Food Chemistry / Digestion Lab
Separating & Testing Components of Milk
Answer these questions:
1. What does Iodine test for and what color indicates the strongest positive test?
2. What does the Biuret reagent test for and what color indicates the strongest positive test?
3. What does the Benedict reagent test for and what color indicates the strongest positive test?
4. What does the Sudan III stain test for and what color indicates the strongest positive test?
5. What would be a good negative control for all of these tests (same for all tests)?
6. What would be a good positive control food for each of these tests (different for each test)?
7. Why do we use a negative control?
8. Why do we use a positive control?
Circle the correct answer/answers or leave blank if no correct answers:
9. Is there sugar in whole milk? yes no
10. When you separate milk into whey and curds, where is the sugar? whey curds
11. Is there starch in whole milk? yes no
12. When you separate milk into whey and curds, where is the starch? whey curds
13. Are there lipids in whole milk? yes no
14. When you separate milk into whey and curds, where are the lipids? whey curds
15. Is there protein in whole milk? yes no
16. When you separate milk into whey and curds, where is the protein? whey curds
17. Which contains more protein? whey curds
18. Which of the 4 macromolecules are found in whole milk?
19. Which of the 4 macromolecules are found in cheese?
20. Traditionally, whey was considered a waste product of cheese production, although farmers would often feed it to
their pigs. Search the internet and list a few ways whey is used now so that it isn’t wasted.
21. Animal rennet works best from 85 – 105 degrees Farenheit (29 – 41 degrees Celcius) and also works best in an acid
(low pH) environment. Why? (Think about where it comes from).
22. Why do we get animal rennet from calf stomachs? (What is it about them that causes it to work?)
23. Did you produce more curds from skim or whole milk? What caused the difference in curd yields?
24. Were there any other differences in the curds produced from skim versus whole milk?
