Food tests

Question	Answer
what does iodine test for?	It tests for starch and you know it is present if the colour changes from browny-orange to black or black-blue.
What do you use to test for proteins?	You do the Biuret test by mixing 2cm cubed of a sample of food mixed with 2 cm cubed of Biuret solution. If the solution turns pink or purple from a blue colour than protein is present.
What is the Benedict test?	It tests for sugars and the method is: 1- prepare a food sample and transfer 5cm cubed into a test tube. 2- Prepare a water bath at 75 degrees 3- Add around 10 drops of benedict's solution to the test tube with the food sample. 4- Place the tube in the water bath and leave it there for 5 mins. 5- If there is sugar present the solution will turn from blue to green, yellow or red (depending on how high the content of sugar there is)
How do we test for Lipids?	The Sudan 3 test is used by: 1- preparing a 5 cm cubed sample in a test tube 2- use a pippet to place 3 drops of sudan 3 stain solution into the test tube and shake gently. 3- If lipids are present then it will sepourate into two layers will form and the top layer will be bright red.

Resource summary

	Created by Grace Marks over 6 years ago