Food Tests

Question 1

Describe how to do the test for starch and what is it called?

Answer 1

Iodine Test
Some drops of iodine to starch
Stir and record colour change
Yellow to blue-black

Question 2

Describe how to do the test for protein and what is it called?

Answer 2

Biuret test
-Add biuret solution
-Shake gently
Blue to purple

Question 3

Describe the test for reducing sugar (glucose) and non reducing sugar and what is it called?

Answer 3

The Benedict’s test
-Add Benedict’s solution and boil
Blue to orange
For non reducing add hydrochloric acid before to hydrolyse glycosidic bonds and neutrilise

Question 4

Describe test for lipids

Answer 4

-Mix in equal volumes of ethanol and water
-Shake vigorously
Change to cloudy emulsion