The word 'protein' was oined by Jon's Jacob Berzelius in 1838. For the previous 150 years, however there had been the concept of an ' animal substance' slight variants of which were thought to make up muscles, skin and blood. Proteins are essential for the human body. There is no life without protein. The efficiency or degree to which dietary proteins can be used for building parts of the human body is determined principally by the type and relative amounts of the Amino acid present in the particular protein molecule. They are one of the building blocks of body tissue and also serve as a fuel source.
Protein is essential for the growth and repair of the body and maintenance of good health. The amount of protein we need are changes during the life time. Different food contains different amount and different combinations of amino acids sequences (British nutrition foundation,2012). Protein is one of the nutrients along with carbohydrates,fats, vitamin, mineral and water are the important components.As a fuel, they provide as much energy density as carbohydrates: 4 kcal (17 kJ) per gram whereas lipids provide 9 kcal (37 kJ) per gram. Dietary protein is considered an important macronutrients, ideally contributing 10-15%to the total energy supply. Protein is considered the most effective macronutrients in thermogenesis via the regulation
Aside from water, proteins are the most abundant kind of molecules in the body. Protein can be found in all cells of the body and is the major structural component of all cells in the body, especially muscle.This also includes body organs, hair and skin. Proteins are also used in membranes, such as glycoproteins. When broken down into amino acids, they are used as precursors to nucleic acid, co-enzymes, hormones, immune response, cellular repair, and other molecules essential for life. Additionally, protein is needed to form blood cells.(Harmann