When Estes with iodine test, the colorless solution changed to dark blue color.
This show that starch is present in solution B. From the above test, we can conclude that solution B is a starch solution so we can use it to carry out the next test. Solution B , saliva and hydrochloric acid was used in the second test. The enzyme involved in this test is salivary amylase which can found in saliva. Salivary Amylase, is called fatality it’s to break down starch to sugar. Things we ate is broken down in mouth by amylase. Amylase hydrolysis starch into a reducing agar which can give Benedict test a positive result.Body temperature is the optimal temperature for the action of amylase.
Enzymes are catalysts for any reactions. They provide an alternative way of lower activation energy to speed up the reaction. When the temperature is low, the kinetic energy of substrate and enzyme is low, this take long time for both of the substance to bind together so the rate of reaction is low. When the temperature is high, the kinetic energy of the substance and enzyme is high too.
The substrate and enzyme collide more often with each other. The rate of the both substance to bind is increase too.When the temperature reach optimal, the kinetic energy and collision increase but the rate of the substrate-enzyme bind to form is decrease because the amino acid in the molecule vibrate strongly. When the temperature is too high and exceed the optimum temperature for the enzyme to react, the thermal energy will cause the enzyme to denature. The high temperature break the hydrogen bond which hold the tertiary and secondary structure of the enzyme, the enzyme lose its shape and the substrate cannot bind to the active site anymore.
HCI is to catalyst the organic propose. Starch is make up with a long chain of sugar molecules by glycoside bond. The bond can be broken through hydrolysis to release glucose. The simple sugar, glucose can be separated by HCI. Hydrochloric acid add H+ in the solution and thus hydrolysis occur.
When HCI add to solution B, it hydrolysis carbohydrate to sugar. And it give Benedict test a positive result meaning that reducing sugar is present. But the hydrolysis with HCI can only occur if the temperature is high enough for the reaction to occur.When the titer of solution B and HCI was incubate at ICC the result remain unchanged because the starch molecule not been broken down yet.
When solution B mixed with same amount of saliva, and incubate at ICC for 5 miss, it change the clear blue solution to opaque green and red precipitate is formed. This result show that a small quantity of sugar is present in the solution. The amylase in saliva hydrolysis starch in solution B to a reducing sugar. After incubate a t the same temperature the same solution of solution b and saliva for minis, the clear blue elution change to opaque green which indicate that sugar is present.This result means that a temp of 37 is suitable for amylase to hydrolysis the starch into glucose. Incubation of solution b plus HCI at ICC for miss give a negative result of Benedict test.
The blue solution remain unchanged. There is no sugar present in the solution which mean that HCI does not hydroxyl starch in solution b . After 35 miss of incubation of ICC, the blue solution remain unchanged too. The starch does not be hydrolysis by HCI. This result show that the temperature is not suitable for hydrolysis between HCI and starch.