Classification of proteins

Simple proteins

Contain only amino acid in their structure, include animal and plant proteins

Conjugated proteins

Consists of a protein combined with a non protein e.g. haemoglobin

Derived proteins

Formed due to chemical or enzyme action on a protein e.g. enzyme rennin digests caseinogen to produce casein

Simple

Animal; Fibrous, globular, collagen, ovalbumin, in connective tissue of meat. Plant; glutenins, gluteninzein , wheat, maize

Conjugated

Lipoproteins, prolamines, lecithin, egg yolk

Animal proteins

Cheese ( Casein ) Milk ( Caseinogen ) Egg white ( Ovalbumin ) fish ( Collagen) Red meat ( Actin )

Plant proteins

Wheat ( Gluten ) Soya beans ( Glycinin )

Low biological value

Lack some essential amino acids, from plant sortes

High biological value

Contains all essential amino acids required, generally from animal sources

Supplementary Value/ Complementary Role Of Protein

The ability of protein foods to make good the deficiency of another, when LBV foods that lack essential amino acids are together they can provide all the essential amino acids only if the deficiency of one essential amino acid missing one food can be made up for by being present in the other food

Structural proteins ( specific function )

Growth and repair of body cells, helps to form cell membranes, muscle, tissue and skin

Structural proteins ( deficiency )

Delayed healing of wounds

Physiologically active proteins ( specific function )

Production of enzymes, hormones, antibodies, nucleoproteins such as chromosomes

Physiologically active proteins ( deficiency )

More susceptible to disease, malfunctioning of body organs and systems

Nutrient proteins ( specific function )

Source of essential amino acids, energy source when carbohydrates and fat reserves are low

Nutrient proteins ( deficiency )

Lack of energy, severe deficiency can lead to kwashiorkor and marasmus

RDA value of protein

Children=30-50g, Teenagers/adolescence=60-80g, Adults/elderly= 50-75g