Food Tests

• Why is it important to add an excess amount of Benedict's solution?

  So that there is enough copper sulfate to fully react with any sugar present, in order to accurately determine how much sugar there is present.
• How does a Benedicts test for reducing sugars work?

  Reducing sugars can oxidise the copper sulfate ions found in Benedict's solution into copper oxide, which is not soluble in water, therefore forming a precipitate.
• In order to test for non-reducing sugars, why must we add hydrochloric acid and sodium hydrogen carbonate?

  The hydrochloric acid hydrolyses glycosidic bonds, resulting in monosaccharides that are able to reduce copper sulfate.

  The sodium hydrogen carbonate neutralises the solution for the Benedict solution to work.
• Food tests

  A) Bieuret

  B) shake

  C) lilac

  D) Benedicts

  E) 80

  F) precipitate

  G) Benedicts

  H) hydrochloric

  I) sodium hydrogen carbonate

  J) iodine

  K) blue-black

  L) ethanol

  M) shake

  N) water

  O) cloudy emulsion

  
• It is useful to hold the test tubes up against a white tile when making observations about colour