides are more stable than phospholipids, they are
readily oxidized and give off flavor to the meat and meat
products.
Major contribution of energy comes from fat that is about
2.25 times more than protein and carbohydrates.

18.  Fatty acids play an important role in maintaining health. Linoleic acid
plays a key role in controlling and showing positive anti-carcinogenic,
anti-atherogenic, anti-obesity and anti-diabetic effects.
Different sources of fat are helpful in controlling diseases and
stimulating interest or arising awareness in people.
40 % of total fatty acids in the lean meat and 48 % with fat
meat from a saturated fatty acid portion.
Meat is a frequent source of long chain ω-3 PUFAS. The
unsaturated fatty acids, linoleic (C 18:2), linolenic (C 18:3)
and arachidonic (C 20:4) appear to be essential. They are
necessary constituents of cell walls, mitochondria and other
intensely active metabolic sites.

19. Vitamins
Meat can be regarded as an important dietary source of
vitamins, including B1 and B2 as compared to vitamin D.
Factors like nature of organ, species and age of animal affect
the vitamin content. Organ meat possesses markedly higher
concentration of vitamin (A and B12) than muscular tissue.
Vitamin level in lean meat tissue is low but is excellent
source of folate and vitamin A.
Bioavailable vitamins in rich amount can be obtained from
meat. e.g. Vitamin B12 2/3 as part and 25 % RDI of
riboflavin, niacin, vitamin B6 and panthothenic acid,
fulfilling daily requirements in a 100 g serving of meat.

20. Minerals
 Mineral components vary in several meats. Potassium is quantitatively
the most important mineral, followed by phosphorus, except in cured
meat where sodium from the added salt predominates.
 In respect of species differences, the high content of iron in beef no
doubt reflects the greater concentration of myoglobin in this species
than in mutton.
 Iron, copper and zinc contents of kidney and liver are much higher
than those in muscular tissue.

21. Bioactive Compounds
Along with the essential nutrients that have defined requirements, the
beneficial effects of a lot of meat based bioactive substances.
a) Taurine
Taurine is an amino acid in meat which is of high importance. Meat is a
high source of taurine at the rate of 110 mg per 100 g in lamb meat and
77 mg per 100 gram in beef.
b) Carnitine
Long chain fatty acids are transported across the inner membranes of
mitochondria, by L-cartinine beta-hydroxyl-gamma-trimethyle amino
butyric acid), to produce energy while exercising .

22. c) Conjugated linoleic acid (CLA)
CLA can play an important role in control of obesity by the antioxidants
and immunoregulatory properties that it possesses. It is abundant in the
fat component of the red meat that is 1g/100g.
d) Creatine
There is an important role played by creatine and its phosphorylated
derivatives, in muscle energy metabolism and in some conditions its
supplements can increase muscle performance. Red meat has about 350
mg per 100 gram.