Investigation of Action of Saliva and 3 M Hydrochloric Acid in Two Carbohydrate Solutions

577 Words Aug 18th, 2013 3 Pages
Title : Investigation of Action of Saliva and 3 M Hydrochloric Acid in Two Carbohydrate Solutions
Objective : To investigate the action of saliva and 3 hydrochloric acid in two carbohydrate solution
Table1: Observation Conclusion
Solution A Benedict’s test:
Blue coloration turned to brick red precipitate. Reducing sugar is present in the solution A. Iodine test:
The coloration remained unchanged. Starch is absent in solution A.
Solution B Benedict’s test:
The blue coloration remained unchanged. Reducing sugar is absent in solution B. Iodine test:
The coloration turn into dark blue coloration. Starch is present in solution B.

Table 2: Tube Contents
Temperature(°C) Benedict's Test-Colour
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Therefore, the solution B in test tube 1 is broken down completely by the saliva enzyme. At temperature 95°C , salivary amylase which was present in saliva content denatured .This is because high temperature would break down the bond holding the tertiary structure and destroyed the 3D structure of salivary amylase enzyme. The active sites of enzyme therefore changed and were no longer complementary to the substrate (carbohydrates). No simple sugar was produced, hence no reaction between sugar and Benedict’s solution took place caused the solution to remain blue.
The product of the experiment conducted in Table 2 is predicted to be maltose and glucose. Both maltose and glucose are carbohydrates. Glucose is a monosaccharide while maltose is disaccharide. The structure of glucose contains single simple sugar unit but the structure of maltose contain two simple sugar unit (also known as two monosaccharides or two glucose units).
Benedict’s test was used to indicate the presence of sugar. Benedict's Solution which contains the blue copper ions (II) (Cu2+), are hydrolyzed by reducing sugars into red-brown copper (I) ions (Cu+), which is insoluble in solution. As a result, red-brown precipitate is formed.
The results of Benedict's test and iodine test for solution A is positive and negative respectively, which concludes that solution A is a reducing sugar. For solution B, the results are negative and positive respectively, which concludes in solution B