P6 STARCH

OBJECTIVES 

Reveal the presence of starch in different foods and in a plant and know why it appears in any of them.

MATERIAL 

·        A piece of Frankfurt

·        A piece of jam

·        A leaf

·        A piece of a potato

·        A watch glass

·        A knife

·        Wire gauze

·        A lab burner

·        Lugol.

·        A dropper.

·        Ethanol

PROCEDURE

THE LEAF’S PROCEDURE

·        We have to heat the leaf for 2 minutes.

·        Then we take the leaf and we put it inside a test tube with ethanol.

·        We come back to heat it for 10 minutes.

·        Then we bring it out from the tube and we put it in a watch glass.

·        We add it lugol.

THE FOOD’S PROCEDURE

·        We cut a part from a potato, from Frankfurt and from jam.

·        Then we put them all in a different watch glass.

·        And we add lugol to reveal the starch presence.

RESULTS: WHE WE ADD IODINE SOLUTION TO THE FOOD SAMPLES (POTATOE, FRANKFURT SAUSAGE AND JAM), POTATOE AND FRANKFURT SAUSAGE STAIN TO DARK PURPLE OR BLACK. IT DOESN’T HAPENS WITH JAM.

CONCLUSION: IODINE SOLUTION IS AN INDICATOR OF STARCH PRESENCE. POTATOE AND FRANKFURT SAUSAGE CONTAIN STARCH.

QUESTIONS

Which is the origin of the starch that you can see in the leaf?  Photosyntesis. 
Explain the significance of boiling the leaf in water? Interrupt the photosyntesis.

Explain the significance of boiling the leaf in ethanol? Extract the clorophyll. 
Explain the significane of rinsing the leaf in water? To eliminate any remains of colorophyll.