“CHEMISTRY
INVESTIGATOR
Aim: To Study the rate of
fermentation of fruits and
vegetables juices.
ACKNOWLEDGEMENT
I would like to express my sincere gratitude to my chemistry
mentor Mr.__________, for his vital support, guidance and
encouragement without which this project would not have
come forth.
BONAFIDE CERTIFICATE
Certified to be the bonafide work done by
Master Pushkar Singh Sani of class XII-A in the Chemistry
project during the session 2012-2013
Date _____________.
Kendriya Vidyalaya,
A.G.C.R. Colony, Delhi
Submitted for ALL INDIA SENIOR SECONDARY
EXAMINATION held in 2013 at Kendriya Vidyalaya,
A.G.C.R. Colony, Delhi.
Examiner
INDEX
S.No.
Contents
Page no.
1.
Objective
5
2.
Introductio
n
7
3.
Theory
10
4.
Experiment
12
5.
Observatio
n
15
6.
Conclusion
17
7.
Bibliograph
y
17
OBJECTIVE:
The Objective of this project is to study the rates of fermentation of the following fruit and vegetable juices:
1) Apple juice 2) Orange juice 3) Carrot juice 4) Pomegranate juice 5) Pineapple juice INTRODUCTION:
Fermentation is the process of slow decomposition of complex
organic compound into simpler ones under the influence of enzymes.
Enzymes are complex organic compounds, generally proteins. Examples of fermentation are: souring of milk or curd, bread
making, wine making and brewing.
The word Fermentation has been derived from Latin word “ferver” which means ‘boiling’. As during fermentation there is lot of frothing of the liquid due to the evolution of carbon dioxide, it gives the appearance as if it is boiling.
Sugars like glucose and sucrose when fermented in the presence of yeast cells are converted to ethyl alcohol. During fermentation of
starch, starch is first hydrolyzed to maltose by the action of enzyme diastase (the enzyme diastase is obtained from germinated barley seeds.)
Fermentation is carried out at a temperature of 35-40 °C. This is low for most kinds of fermentation, but is beneficial for cider as it leads to slower fermentation with less loss of delicate aromas. Apple based juices with cranberry also make fine ciders; and many other fruit purées or flavorings can be used, such as grape, cherry, and raspberry. The cider is ready to drink after a three month fermentation period, though more often it is matured in the vats for up to two or three years.
THEORY:
Fruits and vegetables juice, all contains carbohydrates, i.e. glucose, fructose, sucrose etc. These are fermented by the enzyme “Zymase” to ethyl alcohol.
Carbon dioxide gas is also evolved in the process.
Rate of fermentation of these juices can be compared by estimating the amount of carbon dioxide evolved in a definite time under similar conditions from equal amount of the substances.
Another method is to find out the time taken for complete
conversion of equal amount of the juices into ethanol by the process of fermentation under similar conditions. Complete conversion can be detected by treating few drops of the solution with Fehling’s
solution. Till sugar is present in the solution, it will give positive test,
i.e. red ppts., with Fehling’s solution. When all the sugar has been
converted into ethanol by fermentation, then this will not give red ppts., with Fehling’s solution.
Figure:
EXPERIMENT: Requirements: Apparatus :
Test tubes, test-tube stand, test-tube holder, tripod stand, wire gauze, beaker, pipette (2mL), conical flasks (100mL), dropper, Stopwatch.
Chemicals :
Distilled water, yeast, Pasteur’s salt, Fehling’s solution A and B, Apple juice, Orange juice, Carrot juice, Pineapple juice, Pomegranate juice.
PROCEDURE:
• Take 5-6 clean test tubes. Pipette out 2mL of Fehling’s solution in each. Keep these tubes in boiling water in a beaker or water bath.
• Take 5.0 ml of juice in a clean conical flask and dilute it with 50
ml of distilled water.
• Add 2.0 gram of Baker’s yeast and 5.0 ml of solution of Pasteur’s salts to the above conical flask.
• Shake well the contents of the flask and maintain the
temperature of the reaction mixture between 35°-40°C.
• Take out five drops of the solution with the help of a dropper
after five minutes and add to one of the test tube containing Fehling’s solution. Note color change, if any.
• Continue this testing with 5 drops of the reaction mixture after
every 5 minutes until the test shows that no more is sugar is left in the reaction mixture, i.e. fermentation is complete.
• Note the time taken for completion of fermentation.
OBSERVATIONS:
NOTE: All the volumes of juices taken and volume of chemicals added is equal for all the juices.
Volume of fruit juice taken = _______mL
Volume of distilled water added = _______ mL
Weight of Baker’s yeast added = _______ g
Volume of solution of Pasteur’s salts = _______ mL
Normal color of all the diluted juices mixtures before starting the experimental procedure.
JUICE COLOR Apple juice Orange juice Carrot juice Pomegranate juice Observation Table: Time (in minutes)
Is any color shown on reacting with Fehling’s solution by Apple
Conclusion: ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ Precautions:
• Use equal volumes of the juices.
• Ferment the juices under identical conditions.
• Fermentation should be done at 35-40 °C temperature only.
• Warm the test tube for 2-3 minutes on water bath before inferring with Fehling’s solution.
Bibliography:
• APC Laboratory Manual Chemistry Class XII • Googleimages
• Googlesearch
• Subject teacher • Classmates
