MOUNT LITERA ZEE SCHOOL
BHAGABATIPUR, BHUBANESWAR
CHEMISTRY PROJECT
SESSION: 2023-2024
A PROJECT REPORT ON
“STUDY OF DIGESTION OF STARCH BY SALIVARY
AMYLASE AND EFFECT OF PH AND TEMPERATURE ON IT”
SUBMITETED BY:
SWAYAMSHREE
CLASS – XII (SCIENCE)
ROLL NO: 12655050
Under the Guidance of
Rasmi Prakash Barik
PGT(Chemistry)
MOUNT LITERA ZEE SCHOOL, BHUBANESWAR
CERTIFICATE
This is to certify that SWAYAMSHREE, student of class XII
(Science) has successfully prepared the report on the project entitled
“study of digestion of starch by salivary amylase and effect of ph and
temperature on it” under the guidance of MR. RASMI PRAKASH
BARIK (PGT Chemistry).
This report is the result of her efforts and endeavors.
The report is found worthy of acceptance as final project report for
the subject Chemistry of class XII (science).
Signature of Internal Examiner
Signature of External Examiner
Principal’s Signature
DECLRATION
I hereby declare that the project work entitled, “study of digestion of starch
by salivary amylase and effect of ph and temperature on it” submitted to
Department of Chemisrty, Mount Litera Zee School, Bhubaneswar is prepared
by me.
Swayamshree
Class – XII (Science)
Roll No.- 12655050
ACKNOWLEDGEMENT
I would like to express a deep sense of thanks and gratitude to my project guide
Mr. Rasmi Prakash Barik for guiding me immensely through the course of theproject.
He always evinced keen interest in my project. His constructive advice and constant
motivation have been responsible for the successful completion of this project.
My sincere thank goes to Dr. Sudhansu Kumar Sahu (Principal) and Miss Mitali
Rani Chakrabarty (Vice-Principal) for his co-ordination in extending every
possible support for the completion of this project.
I must thank my classmates for their timely help and support for completion 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.
Swayamshree
Class – XII (Science)
Roll No.-12655050
INDEX
SL NO.
01.
CONTENT
PAGE NO.
1
AIM
2
02.
OBJECTIVE OF THE PROJECT
3
03.
INTRODUCTION
4
04.
APPARATUS REQUIRED
5
05.
EXPERIMENT 1
6
06.
OBSERVATION
7
07.
CONCLUSION
8
08.
EXPERIMENT 2
9
09.
OBSERVATION
10
10.
CONCLUSION
11
11.
EXPERIMENT 3
12
12.
OBSERVATION
13
13.
CONCLUSION
14
14.
PRECAUTION
15
15.
BIBLIOGRAPHY
AIM
“ TO STUDY THE DIGESTION OF STARCH BY
SALIVARY AMYLASE AND EFFECT OF PH AND
TEMPERATURE ON IT. ”
OBJECTIVE 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 PH and temperature on it.”
1.To study the 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.
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 enzymeptyalin 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 also convert into energy generating
substances. Further, enzyme 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 temperature and pH 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.
APPARATUS REQUIRED
The requirements for the experiment of chemistry project
report are as follow:
1.Test tubes
2.Test tube stand
3.One dropper
4.Beaker
5.Stop watch
6.Starch
7.Iodine solution
8.Thermometer
9.Dilute HCL solution
10.Dilute NaOH solution
EXPERIMENT 1
AIM- To study the digestion of starch by saliva
Procedure for experiment 1 is :
1.Collection of Saliva- Rinse mouth thoroughly with coldwater and
ensure that it does not contain any foodparticles. Now take about 250ml of
lukewarm water inthe mouth and keep for about three minutes so that
salivamixes up well with it. Spit this into a beaker. Filter, ifthere is any
suspended impurity clear filtrate is salivasolution and contains enzyme
ptylin.
2.Preparation of starch solution- Take about 0.5g of starchin 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 starcha.) Take 5ml of the starch solution in a test tube. Add2ml of saliva solution
into it. Mix the solution wellby shaking the tube carefully and start a step
watch.
b.) After one minute, take out two drops of the mixturesolution from the test
tube with the help of dropperand transfer it into another test tube
containingabout 1ml of 1% iodine solution. Note the colourproduced, if any.
c.)Repeat this test after one minute taking two drops of the mixture solution
and fresh 1% iodine solution continue until the test shows no blue colour.
d.)Record the time and blue colour intensity.
OBSERVATION
Time passed after
mixing
Colour Intensity
1
minute
Deep
blue
2
minute
Blue
3
minute
Light
blue
4
minute
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.
CONCLUSION
Starch gets hydrolysed by salivary amylase.
EXPERIMENT 2
AIM- To study the effect of temperature on the
digestion of starch by saliva.
Procedure for experiment 2 is :
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. And shake the test tubes carefully.
3.Place test tube number 1 in water at room temperature, test tube
number 2 in a beaker containing water at 50°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.
OBSERVATION
Time passed
Intensity of blue colour
after mixing
Test tube 1 at Test tube 2 at Test tube 3 in
saliva solution
room
50°C
boiling water
with starch
temperature
solution(in min)
5
Light blue
Blue
Deep blue
6
No blue colour
Light blue
Blue
7
-
Faint blue
Blue
8
-
No blue colour
Blue
9
10
-
-
Blue
Blue
CONCLUSION
Temperature affects the digestion of starch by
saliva.
EXPERIMENT 3
Aim:- To study the effect of pH on the salivary
digestion of starch.
Procedure for experiment 3 is :
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 as 2ml of water in test tube number1 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.
OBSERVATION
Test tube
1
2
3
Solution taken
Colour
produced(in test
tube) with 1%
iodine solution
Starch+saliva+water
Starch+saliva+dil.HCL
Starch+saliva+dil.NaOH
No blue colour
Blue colour
Blue colour
CONCLUSION
Hydrolysis of starch by the enzyme does not
takes place in the acidic or alkaline medium.
precaution
1. All apparatus should be clean and washed properly.
2. Add equal drops of iodine in all the samples while testing for
starch.
3. Temperature variation affects enzyme activity, so take the
readings at a constant temperature for all the samples.
4. Delay in sampling or the reaction time may affect the result. So,
iodine drops must be added at fixed intervals in all samples.
BIBLIOGRAPHY
1. Chemistry NCERT Class XII
2. Wikipedia
3. Comprehensive Chemistry
THANK YOU