Food Tests

Question 1

Test for starch (3p)

Answer 1

• add a few drops of iodine to food sample
• gently shake to mix
• if starch is present colour change from orange to black

Question 2

Test for sugars

Answer 2

• add a drop of Benedict’s solution to a prepared food sample
• gently heat
• if positive you’ll see a colour change from blue to brick red

Question 3

Tests for protein

Answer 3

• add a few drops of the Biuret solution to a food sample
• gently shake
• if positive colour change from blue to purple/ lilac

Question 4

Test for lipids

Answer 4

• add a few drops of Sudan stain solution to food sample
• shake tube to mix
• if lipids are present a distinct layer will form as the lipids separate