LAB
NUTRIENT ANALYSIS
SBI3U
INTRODUCTION
Carbohydrates (like starch and glucose), proteins and lipids (fats) are all very important organic
nutrients in our diets.
There are specific tests which identify the presence of the each of the nutrients. You will perform
these tests on control substances known to contain the nutrient so as to be able to recognize a
positive test. You will then test a food for the presence of each of the nutrients.
MATERIALS
Benedict’s solution
Butter
Brown paper
Egg whites (unboiled)
Corn syrup
Vegetable oil
Water
Carrot or potato
Iodine solution
Mortar and Pestle
Test tubes
Hot water bath
Cornstarch
Biuret reagent
Test tube holder
Food samples
Procedure
You will be writing your own procedure in the space below for each of the nutrients. You will have
to research how to test for these nutrients so be sure to put all information in your own words and
reference all material sources.
PART A: TEST FOR Glucose
PART B: TEST FOR STARCH
PART C: TEST FOR PROTEIN
PART D: TEST FOR FAT
NUTRIENT ANALYSIS
LAB
SBI3U
TABLE 1: TEST FOR FOOD NUTRIENTS
SUGAR
STARCH
FAT
PROTEIN
FAT
PROTEIN
POSITIVE TEST
NEGATIVE
TEST
TABLE 2: NUTRIENT IN FOOD SAMPLES
FOOD
SUGAR
STARCH
Discussion
1. What are the monomers that make up each type of macromolecule tested?
2. A very thin slice is removed from a peanut, crushed with a mortar and pestle then
smeared on a piece of brown paper. Then a drop of Biuret reagent is added to the
peanut slice. When you examine the peanut slice under a microscope, patches of blueviolet are visible. What conclusions can you draw from your examination?
3. A cracker crushed in water will test positive with iodine but negative with benedict’s
solution. A cracker crushed in water has another chemical called amylase added to it.
After a few minutes, this cracker tests negative with iodine and positive with
benedict’s solution. Explain what happened.