14. Dairy Products

Question 1

What gives skim milk a slight bluish tint?

Answer 1

Riboflavin;

Question 2

The lactic acid in cheese is made from what compound?

Answer 2

Lactose;

Question 3

What are the consequences when milk is overheated?

Answer 3

Denaturation/coagulation and sulfur release;

Question 4

Give the names of two major breeds of dairy cattle.

Answer 4

Holstein/Jersey/Brown Swiss/Guernsey;

Question 5

Where are lipovitellins and livetins found?

Answer 5

Plasma proteins of egg yolk;

Question 6

In cheese production why is rennet added after pH has been slightly reduced by the starter cultures?

Answer 6

The activity of clotting enzymes (rennet) is higher in acid media;

Question 7

Which cheese is made from the by-product of cheese production?

Answer 7

Ricotta Cheese;

Question 8

Skim milk has a bluish tint due to the scattering of light by what component?

Answer 8

Casein micelles;

Question 9

What are the major components of bovine milk and what are their approximate percentages?

Answer 9

Water-87% / Lactose- 4-5% / Fat- 4% / Protein-3.5% / Minerals- 0.7%;

Question 10

What is the monosaccharide in milk?

Answer 10

Galatose and glucose;

Question 11

What are two ways milk is dried into powdered form?

Answer 11

Spray drying and roller drying.;

Question 12

What is the white color and yellow color of milk due to?

Answer 12

Whiteness is due to scattering of light by casein micelles and fat globules. Yellow is due to the fat-soluble pigment.;

Question 13

What are the two major whey proteins in milk and what percentage of total milk protein do they make up together?

Answer 13

Beta-lactoglobulin & alpha-lactalbumin; together they make up about 20% of milk proteins.

Question 14

Lactose is commonly isolated from whey. Name two ways this can be accomplished.

Answer 14

Crystallization or Nanofiltration;

Question 15

What milk protein is responsible for iron binding and enhanced iron absorption into the body?

Answer 15

Lactoferrin;

Question 16

Whey protein concentrate (WPC) is produced with three different protein percentages. What are they?

Answer 16

34% - 50% - 80%;

Question 17

What is the major protein group in milk?

Answer 17

Casein;

Question 18

What is the name of the controversial hormone given to dairy cows to increase milk production?

Answer 18

Bovine Somatotropin or Bovine Growth Hormone;

Question 19

What does MFGM stand for?

Answer 19

Milk Fat Globule Membrane;

Question 20

What are the approximate molecular weights of alpha-lactalbumin/beta-lactoglobulin/bovine serum albumin (BSA)?

Answer 20

Alpha-lactalbumin= app. 14200 Da / Beta-lactoglobulin= app. 18400 Da / BSA= app. 69000 Da;

Question 21

What hydrocolloid’s largest use is a stabilizer in chocolate milk and ice cream?

Answer 21

Carrageenan;

Question 22

Which milk product is concentrated to 2.25 times the solids of normal milk then sterilized in cans in continuous pressure retorts at 245F for 15 minutes?

Answer 22

Evaporated Milk;

Question 23

The detection of coliforms in a sample of pasteurized milk purchased from the grocery store would indicate what about the milk?

Answer 23

Probably post-pasteurization contamination (inadequate pasteurization is also acceptable);

Question 24

Name the two principal whey proteins.

Answer 24

Beta-lactoglobulin and alpha-lactalbumin;

Question 25

What is direct acid set cottage cheese?

Answer 25

Cottage cheese made with food grade organic acids rather than bacteria starter cultures.;

Question 26

Define percent overrun in ice cream.

Answer 26

The volume of frozen/finished ice cream in excess of the volume of the liquid mix.;

Question 27

The compound responsible for the characteristic buttery flavor of fermented dairy foods is what?

Answer 27

Diacetyl;

Question 28

What is the legal percentage of butter fat to be classified as whole milk?

Answer 28

0.0325;

Question 29

If whey proteins are heated what three changes can be observed?

Answer 29

Coagulation/Denaturation/Maillard Browning;

Question 30

Acid that is present in milk due to proteins-phosphates-carbonates-citrates rather than from bacterial fermentation is known as what?

Answer 30

Apparent Acidity;

Question 31

What is rennin?

Answer 31

Proteolytic enzyme from the stomach of suckling calves.;

Question 32

Cow's milk normally contains how much lactose?

Answer 32

5% by weight;

Question 33

Whey normally contains how much lactose?

Answer 33

5% by weight;

Question 34

What is the function of gelatin in an ice cream mix?

Answer 34

Stabilization-it retards ice crystal formation during frozen storage of the finished product.;

Question 35

What is butter without salt called?

Answer 35

Sweet Butter;

Question 36

What compound is commonly used to color cheese?

Answer 36

Annatto Extract;

Question 37

In dairy cows aflatoxin B1 can be ingested with feed. A small percentage of this toxin is metabolized and excreted in milk as what?

Answer 37

Aflatoxin M1;

Question 38

What is cheddaring?

Answer 38

The process where matted cheese curd is cut into blocks stacked and drained of whey.;

Question 39

What is the most prudent and practical means of processing milk in third world countries?

Answer 39

Ultra-high temperature (UHT);

Question 40

What makes milk white?

Answer 40

The casein micelles which scatter light.;

Question 41

Name the common flavor defect found in milk exposed to light?

Answer 41

Light oxidized flavor;

Question 42

Differentiate between evaporated and condensed milks.

Answer 42

Condensed milk is processed similarly to evaporated milk except it may be homogenized and/or vitamin D fortified. It is not subjected to further heat treatment.;

Question 43

Cheddar is America's favorite cheese. What is second?

Answer 43

Mozzarella;

Question 44

Which cows produce the most milk?A) Jerseys B) Guernseys C) Holsteins

Answer 44

C. Holsteins;

Question 45

Name a good natural source for the enzyme Xanthine Oxidase.

Answer 45

Milk;

Question 46

Which cows produce milk with higher fat content: Hosteins or Jerseys?

Answer 46

Jerseys;

Question 47

What kind of milk is Roquefort cheese made from?

Answer 47

Sheep's Milk;

Question 48

What proteolytic enzyme is used in cheese production?

Answer 48

Chymosin or Rennin;

Question 49

What is the amino acid that is most responsible for off-flavor development in milk?

Answer 49

Methionine;

Question 50

Name the four major categories of cheese.

Answer 50

Soft unripened - Soft ripened - Semisoft ripened - Hard.;

Question 51

What are the two steps in rennet coagulation of milk?

Answer 51

Enzymatic cleavage of K-Casein + aggregation and gelation of caseins.;

Question 52

The lactose content in human milk is higher than in cow milk?

Answer 52

TRUE;

Question 53

On a weight percent basis what are the two predominant fatty acids in cow's milk?

Answer 53

Palmitic (24-26%) and Oleic (34-38%)