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1. What purpose is served by filtering the milk sample after the addition of aci

ID: 1040142 • Letter: 1

Question

1. What purpose is served by filtering the milk sample after the addition of acid?

2. Many cheese making processes use enzymes instead of acid to help create cheese. What purpose is served by the enzyme in this instance?

Discussion Questions

1. When weighing the protein at the end of the activity, what is a major assumption that is made about the product? Why might this impact the calculated percentage of casein in the sample?

2. If a base such as sodium hydroxide were added to milk, would the protein precipitate? Why or why not?

Explanation / Answer

1)

Casein is a milk protein and has an isoelectric point(pH where net charge on the molecule is of 4.6 i.e it is immutable in assay solvent whose pH is less than 4.6 pH ofmilk is around 6.6,so it is present as calcium caseinate.

Calcium caseinate +H+->Ca^2+casein

On the addition of acid,antionic form as casein gets neutralized due to the decrease in the pH,precipitates out.Thus,filtration is used to remove this precipitates from milk liquids.