1. How to detect macromolecules in food
Chemical indicators
How to detect macromolecules in food

2. What is a chemical indicator?
A substance that changes to indicate that a specific compound is in what you’re testing.
The change can be color, temperature, odor, or production of bubbles.
They are VERY specific!
Easiest to use is color usually.

3. Indicators we will use Benedict’s Solution Lugol’s Iodine
Biuret Solution
Sudan IV

4. Benedict’s Solution Used to test for monosaccharides
Normally light blue color
Mix it with your food, then heat it up
Change of color to green, yellow, orange, or red indicates monosaccharide is present
                             green orange red brown

5. Lugol’s Iodine Used to test for polysaccharide starch
Normally yellow to light brown in color
Mix with your food
Change of color to dark purple or black indicates starch is present

6. Biuret Solution Used to test for proteins Normally light blue in color
Mix with food
Change of color to purple (light to dark range) indicates presence of a protein

7. Sudan IV Used to test for lipids, specifically fats
Normally red in color
Mix with equal parts food and water
A red-stained oil layer will separate out and float on the water surface if fat is present

8. Procedure
First you need to perform the tests on control so that you know what a positive test looks like
Then test on unknown foods
Some foods will have more than one type of macromolecule