Loading presentation...

Present Remotely

Send the link below via email or IM

Copy

Present to your audience

Start remote presentation

  • Invited audience members will follow you as you navigate and present
  • People invited to a presentation do not need a Prezi account
  • This link expires 10 minutes after you close the presentation
  • A maximum of 30 users can follow your presentation
  • Learn more about this feature in our knowledge base article

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.

DeleteCancel

Make your likes visible on Facebook?

Connect your Facebook account to Prezi and let your likes appear on your timeline.
You can change this under Settings & Account at any time.

No, thanks

Food Tests

Brief description of main food tests.
by

Brigita Biondic

on 22 November 2016

Comments (0)

Please log in to add your comment.

Report abuse

Transcript of Food Tests

Carbohydrates:
1. Glucose: Benedict Test
Lipids / Fats:
When a sample containing fats is pressed or rubbed on a clean white sheet of paper, a greasy spot (translucent spot) appears.
Proteins:
Biuret solution is used to identify the presence of protein. Biuret reagent is a blue solution that, when it reacts with protein, will change colour to mauve-purple.
Major food types are:
1: Carbohydrate
2:Fats
3: Proteins
FOOD TESTS
HOW TO PERFORM TESTS FOR DIFFERENT TYPES OF FOOD
2. Starch: Iodine Test
Positive test gives dark purple - black colouring on the sample.
1.Take small amount of crushed food sample or 10 drops of aqueous solution of the sample in a test tube.
2. Add 3-4 drops of iodine solution.
3. Note any color change.
Benedict's solution is a clear blue solution that in the presence of simple sugars will change color to green, yellow, and brick-red, depending on the amount of sugar.
1. To a test tube, add food sample to be tested.
2. If testing more than one liquid, label each test tube with a marker.
3. Add 10 drops of Benedict's solution to each test tube.
4. Carefully heat the test tubes by suspending in a hot water bath for five minutes.
5. Note any color change.
Spot test using a filter paper:
1.Take a food sample to be tested and press or rub it on a clean white sheet of paper.
2.Hold it against light to see if the paper become transparent or not.
Biuret Test:
1.Take small amount of crushed food sample in a test tube.
2.If testing more than one liquid, label each test tube with a marker.
3.Add 3 drops of Biuret reagent solution to each test tube. Shake gently to mix.
4.Note any color change.
Biuret Solution contains the same amount of sodium hydroxide and copper sulfate solution.
Full transcript