Chemistry in the Meat Industry Food Technology

The meat industry is concerned with turning an animal carcass into many different end-products.

These end-products are derived from all parts of the animal (muscle, bone, fat, cartilage, skin, fluids and glands), and are produced through a range of physical, chemical and biological processes.

The Composition of Meat
Meat is composed of, in descending order, water, protein, fat, other water-soluble organic material and water-soluble minerals. The fat portion includes some fat-soluble substances, including some vitamins. Meat is an important source of amino acids (the building blocks of proteins), minerals and vitamins, as well as being a good source of energy.

Biochemical Changes: From Muscle to Meat
The most significant change occurring on death is that circulation stops, with the result that oxygen is no longer sent to the animal cells. This means that reactions begin to take place there under anaerobic conditions. One of the major consequences of this is that the pH decreases, because in the absence of oxygen glucose is converted to lactic acid rather than CO2 and H2O.

This tenderises the meat, so research is being done into ways to maximise this effect.

The Importance of Myoglobin
Myoglobin is the major pigment in meat. In different environments it has different forms, each with a slightly different colour, e.g. in cured meat it is pink, in very fresh meat it is purplish-red, and in meat that has been exposed to the air it is bright red. By changing the environment in which meat is stored and packaged, the colour of the meat can be controlled.

Three components of an animal carcass with specialty value are the fat, collagen and glands.

Fat
The fat (lipids) is an important source of energy. The lipids can be used as is for animal feed, or processed to make tallow for margarine manufacture or free fatty acids and glycerol for soap manufacture. Anti-oxidants (e.g. vitamin E) prevent the fat from going rancid.

Collagen
Collagen is a fibrous protein found in the bones, teeth, skin and connective tissue of animals. It is the portion of skin used to make leather, and also the portion of the intestines used to make sausage casings. If it is reacted first with alkali and then with hot aqueous acid its structure breaks down to form gelatin.

Glands
Many animal glands can be processed to make pharmaceuticals, e.g. adrenalin, a heart stimulant, is commonly extracted from the adrenals of cows.

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