12TH Chem.

CONTENTS
 Certificate
 Acknowledgement
 Verification
 Objectives of the Project
 Introduction
 Material Required
 Procedure
 Observation
 Conclusion
 Bibliography
CERTIFICATE
This is to certify that the investigatory

Chemistry project report entitled
“To Study the digestion of starch by
salivary amylase and effect of
temperature and pH on it”
has been completed under my supervision.
VARSHA TRIPATHI TANU

SINGH
(SUBJECT TEACHER)
ACKNOWLEDGEMENT
As a student of class XII, I did this project as a
part of my studies entitled “To Study the
digestion of starch by salivary amylase and
effect of temperature and pH on it”
I owe a deep sense of gratitude to my chemistry
teacher whose valuable advice, guidance help me
in doing this project from conception to
completion.
At the same time I can't forget to express my
thankfulness to Principal of our School for
extending his generous patronage and constant
encouragement.
Finally, I am thankful to my parents for helping
me economically and my friends for giving me a
helping hand at every step of the project.
TANU SINGH
CLASS- XII ‘A’
Objectives of the Project
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
 To study digestion of starch by saliva.
 To study the effect of temperature on the

digestion of starch by saliva.
 To study the effect of pH on the salivary

digestion of starch.
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 hydrolyse the big
molecules of food into many molecules. For
example starch into mono-saccharides 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
disrupt 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.
MATERIAL REQUIRED
The requirements for experiment

of Chemistry Project Report are as
under-
 Test tubes
 Test tube stand
 One dropper
 Beaker
 Stop watch
 Starch and Iodine solution
 Thermometer
 Dil. HCl and Dil NaOH solution.
PROCEDURE
Procedure for Chemistry Experiment 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 a 100ml beaker and add
enough water to make a paste. Dilute the
paste by adding 50ml water and boil for
about 5 min.
3) Digestion of starch (a) take 5ml of the starch

solution in a test tube. Add 2 ml 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
ml 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.
OBSERVATION
Time
Passed 1 2
3 Min. 4 Min.
after Min. Min.
mixing
Colour Deep Light
Blue No Blue
Intensity Blue 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.
Procedure : Effect of temperature on the

digestion of starch by saliva.
 Take three test tubes and label these 1, 2,

3.
 Take 5ml of the starch solution, 2ml of the

saliva solution and 5 ml of water in each
test tube.
 Place test tube No. 1 in water at room

temperature, test tube No.2 in a beaker
containing water at 500 C and test tube
No.3 in boiling water.
 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.
Procedure : To study the effect of pH on the

salivary digestion of starch
1.Take three test tubes and label these 1,
2, 3.
2.Add 5ml of the starch solution, 2ml of
the saliva solution in each test tube.
3.Now add 2 ml of water inn test tube
No. 1, 2 ml of dil HCl in test tube No.
2 and 2ml of dil NaOH solution in test
tube No. 3 and shake carefully.
4.Keep the three test tubes in water at
room temperature for about 10
minutes.
5.Add two 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
saliva with increase in temp salivary analyse
get inactivated and process of digestion do not
take place.
BIBLIOGRAPHY
Internet Source :
 www.google.com
 www.yahoo.com,
 www.wiki.com,
BHARAT JYOTI VIDYALAYA
ANUPPUR (M.P.)
CBSE/AFF./1031224
SESSION: 2023- 2024

CHEMISTRY
INVESTIGATORY PROJECT
To Study the Digestion of Starch by Salivary Amylase and Effect
pH and Temperature on it
Submitted by:
Under the Guidance of:
TANU SINGH MRS.VARSHA
TRIPATHI
CLASS-XII ‘A’
Department of Science
(INTERNAL) (EXTERNAL)
(PRINCIPAL)
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CONTENTS

This is to certify that the investigatory

VARSHA TRIPATHI TANU

The main objective of this chemistry project report

 To study digestion of starch by saliva.

 To study the effect of temperature on the

 To study the effect of pH on the salivary

Every health book insists on the chewing of food.

The requirements for experiment

1) Collection of Saliva - Rinse mouth throughly

2) Preparation of starch solution - Take about

3) Digestion of starch (a) take 5ml of the starch

Absence of blue colour on addition to iodine

Procedure : Effect of temperature on the

 Take three test tubes and label these 1, 2,

 Take 5ml of the starch solution, 2ml of the

 Place test tube No. 1 in water at room

 After 5 minutes, observe the colour change

Procedure : To study the effect of pH on the

SESSION: 2023- 2024

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