Question

Answer the following in brief :- write test for detecting the presence of starch .​

Answer 1

Answer:

To test leaves for the presence of starch,the leaf is boiled in water and then the boiled leaf is placed in a boiling tube containing 90% ethanol (ethyl alcohol). The ethanol boils and the green colouring (chlorophyll) is removed from the leaf. The iodine reagent is then added, which causes the green areas on the leaf, where starch is supposedly present, to turn to a blue-black colour. This indicates the presence of starch in the leaf. here is the answer.

Answer 2

Material Required

Potato extract

Iodine solution

Test tube

Dropper

procedure

Take a piece of the food item. Put 2-3 drops of dilute iodine solution on it. If the colour of the food item becomes blue-black, then it indicates the presence of starch in the food item.

conclusion

(i) Food + Iodine - Blue-black colour (starch present)

(ii) Food + Iodine - No blue-black colour (no starch present)