BAL MANDIR SR.

SEC. SCHOOL

AN INVESTIGATORY PROJECT ON:

RATE OF FERMENTATION OF VARIOUS
FOOD MATERIALS

NAME :- SHISHIR
CLASS :- XIIA
SUBJECT :- CHEMISTRY
ROLL.NO :-
INDEX
 AIM
 CERTIFICATE
 ACKNOWLEDGEMENT
 OBJECTIVE
 INTRODUCTION
 THEORY
 MATERIALS REQUIRED
 PROCEDURE
 OBSERVATIONS
 BIBLIOGRAPHY
 AIM

To Compare The Rate Of

Fermentation Of Given Sample
Of Wheat Flour, Gram Flour,
Rice Flour And Potato Using
Yeast.
CERTIFICATE

This is to certify that Shishir of class-XIIA has successfully

completed the investigatory project on the topic
“TO STUDY THE RATE OF FERMENTATION IN VARIOUS FOOD
MATERALS” under the guidance of Mrs. Rani Jha (Chemistry
Teacher) during the year 2024-2025 in the partial fulfillment
of the Chemistry practical examination conducted
by CBSE.

Principal’s Signature External’s Signature Internal’s Signature

ACKNOWLEDGEMENT
I wish to express my deep gratitude and sincere thanks
principal madam for her encouragement and for all the
facilities that he provided for this project work. I extend my
hearty thanks to Ms. Rani jha, Chemistry Teacher, who guided
me to do this project and successful completion of this
project.
I take this opportunity to express my deep sense of gratitude
for her invaluable guidance, constant encouragement,
constructive comments, sympathetic attitude and immense
motivation which has sustained my effort at all stages of this
project work.

Shishir Chandra pathak

OBJECTIVE

The purpose of the experiment is - to compare the rate of

fermentation of the given samples of wheat flour, gram flour,
rice flour and potatoes.
I became interested in this idea when i saw some
experiments on fermentation and wanted to find out some
scientific facts about fermentation. The primary benefit of
fermentation is the conversion of sugars and other
carbohydrates e.g., converting juice into wine, grains into
beer, carbohydrates into carbon dioxide to leaven bread, and
sugars in vegetables into preservative organic acids.
INTRODUCTION
Fermentation typically is the conversion of carbohydrates to
alcohols and carbon dioxide or organic acids using yeasts,
bacteria, or a combination thereof, under anaerobic
conditions. A more restricted definition of fermentation is the
chemical conversion of sugars into ethanol. The science of
fermentation is known as zymology. Fermentation usually
implies that the action of microorganisms is desirable, and
the process is used to produce alcoholic beverages such as
wine, beer, and cider. Fermentation is also employed in
preservation techniques to create lactic acid in sour foods
such as sauerkraut, dry sausages, kimchi and yoghurt, or
vinegar for use in pickling foods.
HISTORY
Since fruits ferment naturally, fermentation precedes human
history. Since ancient times, however, humans have been
controlling the fermentation process. The earliest evidence of
winemaking dates from eight thousand
 Years ago in Georgia, in the
Caucasus area. Seven thousand
years ago jars containing the
remains of wine have been
excavated in the Zagros Mountains in
Iran, which are now on display at the
University of Pennsylvania. There is
strong evidence that people were
fermenting beverages in Babylon circa 5000 BC, ancient
Egypt circa 3150 BC, pre-Hispanic Mexico circa 2000 BC, and
Sudan circa 1500 BC.
There is also evidence of leavened bread in ancient Egypt
circa1500 BC and of milk fermentation in Babylon circa 3000
BC. French chemist Louis Pasteur was the first known
zymologist, when in 1854 he connected yeast to fermentation.
Pasteur originally defined fermentation as " respiration
without air ".

CONTRIBUTION TO BIOCHEMISTRY

When studying the fermentation of sugar to alcohol by

yeast, Louis Pasteur concluded that the fermentation was
catalyzed by a vital force, called "ferments" within the
yeast cells. The "ferments “ were thought to function only
within living organisms. Alcoholic fermentation is an act
correlated with the life and organization of the yeast cells,
not with the death or putrefaction of the cells, "he wrote.
Nevertheless, it was known that yeast extracts ferment
sugar even in the absence
of living yeast cells. While
studying this process in
1897, Eduard Buchner of
Humboldt University of
Berlin, Germany, found that
sugar was fermented even
when there were no yeast
cells in the mixture, by a
yeast secretion that he termed zymase.
In 1907 he received the Nobel Prize in Chemistry for his
research and discovery of "cell -free fermentation”. One
year prior, in 1906, ethanol fermentation studies led to the
early discovery of NAD+.

Eduard
Buchner

USES OF FERMENTED FOODS

Food fermentation has been said to serve five main
purposes:
# Enrichment of the diet through development of a
diversity of flavors, aromas, and textures in food
substrates .

# Preservation of substantial amounts of food through

lactic acid, alcohol, acetic acid and alkaline fermentations.

# Biological enrichment of food substrates with protein,

essential amino acids, essential fatty acids, and vitamins

# Elimination of antinutrients.

# A decrease in cooking times and fuel requirements.

# Boost the number of beneficial bacteria or probiotics in

the gut.

RISKS OF CONSUMING FERMENTED FOODS

 Food that is improperly fermented has a notable risk of
exposing the eater to botulism. Alaska has witnessed a
steady increase of cases of botulism since 1985. Despite
its small population, it has more cases of botulism than any
other state in the United States of America. This is caused
by the traditional Eskimo practice of allowing animal
products such as whole fish, fish heads, walrus, sea lion
and whale flippers, beaver tails, seal oil, birds, etc., to
ferment for an extended period of time before being
consumed. The risk is exacerbated when a plastic
container is used for this purpose instead of the old-
fashioned method, grass-lined hole, as the botulinum
bacteria thrive in the anaerobic conditions created by the
air-tight enclosure in plastic.

SAFETY OF FERMENTED FOODS

Fermented foods generally have a very good safety record
even in the developing world where the foods are
manufactured by people without training in microbiology or
chemistry in unhygienic, contaminated environments. They
are consumed by hundreds of millions of people every day
in both the developed and the developing world. And they
have an excellent safety record. While fermented foods are
themselves generally safe, it should denoted that
fermented foods by themselves do not solve the problems
of contaminated drinking water, environments heavily
contaminated with human waste, improper personal
hygiene in food handlers, flies carrying disease organisms,
unfermented foods carrying food poisoning or human
pathogens and unfermented foods, even when cooked if
handled or stored improperly. Also improperly fermented
foods can be unsafe. However, application of the principles
that lead to the safety of fermented foods could lead to an
improvement in the overall quality and the nutritional value
of the food supply, reduction of nutritional diseases and
greater resistance to intestinal and other diseases in
infants.
THEORY
Wheat flour, gram flour, rice flour and potatoes contains
starch as the major constituent. Starch present in these
food materials is first brought into solution. In the
presence of enzyme diastase, starch undergo fermentation
to give maltose. Starch gives blue-violet colour with iodine
whereas product of fermentation starch do not give any
characteristic colour. When the fermentation is complete
the reaction mixture stops giving blue-violet colour with
iodine solution. By comparing the time required for
completion of fermentation of equal amounts of different
substances containing starch the rates of fermentation
can be compared. The enzyme diastase is obtained by
germination of moist barley seeds in dark at 15 degree
celsius. When the germination is complete the temperature
is raised to 60 degree celsius to stop further growth. The
seeds are crushed into water and filtered. The filtrate
contains enzyme diastase and is called malt extract.
MATERIALS REQUIRED

i. Conical Flask
ii. Test Tube
iii. Filter Paper
iv. Water Bath
v. 1 % Iodine Solution
vi. Yeast
vii. Wheat Flour
viii. Rice Flour
ix. Potato
x. Aqueous NaCl Solution
PROCEDURE
# Take 5 grams of wheat flour in 100 ml conical flask andadd
30 ml of distilled water.
# Boil the contents of the flask for about 5 minutes. Filter the
above contents after cooling, the filtrate obtained is wheat
flour extract.
# To the wheat flour extract taken in a conical flask, add 5 ml
of 1% aq. NaCl solution.
# Keep this flask in a water bath maintained at a temperature
of 50-60 degree celsius. Add 2 ml of malt extract.
# After 2 minutes take 2 drops of the reaction mixture and
add to diluted iodine solution.
# Repeat step 6 after every 2 minutes. When no bluish colour
is produced the fermentation is complete.
# Record the total time taken for completion of fermentation.
# Repeat the experiment with gram flour extract, rice flour
extract, potato extract and record the observations.
OBSERVATIONS

Time required for the fermentation---

# Wheat flour : 10 hours

# Gram flour : 12.5 hours
# Rice flour : 15 hours
# Potato : 13 hours

CONCLUSION

Rice flour takes maximum time for fermentation and wheat

flour takes the minimum fermentation.
BIBLIOGRAPHY
# Wikipedia-the free enclyclopedia
# Chemistry manual
# Website : www.icbse.com
# Pinterest.com