Carbohydrate is a component of food that supplies energy (calories) to the body. One of the three macro nutrients (along with proteins and fats). Three broad categories of carbohydrates are sugars (also called simple carbohydrates), starches (also called complex carbohydrates), and fiber. Except for fiber and resistant starch, carbohydrates cause more and faster blood glucose rises than the other macro nutrients. Fiber and resistant starch are not digested in the small intestine, but have many positive effects.
Test for carbohydrates 1. Molisch test2 ml of the extract, add 1 ml of α-napthol solution, add concentrated sulphuric acid through the sides of the test tube. Purple or reddish violet color at the junction of the two liquids reveals the presence of carbohydrates.
2. Fehling testFehling's test differentiates between aldehydes and ketones. Aldehydes can be oxidized by Cu
2+ in the presence of a strong base to form carbonic acids. Ketones cannot be oxidized by this reaction. When the Cu
2+ oxidizes the aldehydes it is reduced to Cu
+, and forms the compound Cu
2O, which is a reddish precipitate. That is how you know you have an aldehyde.
Fehling's reagent is usually formed by mixing CuSO
4, sodium citrate, and sodium carbonate. The carbonte is used to raise the pH, but doing so would normally form Cu(OH)
2, a precipitate. That is where the sodium citrate comes it---the citrate complexes the Cu
2+ ions and prevents them from precipitating
1 ml of the extract, add equal quantities of Fehling solution A and B, upon heating formation of a brick red precipitate indicates the presence of sugars.
Fehling's Test Video In Youtube 3.Benedict’s test5 ml of Benedict’s reagent, add 1 ml of extract solution and boil for 2 minutes and cool. Formation of red precipitate shows the presence of sugars.
Benedict Test Reducing Sugars Youtube Video 
