CHEMISTRY INVESTIGATORY PROJECT
COMPARISION OF GLUCOSE IN VARIOUS FRUITS
ACKNOWLEDGEMENT I would to like to express my special thanks of
gratitude to my teacher Shri. K Srinivasulu Sir as well as our
principal Shri. P.S.Raju Sir who gave me the golden opportunity to
do this wonderful project on the topic Comparision of Glucose in
various Fruits, which also helped me in doing a lot of Research and
I came to know about so many new things.I am really thankful to
them.
Secondly I would also like to thank my parents and friends who
helped me as lot in finishing this project within the limited
time.
THANKS AGAIN TO ONE AND ALL OF YOU
CERTIFICATEIt is to certify that the project entitled
Comparision of Glucose in various Fruits being submitted by Chetan
Singh of CLASS XII (Science), Kendriya Vidyalaya Gachibowli in the
academic year 2015-2016 is a bonafide piece of work carried out
with the consultation of the Supervisor.
SIGN. OF EXTERNAL SIGN. OF EXAMINER TEACHER
SIGN. OF PRINCIPAL
INDEX PAGE1. INTRODUCTION2. THEORY3. EXECUTION OF PROJECT4.
OBSERVATIONS5. CONCLUSION6. BIBLIOGRAPHY
INTRODUCTIONIn general, fresh fruits are healthy, nutritious
foods that are good sources of vitamins, minerals, phytochemicals,
and fiber. Further, they are instrumental in maintaining a net
alkaline-yielding diet. Olives, dates, figs, and grapes were some
of the first fruits to be domesticated, and pits from these fruits
initially appear in the archeological record about 6,000 years ago
in the Near East. However, the common fruits we eat today bear
little resemblance to their wild ancestors. Domesticated fruits are
almost always larger, sweeter, and contain less fiber than their
wild counterparts. Compare a Golden Delicious apple to a crab apple
and you begin to get the picture.Dr. Cordains original
recommendation to eat fresh fruits as your appetite dictates still
holds for most people. However, if you are very much overweight or
are insulin resistant, he recommends that you initially limit high
sugar fruits (grapes, bananas, mangos, sweet cherries, apples,
pineapples, pears and kiwi fruit) from your diet until your weight
starts to normalize and your health improves. Try to include more
vegetables in lieu of the high-sugar fruit. As per his previous
recommendations, dried fruits contain excessive sugar, and from the
table below, you can see they more closely resemble commercial
candy than their fresh counterparts. Note that some fruits
(avocados, lemons, and limes) are very low in total sugar and
should not be restricted.Glucose:Glucose is a very important
monosaccharide in biology. It is one of the major products of
photosynthesis. The living cell uses it as a source of energy and
metabolic intermediate. The name "Gluc" comes from the Greek word
"glykys", which means "sweet", plus the suffix "-ose" which denotes
a sugar.Two stereoisomers of the aldohexose sugars are known as
glucose, only one of which (D-glucose) is biologically active. This
form (D-glucose) is often referred to as dextrose monohydrate, or,
especially in the food industry, simply dextrose (from
dextrorotatory glucose).
Structure of Glucose:D or L Designation:For the structure of
carbohydrates the bonding pattern of the hydrogen and hydroxyl
groups around each carbon atom is very important. An asymmetric
carbon atom is that a carbon atom which is bonded to four different
groups. Glucose, with six carbon atoms, has four asymmetric carbon
atoms. The arrangement of the OH's and H's on these atoms is very
important. Structural formulas for sugar molecules are often
written in the vertical arrangement with the aldehyde or the ketone
group at or near the top. When written in this particular way, the
position of the OH on the last asymmetric carbon atom will tell us
whether we are dealing with a "D" sugar or an "L" sugar. "D" stands
for dextro and "L" stands for levo. If the OH is on the right, it
is a "D" sugar, in this case D-glucose. If the OH is on the left,
then it has been "L" sugars. When you see D's and L's in front of
the names of carbohydrates, this is the reason for it.
THEORYFehling's solution:
Use of Fehling's solution:Fehling's test can be used as a
generic test for monosaccharides. It will give a positive result
for aldose monosaccharides (due to the oxidisable aldehyde group)
but also for ketose monosaccharides, as they are converted to
aldose by the base in the reagent, and then give a positive result.
For this reason, Fehling's reagent is sometimes referred to as a
general test for monosaccharides.Fehling's can be used to screen
for glucose in urine, thus detecting diabetes. Another use is in
conversion / breakdown of starch to glucose syrup and
maltodextrins, to measure the amount of reducing sugars and
calculating the dextrose equivalent (DE) of the starch sugar.Theory
of Estimation of Glucose:A freshly prepared Fehlings solution is
first standardized by titration against a standard solution of pure
glucose A.R. The standardized Fehlings solution is then used to
determine the amount of glucose in an unknown sample or solution by
direct titration.The Fehlings solution being a solution of cupric
ions is blue in colour and at the end point changes to red colour
precipitate of cuprous oxide. As the supernatant liquid is blue and
the precipitate is red in colour, there may be some difficulty in
determination of end point accurately. Hence sometimes a
methylene-blue indicator is employed for accurate determination of
the end point.C6H12O6 + 2CuO C6H11O5.COOH + Cu2O Glucose Cupric
Oxide Gluconic Acid Cuprous oxide (Fehlings solution)
EXECUTION OF PROJECT
Materials:(1) Hydrometera. Travel-sized Eyedrops Containerb.
Nail(2)Ruler(3) 200 ml Beaker(4) Cup (170 ml at its highest
marking)(5)Universal pH Indicator Paper(6)Juicer(7)Celery
juice(8)Orange juice(9)Red watermelon juice(11)Dragonfruit
juice(12) Peach juiceProcedureThe variables for our investigation
are as follows:Independent variable: Sugar content in
fruits/BxDependent variable: pH of fruitsControlled variables:(1)
Amount of fruit juice (170 ml)(2) Environmental conditions(3) Cup
used(4) Type of Universal pH Indicator Paper(5) Hydrometer usedA.
To construct the hydrometer(1) Twist open the cap of the
travel-sized eyedrops container.(2) Squeeze the eyedrops container
to dispose of all its contents.(3) Drive a nail into the
opening.
B. To calibrate the hydrometer(4) Use the 200 ml measuring
beaker to measure 200 ml of tap water.(5) Fill the cup with 170 ml
of the water, to the highest marking.(6) Measure the height of the
water level in the cup.(7) Place the hydrometer in the water.(8)
Measure the height of the hydrometer above the water level/cm.(9)
Pour the tap water back into the 200 ml measuring beaker and add
sugar to make a sugar solution.(10) Repeat Steps 5, 7-9 for 5%
sugar solution, 10% sugar solution, 15% sugar solution and 30%
sugar solution thrice.C. To obtain the juice(11) Blend the peaches
in the juicer so as to obtain 170 ml of peach juice, to fill the
cup to the highest marking.D. To measure the sugar content of the
fruit juices(12) Place the hydrometer in the fruit juices.(13)
Measure the height of the hydrometer above the water level/cm.(14)
Compare the result of Step 13 with the pre-obtained values for each
sugar solution in Part (B) to estimate the sugar content of the
fruit juices/Bx.E. To measure the pH of the fruit juices(15)
Immerse a strip of Universal pH Indicator Paper into the fruit
juice for 1-2 seconds.(16) Shake off excess liquid.(17) Compare the
colour produced with the colour chart within 3-5 seconds by holding
it against the nearest matching colour.(18) Repeat steps 12 to 17
three times.(19) Obtain the average of the results.(20) Repeat
steps 11 to 19 for the other fruits and the control, tap water,
thrice.
OBSERVATIONS AND CALCULATIONSAnalysis of resultsTabulate the
results.Plot a graph of the sugar content and the pH of the
fruits.Analyse the graph and determine the relationship between the
sugar content and the pH of the fruits.
Results Analysis
CONCLUSIONFrom our experiment results, we were able to conclude
that generally, the higher the sugar content of the fruit juice,
the lower of the pH of the fruit juice. Celery juice which had the
lowest sugar content of 0.0 degrees Bx had the highest pH of 6.
Similarly, yellow watermelon juice which had an average sugar
content of 2.5 degrees Bx had an average pH of 5. Red watermelon
juice, dragonfruit juice, peach juice and apple juice, which all
had the highest sugar content of 10.0 degrees Bx, all had a pH of 3
to 5, comprising the lower pH readings in the experiment.However,
there was one exception to our trend present in our experiment
results, namely oranges. They had a low pH and low sugar content at
the same time.Two potential questions for future research that
arose during the experiment were, firstly, what other factors
affect the pH of fruit juice, and secondly, what factors affect the
sugar content of fruit juice.
BIBLIOGRAPHY https://hforhealthyfruits.wordpress.com/
http://www.lumcon.edu/education/studentdatabase/hydrometer.asp
http://courses.chem.indiana.edu/c121/documents/HowmuchsugarisinSoftDrinksandFruitJ
www.telegraph.co.uk News Health Health News
www.diabetesforecast.org/2014/07-jul/should-i-drink-fruit-juice.htm
