Final answer:
The presence of specific macronutrients such as fats, starch, glucose, and proteins can be detected through various color changes when using chemical indicators like Iodine solution, Benedict's solution, and the Biuret reagent.
Step-by-step explanation:
If fat is present, the Iodine solution would change from yellowish-brown to dark blue-black. Repeat for starch, glucose, and protein.
For starch, the Iodine solution would change from yellowish-brown to a dark blue-black color as well. If glucose is present, Benedict's solution would change from blue to green, yellow, or brick-red, depending on the amount of glucose. For proteins, the Biuret reagent would change from blue to pink or purple.
Important Notes:
- Fats and oils are in a more reduced form than glycogen and release more energy per mass upon oxidation.
- Glycogen is hydrophilic and absorbs water, which increases its mass.
- Enzymes such as amylases break down starch into glucose units in a process involving the intermediate products dextrins and maltose.
- Animals use glycogen and fats for storage, whereas plants use starch for this purpose.