Let's Talk About Meat

TYPES OF MEAT

            The main meats eaten in the UK are:

                        Beef                Mutton

                        Veal (calf)       Pork

                        Lamb               Bacon

STRUCTURE AND COMPOSITION

            Lean meat is composed of the muscles that move the body in an animal. Muscles are composed of cells in the form of long, slender fibers. The size of muscle fibers affects the tenderness of cooked meat.

            Slender – small fibers are associated with tender meat.

            Large – long fibers are associated with tougher meat. Muscle fibers increase in size as the animal gets older, so the older the animal, the tougher the meat from it. The parts of the animal’s body that do the most physical work is neck, skin, forearm have the largest muscle fibers and so make tougher meat.

            Whole muscles are attached to bones by tendons. Connective tissue is made of two proteins, collagen and elastin.

Ø  Collagen is the main component of tendons, ad the connective tissue surrounding muscles, particularly muscles, particularly those that do the most work. Collagen is less flexible than elastin, and when heated in the presence of moisture, it is converted into soluble gelatine, which greatly increase the tenderness of connective tissue and therefore of the meat.

Ø  Elastin is a main component of ligaments (in between bones) and has the ability to stretch and return to its original shape. It is an insoluble and tough protein, but there is less elastin than collage in muscles, so it does not have a major influence on the toughness of meat.

“The two main protein of muscle fibers”

1.      Myosin

2.      Action

Fat

            In meat, fat is found in the following places:

            Under the skin in a adipose tissue, around vital organs, e.g. kidneys (suet) between bundles of muscle fibers(invisible fat).

            Fat under the skin may be yellowish in color, because of the presence of carotenes from plants, depending on what the animal was fed on, between the bundles of muscle fibres gives the meat a “marbled” effect. Marbling in lean meat is an important requirement when the meat is graded and large amounts of feed are required to produce. This is one of the reasons why lean meat is so expensive.

            This content of meat helps to give flavor, moisture, and texture to the cooked meat.

COLOUR OF MEAT

            The colour of meat is mainly due to the presence of myoglobin, which is a purple/red tissue protein, and haeglobin from the blood, some of which is left in the meat after slaughter.

            When oxygen is taken to the tissue, the myglobin is converted to (oxygen) oxymyoglobin which is bright red. After slaughter, the meat remains dark oxygen in the air, when it becomes bright red.

            When fresh meat is stored for a few days, its colour changes to a brown/red, due to the formation of metmyglobin. This does not seriously affect its palatal\bility when cooked. If storage is continued. The meat may become green/brown through the effects of enzymes and bacteria. This will spoil the palatability.

CHOOSING MEAT

            As meat is an expensive food, it is wise to choose it carefully, considering the following factors:

            Value for money

1.      There should not be too much bone in joint as this reduces it value for money. However, some is needed to produce flavor when cooking.

2.      Cheaper cuts of meat, which are generally tougher, are just as nutritious as more expensive, leaner cuts. If cooked well, they can be made into appetizing and nutritious meals.

3.      There should not be too much visible fat on the joints.

APPEARANCE

            Meat should have the following physical characteristics:

1.      Colour

2.      It should be moist but not dripping

3.      it should smell fresh.

4.      Lean meat should have a marbled appearance.

5.      It should be slightly springy to the tough.

INTENDED USE

1. Allow for possible shrinkage during cooking when choosing a joint.
2. It is uneconomic to use expensive, lean joints of meat for stewing or casseroling.
3. As a general guide, allow about 100g of meat per person, unless it is for a dish such as risotto where vegetables, cereal grains, or pulses from a major part.

THE EFFECT OF HEAT AND CHANGES DURINGCOOKING

            Texture and tenderness

            The proteins of meat denature at temperature of 40C to 65C. As the proteins denature, the structure of the meat tightens and the meat becomes firmer.

The collagen id\s converted to gelatine in the presence of moisture which greatly increases the tenderness. The elastin is only softened slightly.

            Meat can partially tenderized before cooking by:

1. Mechanically founding, scoring, and cutting across the muscle fibres to reduce their length.
2.  The use of enzymes, such as papain (from the pawpaw plant) which partially digest the protein.
3. Marinading in vinegar or alcohol.

FAT

            The adipose tissue becomes mare tender when cooked. The fat melts, and penetrates the lean meat during cooking, which increase the energy value of the lean meat. The fat content may also make the meat appear more juicy. On the roasted meat, the fat becomes crisp and brown.

COLOUR

            During cooking, the colour of meat changes from red to brown, due to the oxymyoglobin being converted to haemochrome.

FLAVOUR

            Cooking meat improve its palatability. In dry cooking methods, extractives containing flavour are squeezed out of the meat on to the surfaces as the protein denature and shrinks.

Nutritive value

            Protein, the nutritive value of protein in meat is little affected in normal methods of cooking. But, if overcooked, they become less digestible.

            Vitamins, the fat-soluble vitamins remain stable, but the water-soluble B vitamins may be leached into the cooking liquid in moist methods of cooking. Thiamin is particularly heat sensitive and may be destroyed in dry methods of cooking.

            Minerals, there may be some leaching of minerals into the cooking liquid in moist methods of cooking. The liquid should be served with the meat.

THE IMPORTANCE OF MEAT IN THE DIET

            Meat is an important food as it is good source of protein, B vitamins, iron, and zinc. It is a main source of high biological value protein for many people. The nutritional value of lean meat of most types is on average.

            Protein             2%                   Minerals          1%

            Fat                   5%                   Water              74%    

            The minerals found in meat include iron and zinc. Meat also contains B vitamins in useful quantities, and pork is a particularly good source of thiamin.

            Both the protein and fat in meat are readily digested and absorbed in the body.

USES OF MEAT IN FOOD PREPARATION

            Meat is used in a vast range of recipes all over the world. The various cuts of meat are used for different purposes, according to their suitability for each cooking methods.

BSE

            BSE (Brovine Spongiform Endephalopathy) or ‘man cow desease’ is a fatal disease which attacks the brain and spinal cord of cattle. T\It was first identified in the UK in 1986.

            Some health experts are concerned that a form of BSE could be transferred to humans if they eat the meat of affected animals, although this is by no means certain. Since 1988, very strict measures have been in place in the UK to control the disease and make sure that the meat from affected animals does not enter the food chair.

            The cause of BSE in cattle is clear, but it is thought tat using brain and offal from sheep in cattle feeds may have been the prime factor.