Test for Reducing sugars and non reducing sugars and test for starch

Reduction is a chemical reaction involving the gaining of electrons. A reducing sugar therefore can donate electrons to another chemical, in this case benedicts reagent.

• Add food sample you want to test in a liquified form into a test tube
• add an equal volume of Benedicts reagent
• heat the mixture
• if solution is orange/brown reducing sugar is present.

• put sample of food in liquid form into a test tube
• add benedicts reagent
• heat test tube
• if solution remains blue reducing sugar IS NOT present
• add another sample of the food into a new test tube
• and add acid ( hydrochloric acid) as it will hydrolyse any disaccharide present
• heat
• then add an alkaline ( hydrogencarbonate solution) to nuetralise acid( benedicts reagent doesnt work under acidic conditions)
• retest the solution by heating with benedicts reagent
• if non reducing sugar is presnt solution will turn orange/brown due to reducing sugars that were produced from the hydrolysis for the non reducing sugar.

• place sample being tested in a test tube
• add two drops of iodine solution and shake or stir
• presence of starch is indicated by blue black colouration.