Food Tests Flashcards
What is the test for starch?
Add a drop of iodine to starch on a spotting tile
What is a positive result for starch?
Blue black colour is formed
- a coloured polyiodine complex is formed with starch
What is the test for reducing sugar? (Glucose)
Benedict’s solution + water bath
What is the positive result for reducing/non-reducing sugars?
A brick-red precipate is formed
What is the test for non-reducing sugars? (Sucrose)
Add hydrochloric acid, shake and place in water bath.
Add sodium hydroxide which will neutralise acid.
Then add benedict’s solution and place in water bath
What is the test for protein?
Add equal amount (5cm3) of biuret reagent to protein.
What is the positive result for protein test?
Lilac solution is formed
What is the test for lipids?
Add vegetable oil
Add ethanol and shake
Add to cold water
What is the positive result for lipids?
A white emulsion is formed on the surface of water.
