mystery solution challenge - testing for presence of starch sugar and protein 2

8/14/2019 Mystery Solution Challenge - Testing for Presence of Starch Sugar and Protein 2

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Mystery Solution

ChallengeWhich solution contains:

GlucoseStarch

Protein?


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Mr Stuart has mixedup 5 importantfood samples (S1-

S5) and needs tofind out which iswhich

You are the fooddetectives that canuse science to help

him


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These are Mr StuartsSamples

2% Egg Albumen

20% Glucose

1% Starch 0.2% Glucose

0.1% Starch

But which is which???


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In front of you there are the 5samples

Take a small amount of one sample andplace in to 3 test tubes so they fill to1/3 full

You need to do all three tests to confirm

which solution is which

Complete the first test to decide if itcontains Starch

Then the second to test for Glucose

The third to determine Protein

presence


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Test for starch

Put a few drops of the mixture fromjar 1 in a test tube. Add a drop ofiodine to the tube.

A positive result turns dark blue


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Test for sugar(glucose)

A couple of drops of Benedicts solnis added to a third of a test tube of

the sample Place the sample into a water bath

and leave for 5 mins

Whilst waiting set up the next test

A positive result turns orange/ brick

red

i b f d


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A Biuret test can be performedin the laboratory to identify the

presence of peptide bonds The tube on the left shows a

negative result.

The tube on the right is a positivetest for protein. Note the purplecolour of the positive test.


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ResultsTest TubeSample

ContentsS1S2S3S4

S5

%2 E g g A lb u m e n

%2 0 G lu co se

%1 S ta rch

. %0 2 G lu co se

. %0 1 S ta rch


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ResultsTest TubeSample

ContentsS1 StarchS2 StarchS3 GlucoseS4 Glucose

S5 Protein

%2 E g g A lb u m e n

%2 0 G lu co se

%1 S ta rch

. %0 2 G lu co se

. %0 1 S ta rch


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http://images.google.co.uk/imgres?imgurl=
http://images.google.co.uk/imgres?imgurl=http://faculty.ntcc.edu/mhearron/BenedictsTest.jpg&imgrefurl=http://faculty.ntcc.edu/mhearron/cell_chemistry.htm&usg=__xtIoaCA4kwlVpNzQ3DeQYCRe4ms=&h=480&w=640&sz=25&hl=en&start=17&sig2=42G7AKRyK_txN29CoYbvqQ&um=1&tbnid=OAHKU806skaMLM:&tbnh=103&tbnw=137&prev=/images?q=testing+for+sugar+benedict%27s&hl=en&safe=active&sa=N&um=1&ei=uWxeS_yDMtaUlAfs74yvAghttp://images.google.co.uk/imgres?imgurl=http://faculty.ntcc.edu/mhearron/BenedictsTest.jpg&imgrefurl=http://faculty.ntcc.edu/mhearron/cell_chemistry.htm&usg=__xtIoaCA4kwlVpNzQ3DeQYCRe4ms=&h=480&w=640&sz=25&hl=en&start=17&sig2=42G7AKRyK_txN29CoYbvqQ&um=1&tbnid=OAHKU806skaMLM:&tbnh=103&tbnw=137&prev=/images?q=testing+for+sugar+benedict%27s&hl=en&safe=active&sa=N&um=1&ei=uWxeS_yDMtaUlAfs74yvAg


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To make a vit-C indicatorsolution Experiment 1-

Mix 1 tablespoon of cornstarch into enough water to make a paste.

To this paste, add exactly 250 millilitres of water and boil for fiveminutes. Allow to cool.

Add 10 drops of the starch solution to 75 millilitres of water byusing the eyedropper.

Add enough iodine to produce a dark purple-blue color. Now theindicator solution is ready.

Put 5 millilitres of indicator solution (roughly 1 teaspoon) in a 15-milliliter test tube (one for each sample)

To the test tube, use a clean eyedropper to add 10 drops of juicefrom teh fresh fruits. For solids, pulp them in a blender andstrain the juice well. Washand clean the eyedropper for each

sample. Shake well. Place all of the test tubes against a white background.

Line up the tubes from lightest to darkest purple. The lighter thesolution, the higher the level of Vitamin C content. That'sbecause Vitamin C causes the purple indicator solution to loseits color.


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Experiment 2-

Repeat the whole process ofExperiment 1.

Repeat the whole process ofExperiment 1, this time with theconcentrate juices, not the pureones.

Compare the amount of Vitamin C ofthe concentrate juices and thefresh pure ones


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Experiment 3-

Do the whole process of Experiment1, but use Kool-aid, Sunny Delight,and, C-plus instead of the fruit

juices. Compare the results from these

juices with the juices with the juices

from concentrate and the freshpure ones.


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mystery solution challenge - testing for presence of starch sugar and protein 2

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