HOW TO DETERMINE SULPHUR DIOXIDE IN DRIED FRUITS

TEST FOR SULPHUR DIOXIDE IN DRIED FRUITS

AIM:
To detect presence of SO₂ preservative in food.

APPARATUS:
Test tubes, beaker.

REAGENT:
Pararosaniline hydrochloride, formaldehyde.

PRINCIPLE:
SO₂ reacts with dye and formaldehyde to form pink/magenta color.

PROCEDURE:

• Boil fruit sample in water, cool extract.

• Add 2ml dye reagent + formaldehyde.

• Observe color change.

RESULT:
Pink color indicates presence of sulphur dioxide.