Date: ____________________________
Name:____________________________
Partners Names:
____________________________
Lab: Testing For Nutrients in Food
PURPOSE: To determine
_________________________________________________________________________________________
__________________________________________________________________________________________________
____________________
HYPOTHESIS:
If carbohydrate is present ___________________________________ will turn _________________________________.
If a monosaccharide /disaccharide is present ________________________________ will turn ______________________________.
If proteins are present _____________________________________will turn ___________________________________.
If lipids are present ________________________________________ will turn _____________________________________.
MATERIALS: Refer to Textbook: 38-39 with modifications
Main Items: Lugol’s solution (iodine), benedict’s solution, biuret solution, paper towel, many food items, test tubes,
hot plate, water, 500 mL beakers
PROCEDURE: Refer to Textbook: 38-39
Method / Modifications to the Lab
Procedure:_____________________________________________________
__________________________________________________________________________________________
__________________
OBSERVATIONS: Results for nutrients found in certain foods.
Food Item
Carbohydrate
Simple Carb
Lugol’s soln/iodine
mono/dissaccharide
Benedict’s Solution
Proteins
Lipids draw
Lipids
circles: compare to
water on
Biuret
paper towel
Sudan IV
Glucose
Sucrose
Oil
Butter
Cracker
Potato
Bread
Albumin
Milk
Banana - unknown
Yogurt - unknown
Nut butter - unknown
Reference Table
Indicator
Nutrient Testing For
Positive Result (+)
Negative Result
Iodine
Carbohydrate
Turns black
stays red/brown
Benedict’s Solution
Sugar
Turns orange/red
green or no change
Biuret Solution
Proteins
Pink or purple
blue
Paper Towel
Fats
dries clear
dries normal
Sudan IV
Fats
Turns brick red (orange-red)
Stays dark red
DISCUSSION: pg 39 Answer quesstions g), j), k) l), n) AND the questions below...
1.
Were any of the food items positive for more than one nutrient? Why do you think this is?
2.
Were there any food items that were positive for a nutrient you did not expect? Give examples.
3.
Were there any food items that were not positive for a nutrient you thought would be there?
Give examples.
4.
a) Compare identifying types of macromolecules using indicator dropper bottles to using
diagrams showing the functional groups of each of the molecules. Which would likely be more
accurate? Give reasons for your answer.
b) In a 2-3 paragraphs explain how you would identify carbohydrates, lipids, proteins and
nucleic acids if you were given the functional groups (combination and arrangement of
elements in each solution). Refer to the group exercise we did in class.
CONCLUSION:
- Restate your purpose.
- Which macromolecules did the uncategorized food items contain and indicate the tests that told you this.