Testing for starch
Add 4 drops of Iodine to the ground up food, or a solution of it..........
If STARCH is present it will produce a BLUE/BLACK colour.
Testing for simple sugars
Add 8 drops of Benedict's reagent to the food sample, this will make it go pale BLUE. Heat the boiling tube in a beaker of hot water.......
.......if SIMPLE SUGARS are present the sample will change from BLUE to GREEN to YELLOW to RED!
Testing for Protein
Add about 5cm3 of very dilute sodium hydroxide, then add a similar amount of dilute copper sulphate solution to the sample in solution.........
......If PROTEIN is present it will produce a PURPLE colour
Testing for Fat
Shake the food sample up with about 10cm3 of ethanol in a dry test tube, then carefully pour some of this into a test tube containing 10cm3 of water........
.......If FAT is present the water will become a CLOUDY WHITE colour.
End of Cards