Food Tests

Question 1

Testing For Protein

Answer 1

Add biurets solution (yellow/brown) and look for a colour change. In the presence of starch, iodine turns a purple colour.

Different colours indicate different amounts of protein (rather than just presence / absence) so it is semi-quantitative.

Question 2

Iodine- test for starch

Answer 2

Add iodine solution (yellow/brown) and look for a colour change. In the presence of starch, iodine turns a blue/black colour.