Presence and action of salivary amylaseamylaseamylaseamylase and the effect of pHpHpHpH

Main previous concepts: Starch / Amylase / Iodine test

� Starch (or amylum) is a carbohydrate consisting of a large number of glucose

units joined together.

� Amylase is an enzyme that breaks starch down into sugar. Amylase is present in human saliva, where it begins the chemical process of digestion.

Amylase splits starch to glucose.

� The Iodine test (or lugol) is used to test for the presence of starch. Iodine solution reacts with starch producing a blue black color.

MATERIALSMATERIALSMATERIALSMATERIALS. (Drawing and name of materials)

1 2 3 4 Water Bread

water

Bread

water

saliva

Bread

water

saliva

acid

Iodine test

(adding

Lugol)

Colour

Test result

+ or - ?

Presence of

starch?

RESULTSRESULTSRESULTSRESULTS

Explain the results for each tube.

http://www.biotopics.co.uk/nutrition/amylex.html

http://www.biologyjunction.com/amylase_on_starch_lab.htm

http://www.medbio.info/Horn/Sugars4Kids/flour_and_wood.htm