Cheesemaking Questions 16. We used microbial rennet (also called rennilase or rennin) to turn milk into curds and whey. a. The enzyme acts on which particular molecule in the milk? Which specific bond in that molecule does the enzyme break? b. Why does the milk curdle/form curds when those bonds are broken (in other words, what chemical reaction or change occurs in the milk once the bonds are broken)? c. The rennilase we used in the lab was made microbially, as is most rennilase used today. However, the first Western cheeses were originally made using animal rennin. What type of animal was used to harvest this rennin? Be specific about the type of animal, age of the animal, and the specific organ from which the rennin was derived. Explain the normal role of rennin in this animal, and then describe how/why having rennin benefits them. 17. Explain why we added the cultured buttermilk (which contains lactobacteria) to our milk and let it sit for at least 1 hour BEFORE we added our enzyme - what did the lactobacteria do to the milk and why is that helpful in the cheesemaking process? (Hint: Think about the specific enzyme we used to make the cheese, and what you just learned in the lab about enzyme preferences, and then think about what lactobacteria do to milk sugars and the result of that...) Enzymes in Daily Life 18. You actually use enzymes on a regular basis in your daily life - ever read the ingredients in your laundry detergent or your dishwashing detergent? Choose 2 different specific enzymes (OTHER THAN cellulase) that are used as part of laundry or dishwashing detergents, and for each one give the name and describe the function of that particular enzyme.

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