Food Tests Flashcards
What do you use the Benedict’s test for?
You use it to test for sugars.
What do you use Iodine Solution for?
You use it to test for starch.
What do you use the Biuret Test for?
You use it to test for proteins.
What do you use the Sudan III test for?
You use it to test for lipids.
How do you carry out the Benedict’s test?
1) Prepare a food sample and transfer 5cm^3 to a test tube.
2) Prepare a water bath so that it’s set to 75*c
3) Add some Benedict’s solution to the test tube using a pipette
4) Place the test tube in the water bath using a test tube holder and leave it in there for 5 minutes - Make sure the tube is pointing away from you.
5) If the food sample contains a reducing sugar, the solution in the test tube will change from blue to green, yellow or brick-red - depending on how much sugar is in the food.
How do you carry out the Iodine Solution test?
1) Make a food sample and transfer 5cm^3 of your sample to a test tube
2) Add a few drops of iodine solution and gently shake it to mix the contents. It there is starch then the colour of the solution will change from browny-orange to black or blue-black.
How do you carry out the Biuret test?
1) Prepare a sample of your food and transfer 2cm^3 of your sample to a test tube
2) Add 2cm^3 of biuret solution to the sample and mix the contents by gently shaking it
3) If the food sample contains protein, the solution will change from blue to purple - if not then the solution will stay blue
How do you carry out the Sudan III test?
1) Prepare a sample of food and transfer 5cm^3 into a test tube
2) Use a pipette to add 3 drops of Sudan III stain solution to the test tube and gently shake it to mix it
3) If the sample contains lipids the mixture will separate into 2 layers - the top layer will be bright red - if there are no lipids present then no separate red layer will form
