Protein with biuret added turns purple. (Biuret pronounced buy-your-et)
The protesting teenagers (proteins) said: “We’ll buy your eggs” (biuret), but the shop would not sell them any because they would be used for protesting. The protesting teenagers turned purple with rage.
The test for protein:
Add Benedict’s solution to some food in a test tube. Boil for 5 minutes. If glucose is present the colour turns green (if only trace amounts present), then orange-red if the concentration of glucose is greater.
If glucose is drunk by him, Big Ben predicts (Benedict’s) that the traffic lights at his foot will change to green then orange and red.
The test for glucose:
Add orange-brown iodine to some food. If starch is present the colour changes is to blue-black.
I could see stars (starch) after I was beaten black and blue, just because I dined (iodine) on oranges!
The test for starch:
Fats (lipids) go cloudy white when mixed with ethanol and water.
Fat mama (fats) and her white poodle (ethanol) are in the rain (water) and Fat Mama’s lips (lipids) turn white. To remember that white poodle means ethanol, click here
The test for lipids.
Dissolve the food in ethanol and filter. Add water. Observe a white emulsion if lipids are present.