The document is an investigatory project report by Pratyush Mohapatra, class XII science, under the guidance of Mr. M. Mohapatra, focusing on the digestion of starch by salivary amylase and the effects of temperature and pH. It outlines the objectives, procedures, observations, and conclusions of the experiments conducted. The project demonstrates how salivary amylase hydrolyzes starch in the presence of saliva, and is influenced by temperature and pH levels.

1. INVESTIGATORY PROJECT WORK
Submitted By
PRATYUSH MOHAPATRA
Class: XII Science
Under the Guidance of
Mr. M.MOHAPATRA
PGT (Chemistry)
Department of Chemistry
Kendriya Vidyalaya Khurda Road

2. Department of Chemistry
Kendriya Vidyalaya Khurda Road
C E R T I F I C A T E
This is to certify that Pratyush Mohapatra of Class XII
Science has prepared the investigatory chemistry project
entitled “To Study the digestion of starch by salivary amylase
and effect of temperature and pH on it”. The report is the
result of his efforts & endeavors.
The report is found worthy of acceptance as final project
report for the subject Chemistry of Class XII. He has prepared
the report under my guidance.
(Mr.M.Mohapatra)
PGT (Chemistry)
Department of Chemistry
Kendriya Vidyalaya Khurda Road

3. Department of Chemistry
Kendriya Vidyalaya Khurda Road
C E R T I F I C A T E
The investigatory project entitled
“To Study the digestion of starch by salivary amylase and
effect of temperature and pH on it”
Submitted by Pratyush Mohapatra ofClass XII Science
for the C.B.S.E Senior Secondary Examination class XII of
Chemistry Practical at Kendriya Vidyalaya Khurda Road
has been examined.
SIGNATURE OF EXAMINER

4. D E C L A R A T I O N
I hereby declare that the project work entitled
“To Study the digestion of starch by salivary
amylase and effect of temperature and pH on
it”, submitted toDepartment of Chemistry,
Kendriya Vidyalaya Khurda Road is prepared
by me.
PRATYUSH MOHAPATRA
Class XII Science

5. A C K N O W L E D G E M E N T
I would like to express a deep sense of thanks & gratitude to my
project guide Mrs. M.Mohapatra Mam for guiding me immensely
through the course of the project. He always evinced keen interest in my
work. His constructive advice & constant motivation have been
responsible for the successful completion of this project.
My sincere thanks go to Shri D.P SHARMA, Our principal sir, for
his co-ordination in extending every possible support for the completion
of this project.
I also thanks to my parents for their motivation & support. I must
thanks to my classmates for their timely help & support for compilation
of this project.
Last but not the least; I would like to thank all those who had
Helped directly or indirectly towards the completion of this project.
PRATYUSH MOHAPATRA
Class: XII Science
ra

6. CONTENTS
1. Certificate by Teacher. . . . . . . . . . . . . . .
2. Certificate by Examiner. . . . . . . . . . . . . .
3. Declaration. . . . . . . . . . . . . . . . . . . . . . . .
4. Acknowledgement. .. . . . . . . . . . . . . . . . .
5. Verification. . . . . . . . . . . . . . . . . . . . . . . .
6. Objectives of the Project. . . . . . . . . . . . .
7. Introduction. . . . . . . . . . . . . . . . . . . . . . .
8. Material Required . . . . . . . . . . . . . . . . . .
9. Procedure. . . . . . . . . . . . . . . . . . . . . . . . .
10. Observation . . . . . . . . . . . . . . . . . . . . . . .
11. CONCLUSION. . . . . . . . . . . . . . . . . . . . . .
12. BIBLIOGRAPHY. . . . . . . . . . . . . . . . . . . . .

7. Objectives of the Project Report
The main objective of this chemistry project
report is “To Study the digestion of starch by
salivary amylase and effect of temperature
and pH on it”and
1)To study digestion of starch by saliva.
2)To study the effect of temperature on the digestion of
starch by saliva.
3)To study the effect of pH on the salivary digestion of
starch.

8. Introduction
Every Health book insists on the chewing of food. The
act of chewing stimulates the excretion of saliva. Saliva
mixes up with the food and helps its digestion. That is,
the enzyme ptyalin or amylase present in human saliva
hydrolyzes the big molecules of food into many
molecules. For example starch into mono-saccnaricies
maltose and glucose; proteins into amino acids and fats
into fatty acids and glycerol. Thus saliva not only helps
in digestion of food but convert it into energy
generating substances. Further, enzymes and their
activity are very sensitive to temperature and ph. Even
a slight variation in these two factors, can disturb the
action of enzymes. In other words, digestion of food by
salivary amylase is also effected by pH and temperature
and can be verified experimentally. For example,
hydrolysis of starch can be verified by testing it with
iodine solution. Starch forms blue coloured complex
with iodine. If no starch is present in a system it will not
give blue colour with iodine.

9. Material Required
The requirements for experiment of Chemistry
Project Report are as under:
1) Test tubes
2) Test tube stand
3) One dropper
4) Beaker
5) Stop watch
6) Starch and Iodine solution
7) Thermometer
8) Dilute HCL and Dilute NaOH solution.

10. Chemistry Experiment 1
Procedure
Procedure for Chemistry Experiment 1 is:
1) Collection of Saliva– Rinse mouth throughly with cold
water and ensure that it does not contain any food
particles. Now take about 20ml of lupe warm water in
the mouth and gangle for about three minutes so that
saliva mixes up well with it. Spit this into a beaker.
Filter, if there is any suspended impurity clear filtrate is
saliva solution and contains enzyme ptyalin.
2) Preparation of starch solution – Take about 0.5g of
starch in 100ml beaker and add enough water to make a
paste. Dilute the paste by adding 50ml water and boil for
about 5 minutes.
3) Digestion of starch :-
(a)Take 5ml of the starch solution in a test tube. Add 2ml
of saliva solution into it. Mix the solutions well by
shaking the tube carefully and start a step watch.
(b) After one minute take out two drops of the mixture
solution from the test tube with the help of a dropper
and transfer it into another test tube containing about
one 1ml of 1% iodine solution. Note the colour
produced, if any.
(c)Repeat this test after every one minute taking two
drops of the mixture solution and fresh 1% iodine
solution continue until the test shows no blue colour.
Record the time and blue colour intensity.

11. Observation
Time Passed
after Mixing
1
Minute
2
Minute
3
Minute
4
Minute
Colour
Intensity
Deep
Blue
Blue Light
Blue
No Blue
Absence of blue colour on addition to iodine solution
means absence of starch in the mixture solution. That is
whole of the starch has got digested or hydrolysed.

12. Chemistry Experiment 2
Procedure: - Effect of temperature on the digestion of starch
by saliva.
1) Take three test tubes and label these 1, 2, and 3.
2) Take 5ml of the starch solution, 2ml of the saliva solution
and 5ml of water in each test tube.
3) Place test tube Number 1 in water at room temperature, test
tube Number 2 in a beaker containing water at 500
C and
test tube Number 3 in boiling water.
4) After 5 minutes, observe the colour change on mixing two
drops of the mixture of every tube with one ml of 1%
iodine solution. Note the intensity of blue coloured form.
Conclusion
Starch get hydrolysed by saliva amylase.

13. Chemistry Experiment 3
Procedure: - To study the effect of pH on the salivary
digestion of starch
1) Take three test tubes and label these 1, 2, and 3.
2) Add 5ml of the starch solution, 2ml of the saliva
solution in each test tube.
3) Now ass 2ml of water in test tube Number 1 2ml of
Dilute HCL in test tube Number 2 and 2ml of Dilute
NaOH solution in test tube Number 3 and shake
carefully.
4) Keep the three test tubes in water at room temperature
for about 10 minutes.
5) Add 2 drops of the solution of each test tube with 1%
iodine solution and observe the colour change
Conclusion
Temperature effects the digestion of starch by salivary
with increase in temperature salivary amylase get
inactivated and process of digestion do not take place.

14. BIBLIOGRAPHY
1 http://www.google.com/
2 http://en.wikipedia.org
3 N.C.E.R.T Class 12 Chemistry
4 Dinesh Chemistry
5 Comprehensive Chemistry