What Is Carbohydrates Benedict Test

What Is Carbohydrates Benedict Test ?

Benedict test is used to determine the presence of glucose in urine. This test is named after an American chemist Stanley Rossiter Benedict. He was instrumental in developing the reagent which is used for this test.

Benedict’s reagent is used to test the presence of all monosaccharides and also reducing sugars. It includes glucose, galactose, mannose, lactose, and maltose. Benedict’s reagent is made up of sodium carbonate, sodium citrate, and copper sulfate.   

To carry out the test for the presence of monosaccharides and reducing sugars in food, the food sample is first dissolved in water. Now a small amount of the Benedict’s reagent is added. If there is no sugar present, the color of the liquid under test shall remain blue during the course of the test which may last for 4 to 10 minutes. In the presence of sugar the color changes to green, yellow, orange, red and brown. A color change confirms the presence of glucose. Sucrose does not get directly identified in this test as it is a non-reducing sugar. If dilute hydrochloric acid is added to the liquid under test and heated prior to adding the Benedict’s reagent, it is able to produce positive result for the presence of sucrose.

The presence of glucose in urine if confirmed with the Benedict’s test is an indication of diabetes. Further tests may have to be carried out to identify which sugar is present.

Benedict’s reagent is used to test for simple carbohydrates. Complex carbohydrates such as starches do not give positive result with this test unless they are broken down by heating. Table sugar is a non-reducing sugar and can not be detected in this test.  

More Articles :

What Is Carbohydrates Benedict Test