11/8/2013

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Biomolecules in Food

Investigating what we eat…

And then making a comic.

Due Date: Nov. 22, 2013

Safety & Process

�� Be careful Be careful with sharp objects used with sharp objects used in the lab.in the lab.

�� Safety goggles need to be wornSafety goggles need to be worn..

�� Prescription eyewear is adequate.Prescription eyewear is adequate.

�� Clean and return all materials.Clean and return all materials.

Food Preparation

�� Liquefy the solid food you will be Liquefy the solid food you will be testing with a mortar and pestle testing with a mortar and pestle first. Add a few first. Add a few mLmL of water if of water if necessary.necessary.

�� You may need to add some sand to You may need to add some sand to the mortar to help grind the food.the mortar to help grind the food.

�� Perform the following tests for Perform the following tests for each food item. Take LOTS of each food item. Take LOTS of pictures.pictures.

pH Test

�� Use Use pH paper to determine the pH paper to determine the acidity/alkalinity of the food.acidity/alkalinity of the food.

�� Use half a piece of pH paper per Use half a piece of pH paper per test. test.

�� Follow pH Follow pH paper instructions paper instructions ––wait the appropriate amount of wait the appropriate amount of time before making your readingtime before making your reading..

��Note that the Note that the colourcolour of the food you of the food you are testing might make the results are testing might make the results more difficult to readmore difficult to read

Iodine Test

�� Iodine Iodine reacts with starch to form a reacts with starch to form a dark dark purple/bluepurple/blue--black black colourcolour. If it . If it remains remains brown (the brown (the colourcolour of the of the iodine) iodine) it is negative for starch.it is negative for starch.

�� Add a few drops of iodine to a Add a few drops of iodine to a small sample of the food.small sample of the food.

�� Record observations.Record observations.

Benedict’s Test

�� Add ~5 Add ~5 mLmL of food slurry to of food slurry to a test tube. a test tube. Then add Then add 5 5 mLmL of Benedict’s reagent.of Benedict’s reagent.

�� Heat the test tube for five Heat the test tube for five minutes in a minutes in a hot water bath hot water bath

�� If the mixture changes If the mixture changes colourcolour (to (to greengreen, , yellowyellow, , orangeorange, , redred) then ) then the the food contains food contains simple sugars (i.e. simple sugars (i.e. monosaccharidesmonosaccharides).).

�� Note: this test does not work for Note: this test does not work for sucrose (table sugar).sucrose (table sugar).

11/8/2013

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Biuret Test

�� Add ~5 Add ~5 mLmL liquefied food to a test liquefied food to a test tube.tube.

�� Add 5 drops of Add 5 drops of BiuretBiuret solution to solution to the tube.the tube.

�� A A colourcolour change to violet indicates change to violet indicates peptide bonds peptide bonds (the bonds that (the bonds that hold amino acids together).hold amino acids together).

Smear Test

�� Place a small amount of the food Place a small amount of the food on a piece of paper towel labeled on a piece of paper towel labeled with group and food type.with group and food type.

�� When dry, hold it up to a source of When dry, hold it up to a source of light. If the paper towel is light. If the paper towel is translucent then there is fat translucent then there is fat present. Estimate from 1present. Estimate from 1--10 how 10 how much fat was in the food.much fat was in the food.

STATIONS

�� pH test pH test –– acidity/alkalinityacidity/alkalinity

�� Iodine test Iodine test –– starch contentstarch content

�� Benedict’s test Benedict’s test –– simple sugarssimple sugars

�� BiuretBiuret test test –– protein contentprotein content

�� Smear test Smear test –– lipid contentlipid content

The Report

Use your pictures to create a comic Use your pictures to create a comic that includes the following:that includes the following:

�� Materials Materials you used.you used.

�� Procedures Procedures you followed.you followed.

�� Observations you madeObservations you made..�� Discuss results for each food.Discuss results for each food.

�� Did any results surprise you?Did any results surprise you?

�� Use Comic Life Use Comic Life and and create a create a professional comic/graphic work. professional comic/graphic work.

www.plasq.com/downloads/winwww.plasq.com/downloads/win

�� Due Due Friday, Nov. 22Friday, Nov. 22ndnd

The Report, cont’d

11 -- PoorPoor 33 -- SatisfactorySatisfactory 55 -- ExcellentExcellent

PresentPresent--ationation

•• Difficult to find Difficult to find informationinformation

•• Little Little impact/aesthetic impact/aesthetic valuevalue

•• Several errors in Several errors in languagelanguage

•• Adequate layoutAdequate layout

•• Some Some

impact/aesthetic impact/aesthetic valuevalue

•• Few errors in Few errors in languagelanguage

•• Layout very userLayout very user--friendlyfriendly

•• High High impact/aesthetic impact/aesthetic valuevalue

•• No errors in No errors in languagelanguage

ContentContent

(weighted (weighted x2) x2)

•• Several missing Several missing requirementsrequirements

•• Little depth of Little depth of contentcontent

•• Incorrect scientific Incorrect scientific informationinformation

•• Requirements Requirements generally metgenerally met

•• Content coverage Content coverage acceptableacceptable

•• Scientific info Scientific info generally correctgenerally correct

•• All requirements All requirements met/exceededmet/exceeded

•• Great depth of Great depth of contentcontent

•• All scientific All scientific

information information correctcorrect