Proteins

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             Proteins are essential biomolecules which found throughout the body (in muscles, bones, skin, hair and all other body parts and tissues. These are main constituents of all living cells and play an important role in the growth and development of cells and tissues. It makes up the enzymes that power many biochemical reactions and the hemoglobin that carries oxygen in your blood.

                      Proteins are made of many small units called amino acids. Carbon, hydrogen, oxygen and nitrogen are main constituent elements of the proteins.

Sources of Proteins:

             Protein is a key part of any diet. We obtain proteins from both plants and animals. Some important sources of proteins are followings:

Plants as source of proteins:

           We get proteins from many plants. Eating legumes (beans and peas), nuts (cashews, walnuts), seeds (pumpkin seeds, sunflower seeds, flax seeds, sesame seeds), whole grains (wheat, rice, millet). Other than these many vegetables and fruits contain some level of protein.

Animals as source of proteins:

           Animal products tend to contain higher amounts of proteins than plant foods. Dairy foods (yogurt, milk, cheese), poultry products (chicken, eggs) and meat is good source of proteins.

 

Test for Presence of Protein in Food:

Required materials: – Test tube, test tube holder, distilled water and food item to be tested.

Required chemicals: – Sodium hydroxide (caustic soda) and copper sulphate (blue vitriol) solutions.

Procedure: –

    1. Take a cleaned and dried test tube.
    2. Add small amount of food sample into the test tube. If food sample is solid, then first grind or mash it and make a paste.
    3. Add 2-5 drops of copper sulphate solution and 10-15 drops of sodium hydroxide solution by using dropper.
    4. Shake the test tube gently to mix the ingredient well and let stand the mixture for 5 minutes.
    5. Observe the change occurring in the mixture.

Observation: – The mixture in the test tube becomes violet.

Result: – A violet colour indicates presence of proteins in the food item.

 

Importance of the Protein:

    • Many proteins serve as building material of cell and tissues. These are essential for growth, repair and reproduction.
    • The cocoon that protects the pupa of silk moth is formed of silk fibers of the white insoluble protein.
    • Certain proteins form enzymes and hormones (insulin, parathormone) and regulate metabolism. These proteins are called functional proteins.
    • Some proteins act as antibody and defend the organism against foreign materials entering the body.

 

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