the chemistry of food

• carbohydrates -they provide us with the fuel that makes all of the others reaction of life possible. Complex carbohydrates such as starch and cellulose are mad up of long chains of simple sugar units bonded together.
• proteins are made up of amino acids
• lipids-They are fats and oils.they are the most efficient energy store in your body and an important source of energy in your diet.

  -all lipids are insoluble in water.

  -lipids are made up of three molecules of fatty acids joined to a molecule of glycerol.
• proteins 


  -proteins are used for building up the cells and tissues of your body,as well as the basis of all your enzymes.

  -a protein molecule is made up of long chains of small units called amino acids
• carbohydrate food test

  Iodine test for starch-yellow-red iodine solution turns blue-black if the starch is present. Benedict's test for sugars-blue benedict's solution turns brick red on heating if a sugar such as glucose is present.
• proteinsfood test

  biuret test-blue biuret reagent turns purple if the protein is present
• lipids food test

  ethanol test-ethanol added to the solution gives a cloudy white layer if a lipid is present. Ethanol is highly flammable and harmful