Protein constitutes 10-15 per cent of the energy in almost all human diets. It is also important in the structure of all cells in the body, as well as forming enzymes, molecules that transport substances in the blood and some hormones.
The problem of providing adequate protein for an expanding world population is a second only to the overall food problem.
Apart from their nutritional significance, proteins play a large part in the organoleptic properties of foods.
Proteins exert the controlling effect on a texture of foods from animal sources.
Foods in meat, poultry, dry peas and beans, eggs, ad nuts group and in the milk, yoghurt and cheese group contribute an abundance of high quality protein.
Two others, the vegetable group and the grains group, contribute smaller amounts of protein, but they can add up to significant quantities.
Protein content of wheat and flour is considered one of the best single indices of bread making quality.
Protein often occurs in foods in physical or chemical combinations with carbohydrates and lipids.
The glycol proteins and lipoproteins affect the rheological properties of food solution or have technical applications as edible emulsifiers.
During the heating (boiling, baking or roasting) the amino acid side chains are degraded or interact with other food component (e.g. lysine with reducing sugar) to give typical flavor.
Excessive heating may, on the other hand, reduce nutritive value.
The protein quality of the diet determines, in large part, how well children grow and how well adults maintain their health.
High quality protein provide enough of all the essential amino acids needed to support the body’s work, and low quality proteins do not.
Two factors influence protein quality – the protein’s digestibility and its amino acid composition.
Food Proteins
