Analysis of the results on page 19: At time initial (o min) the iodine test performed on the contents of test tube A and test tube B gave a dark blue color indicating the presence of starch in the two test tubes while the Fehling test gave a blue color in both test tubes indicating the absence of a reducing sugar. The same tests were performed at the end of the experiment at time = 15 min; the iodine test gave a brown orange color in test tube A indicating the absence of starch and a dark blue color in test tube B indicating that starch is still present. As for the Fehling test it gave a red brick precipitate in test tube A indicating the presence of a reducing sugar and a blue color inn test tube B indicating the absence of a reducing sugar.
Interpretation of the results: in test tube A, starch was hydrolyzed by salivary amylase into the reducing sugar (maltose) thus giving at the end of the experiment a negative identification test with iodine reagent and a positive identification test with the Fehling reagent. In test tube B no hydrolysis occurred since the is no enzyme.
Conclusion: Salivary amylase hydrolyses cooked starch into maltose.
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