Fermentation

ACKNOWLEDGEMENT:
I would like to thank my teacher Mrs. Prabeena for

guiding me through this project and for their valuable
inputs which provided me with a constant nudge for
improvement.
It is imperative to thank our Principal, Mr. Suraj Raghu
for providing me the opportunity to work on this project.
It goes without saying that my classmates for their help
in due course of this project. My parents have also
played a part in helping me in this project. My thanks
goes out to them also.
This project and reading-up on the same has provided
me with an in depth understanding of the topic. It has
nurtured my scientific temperament and curiosity.
Signature of the Candidate

BONAFIDE CERTIFICATE
Certified to be the bonafide work done by L. Sandeep
Samuel of class XII during the year 2019-2020.
Date:
THE RAJAS INTERNATIONAL SCHOOL,
Submitted for
Examiner DATE
INDEX:
S.No. CONTENTS
1. Objective
2. Introduction
3. Theory
4. Experiment 1
5. Experiment 2
6. Observation
7. Result
8. Bibliography
OBJECTIVE:
The Objective of this project is to study the rates of
fermentation of the following fruit or vegetable juices.
i) Apple juice
ii) Carrot juice
INTRODUCTION:
Fermentation is typically the conversion of carbohydrates
to alcohols and carbon dioxide or organic acids using
yeasts, bacteria, or a combination there of under
anaerobic conditions by the action of enzymes. Enzymes
are complex organic compounds generally proteins. They
are highly specific with regard to their substrates.
Fermentation in simple terms is the chemical
conversion of sugars into ethanol. Ethanol fermentation,
also referred to as alcoholic fermentation is the
biological process in which sugars such as glucose,
fructose, and sucrose are converted into cellular energy
and thereby produce ethanol and carbon dioxide as
metabolic waste products .Ethanol fermentation occurs
in the production of alcoholic beverages and ethanol fuel
and in the leavening of bread dough. Fermentation is
used in preservation techniques and in production of
foods such as yogurt, cottagecheese dhokla, idli,
chocolates, cheese etc. ‘Fermentation’ has been derived
from the Latin word ferver, which means ‘to
boil’, as during fermentation, there is a lot of
frothing in the liquid due to evolution of carbon dioxide.
This gives it the appearance as if it is boiling! Yeasts
are unicellular eukaryotic microorganisms classified in
the kingdom Fungi, Yeast size can vary greatly
depending on the species, typically measuring 3-4
μm in diameter, although some yeasts can reach over 40
μm. Most yeasts reproduce asexually by mitosis,
and many do so by an asymmetric division process
called budding. Yeasts do not form a single taxonomic
or phylogenetic grouping. The term yeast is often
taken as a synonym for Saccharomyces cerevisiae.
USES OF FERMENTATION:
 Enrichment of the diet through development of a
diversity of flavors, aromas, and textures in food
substrates.
 Preservation of substantial amounts of foods
through lactic acid,alcohol, acetic acid, and
alkaline fermentations
 Biological enrichment of food substrates with
protein, essential aminoacids, essential fatty acids,
and vitamins.
 Elimination of antinutrients.
THEORY:
Fermentation is the slow decomposition of complex
organic compounds into simpler compounds by the
action of enzymes. Enzymes are biological molecules
that catalyze chemical reactions. Fruit and vegetable
juices contain sugar such as sucrose, glucose and
fructose.
Louis Pasteur in 1860 demonstrated that fermentation is
a purely physiological process carried out by living micro-
organism like yeast. This view was abandoned in 1897
when Buchner demonstrated that yeast extract could
bring about alcoholic fermentation in the absence of any
yeast cells. He proposed that fermenting activity of yeast
is due to active catalysts of biochemical origin. These
biochemical catalysts are called enzymes. Enzymes are
highly specific. A given enzyme acts on a specific
compound or a closely related group of compounds. The
fruit and vegetable juices contain sugar such as sucrose,
glucose and fructose. These sugars on fermentation in
the presence of the enzymes invertase and zymase give
with the evolution of carbon dioxide. Maltose is
converted to glucose by enzyme maltose. Glucose is
converted to ethanol by another enzyme zymase.
Invertase:
C12H22O11 + H2O → C6H12O6 + C6H12O6
Sucrose Glucose Fructose
Zymase:
C6H12O6 + C6H12O6 → 2C2H5OH + 2CO2 ⁭
Glucose Fructose Ethanol
Diastase
2(C6H1005)n + nH20 → nC12H22O11
Starch Maltose
Maltase
C12H22O11 + H2O → 2C6H12O6
Maltose Glucose
Zymase:
C6H12O6 → 2C2H5OH + 2CO2 ⁭
Glucose Ethyl alcohol
Glucose is a reducing sugar and gives red coloured
precipitates with Fehling’s solution, when warmed.
When the fermentation is complete, the reaction mixture
stops giving any red colour or precipitate with Fehling
solution.
GENERAL REQUIREMENTS:
 Pasteur’s salts
 Yeast
 Fehling’s reagent
 Conical flasks
 Test tubes
 Beaker
 Bunsen burner, tripod stand and watch glass
FERMENTATION OF APPLE JUICE:
EXPERIMENT-1
REQUIREMENTS:
Conical flasks (250 ml), test tubes and water bath, Apple
juice and Fehling’s solution.
PROCEDURE:
1. Take 5.0 ml of apple juice in a clean 250 ml conical
flask and dilute it with 50 ml of distilled water.
2. Add 2.0 gram of Baker’s yeast and 5.0 ml of solution
of Pasteur’s salts to the above conical flask.
3. Shake well the contents of the flask and maintain the
temperature of the reaction mixture between 35-40°C.
4. After 10minutes take 5 drops of the reaction mixture
from the flask and add to a test tube containing 2 ml of
Fehling reagent. Place the test tube in the boiling water
bath for about 2 minutes and note the colour.
5. Repeat the step 4 after every 10 minutes when the
reaction mixture stops giving any red colour or
precipitate.
6. Note the time taken for completion of fermentation.
FERMENTATION OF CARROT JUICE:
EXPERIMENT-2
REQUIREMENTS:
Conical flasks (250 ml), test tubes and water bath, Carrot
juice and Fehling’s solution.
PROCEDURE:
1. Take 5.0 ml of carrot juice in a clean 250 ml conical
flask and dilute it with 50 ml of distilled water.
2. Add 2.0 gram of Baker’s yeast and 5.0 ml of solution
of Pasteur’s salts to the above conical flask.
3. Shake well the contents of the flask and maintain the
temperature of the reaction mixture between 35-40°C.
4. After 10minutes take 5 drops of the reaction mixture
from the flask and add to a test tube containing 2 ml of
Fehling reagent. Place the test tube in the boiling water
bath for about 2 minutes and note the colour.
5. Repeat the step 4 after every 10 minutes when the
reaction mixture stops giving any red colour or
precipitate.
6. Note the time taken for completion of fermentation.
PASTEUR’S SALT SOLUTION:
Pasteur salt solution is prepared by dissolving
ammonium tartrate 10.0g; potassium phosphate 2.0 g;
calcium phosphate 0.2g, and magnesium sulphate 0.2 g
dissolved in 860ml of water.
OBSERVATION:
Volume of fruit juice taken = 5.0 ml
Volume of distilled water added = 50.0 ml
Weight of Baker’s yeast added = 2.0 g
Volume of solution of Pasteur’s salts = 5.0 ml
Time (in minutes) Colour of mixture in Colour of mixture in
experiment 1 experiment 2
RESULTS:
The rate of fermentation of apple juice is than the rate
of fermentation of carrot juice.

Fermentation

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ACKNOWLEDGEMENT:

I would like to thank my teacher Mrs. Prabeena for

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