- Created by: Bulberman
- Created on: 09-11-18 19:42
Preparing For Food Tests
1)Get a piece of food and break it up using a pestle and morar.
2)Transfer the ground up food to a beaker and add some distilled water.
3)Give the mixture a good stir with a glass rod to dissolve some of the food.
4)Filter the solution using a funnel lined with filter paper to get rid of the solid bits of food
You use Benedict's Test
1) Prepare a food sample(refer to preparing for food tests card) and transfer 5cm^3 to a test tube
2)Prepare a water set to 75 degrees celsius
3)Add about 10 drops of Benedict's Solution to the test tube.
4)Place the test tube in the water bath and leave it there for 5 minutes. Make sure it's pointing away from you for safety reasons.
5)If the food sample contains sugar, it will chang to green, yellow or brick-red but it depends on how much sugar is in the food.
You use iodine solution
1) Make a food sample and tranfer 5cm^3 of it into a test tube.
2) Add a few drops of iodine solution and gently shake it. If it contains starch the colour will change from browny-orange to black/blue-black.
You use the biuret test.
1) Prepare a sample of your food and transfer 2cm^3 of your sample to a test tube.
2) Add 2 cm^3 of biuret solution to the sample and gently shake the test tube.
3)If the food sample contains protein, the solution will change from blue to purple.
You use Sudan III test for Lipids.
1)Prepare a sample of the food(you don't need to filter it) Transfer about 5cm^3 into a test tube.
2)Use a pipette to add 3 drops of Sudan III stain solution and gently shake the tube.
3)Sudan III stains solutions, so if the solution contains lipids it will split into two layers. The top layer will be bright red like a brick, however if there are no lipids present, there will be no seperate red layer.