To study carbohydrates in pure form of detect its presence in food

Aim: To study carbohydrates in pure form of detect its presence in food. 

Material required: Test-tube, test-tube stand, test tube holder, burner etc.

Theory: Carbohydrates are Polyhydroxy aldehydes or polyhydroxy ketones, their derivatives and the substance which yield them on hydrolysis carbohydrates are classified as sugars and non-sugars. Sugars like glucose, fructose and cane sugar are crystalline.

Among sugars, glucose, fructose, and lactose are reducing while sucrose is non reducing sugar.

 

S.N.	EXPERIMENT	OBSERVATION	INFERENCE
1.	Conc. H2SO4 test: Sample + Conc. H2SO4 + Heat	Charring with burnt sugar smell.	Carbohydrates present.
2.	Fehling solution test: Sample solution + 1 ml of Fehling A + 1 ml of Fehling B + D	Red ppt	Reducing sugar is present
3.	Tollen’s reagent: Aq. Solution of sample + 2 ml of Tollens reagent + D	Silver mirror is formed along the surface of test tube.	Reducing sugar is present
4.	Benedict’s Solution test: Aq solution of sample + Benedict’s reagent + Heat	Red ppt	Reducing sugar is present
5.	Iodine test: Sample Solution + few drops of iodine solution	Violet colour	Starch is present

 

Result : Carbohydrates is present in given sample of food.