Food Dyes

The dyes approved for use in foods, drugs and cosmetics are called FD & C Dyes. There are 7 commonly used dyes. Of these, Blue 1 and Red 40 are the most common blue and red dyes, while Green 3 and Blue 2 are rarely used. All of the dyes have relatively complex structures. Look at several (by clicking on the name) before reading further. (Confused by the big structures?)

Blue 1 (Brilliant Blue FCF)	Blue 2 (Indigotine)	Red 3 (Erythrosine)
Red 40	Yellow 5 (Tartrazine)	Green 3 (Fast Green FCF)
	Yellow 6 (Sunset Yellow FCF)

You probably noticed that the dyes all have lots of double bonds next to each other. The nearness of these double bonds is what makes them so highly colored. You should have also noticed that all of the dyes contain some -CO₂ or -SO₃ groups. These groups contribute to the polarity of the molecule.

This completes the background. Proceed to the prelab.

introduction

background

prelab

experiment

postlab