Class 12 investigatory project

1. Chemistry
investigatory project
on
Study of Digestion of Starch by Salivary Amylase and Effect of pH
and Temperature on it
Submitted by : M.Sai Charan
Class:XII
Submitted to:: Mrs.Uma Sahu
((Chemistry department))

2. Department Of Chemistry
Kendriya Vidyalaya Rayagada
CERTIFICATE
This is to certify that M.Sai Charan, a student of class XII
has successfully completed the project titled “Study of
Digestion of Starch by Salivary Amylase and Effect of pH and
Temperature on it” under the guidance of Mrs.Uma Sahu(Subject
Teacher) During the academic year 2017-18 in partial fulfillment
of Chemistry practical examination conducted by Kendriya
vidyalaya, Rayagada.
Signature of External Examiner Signature of Chemistry Teacher
Signature of the Principal
Acknowledgement

3. In the accomplishment of this project successfully, many people
have best owned upon me their blessings and the heart pledged
support, this time I am utilizing to thank all the people who have
been concerned with project. Primarily I would thank god for being
able to complete this project with success. Then I would like to
thank my principal Shri.Durga Prasad Panda and Chemistry
teacher Mrs.Uma sahu, whose valuable guidance has been the
ones that helped me patch this project and make it full proof
success his suggestions and his instructions has served as the
major contributor towards the completion of the project.
Then I would like to thank my parents and friends who have
helped me with their valuable suggestions and guidance has
been helpful in various phases of the completion of the project.
M.Sai Charan
Contents

4. 1. Certificate by Teacher. . . . . . . . . . . . . . .
2. Declaration. . . . . . . . . . . . . . . . . . . . . . . .
3. Acknowledgement. .. . . . . . . . . . . . . . . . .
4. Verification. . . . . . . . . . . . . . . . . . . . . . . .
5. Objectives of the Project. . . . . . . . . . . . .
6. Introduction. . . . . . . . . . . . . . . . . . . . . . .
7. Material Required . . . . . . . . . . . . . . . . . .

5. 8. Procedure. . . . . . . . . . . . . . . . . . . . . . .
9. Observation . . . . . . . . . . . . . . . . . . . .
10. Conclusion. . . . . . . . . . . . . . . . . . . . . .
11. Bibliography. . . . . . . . . . . . . . . . . .
Objectives of the Project Report

6. 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”1) and
1.To study digestion of starch by saliva.1)
2.To study the effect of temperature on the
digestion of starch by
saliva.1)
3.To study the effect of pH on the salivary
digestion of starch.1)
Introduction
Every Health book insists on the chewing of food. The act of
chewing stimulates the excretion of saliva. Saliva mixes up

7. 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
generatingsubstances. Further, enzymes and their activity are
very sensitive to temperatureand 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.
Materials Required
The requirements for experiment of Chemistry
Project Report are as under :

8. 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.
Chemistry Experiment 1
Procedure: 0
Rinse mouth throughlywith cold
water and ensure that it it does not contain any food

9. particles. Now take about 20ml of lupewarm water in in the
mouth and gangle for about three minutes so that saliva mixes up
well with it. it.Spit this into a beaker. Filter, if there is any
suspended impurity clear filtrate is Sali saliva solution and
contains enzyme ptyalin.
Take about 0.5g of
starch in 100ml beaker a and add enough water to make a
paste. Dilute the paste by adding 50ml water and and boil
for about 5 minutes.
(a) Take 5ml of the starch solution in a test tube. Add 2ml of
saliva solution into it it. Mix the solutionswell 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 with the help of a dropperand
transfer it into anothertest tube containingabout one one 1ml
of 1% iodine solution. Note the colourproduced,if any.
(c) Repeat this test after every one minute taking two dropsof
the mixture solution and and fresh 1% iodine solution continue
until the test shows no blue colour. Record the time the time and
blue colourintensity.
Observation

10. Time Passed
after Mixing
1 Minute 2 Minute 3 Minute 4 Minute
Colour
Intensity
Deep Blue Blue Light Blue No Blue
Absence ofblue colour onaddition
to iodine solutionmeans absence of
starchinthemixture solution.That
is whole of the starch has got
digestedor hydrolysed. .
Chemistry Experiment 2
Aim: - Effect of temperature on the digestion of starch by saliva.

11. Procedure:-0
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 wat water in each test tube.
3) Place test tube Number 1 in water at room temperature,
test tube Number 2 in a 2in a beaker containing water at 500
C and test tube Number 3 in boiling boiling water.
4)After 5 minutes, observe the colour change on mixing
two drops of the mixture mixtureof every tube with one ml
of 1% iodine solution. Note the intensity of blue of blue
coloured form.
Conclusion
Starch gets hydrolysed by salivary amylase
Chemistry Experiment 3
Aim:- To study the effect of pH on the salivary digestion of starch
Procedure:-0

12. 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 t tube.
3) Now ass 2ml of water in test tube Number 1 2ml of
Dilute HCL in in in test tube Number 2 and
2ml of Dilute NaOH solution in test Nu Number 3
and shake carefully.
4) Keep the three test tubes in water at room
temperature for about 10 min minutes.
5) Add 2 drops of the solution of each test tube with
1% iodine solution and and 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.
Bibliography

13. 1. http://www.google.com
2.http://en.wikipedia.org
3. Ncert Class 12 Chemistry
4. Dinesh Chemistry
5. Comprehensive Chemistry