Lecture 15: Milk, Dairy, and Cheese Flashcards Preview

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Flashcards in Lecture 15: Milk, Dairy, and Cheese Deck (68):
1

Kumiss

Commonly produced in Russia from raw mare's milk

2

Kefir

-Milky beverage fermented from cows by Balkans
-Commonly produced in Southwest Asia
-Basically watered down flavored yogurt

3

What is the Greek word for "milk drinkers"?

Galaktopotes

4

When did the colonists introduce dairying to America?

1625

5

By what year did dairying become a modern industry?

1850

6

What is milk?

A white, opaque fluid of female mammals for the total sustenance of their offspring

7

Colostrum

-First fluid secreted by the mammary glands of female mammals
-Clear solution of concentrated protein, vitamins, and antibodies

8

What factors affect how milk's composition varies?

-Species of cow (size, genetics)
-Region, climate, season
-Type of feed
-Care for animals

9

Common dairy breeds

-Holstein
-Brown Swiss
-Guemsey
-Jersey

10

What are the 2 types of milk proteins?

-Caseins
-Whey proteins

11

What determines the type of milk protein?

Their reaction with acid or chymosin (rennin)

12

What do caseins form?

Curds, clumps

13

What are micelles formed from?

Casein and minerals (phosphate, calcium) in milk

14

What causes casein particles to clump/curdle?

Chymosin or acid

15

How is cream made? (2 ways to do this)

Separation of fat globules from the water phase
-fat globules rise b/c it's less dense than water
-separated by centrifuge

16

Who developed pasteurization?

Louis Pasteur

17

Why was pasteurization first developed?

To prevent wine and beer from spoiling

18

Difference between pasteurization and sterilization

-Pasteurization reduces number of microorganisms, but doesn't kill them all
-Sterilization kills all microorganisms

19

What are the 2 time/temp combos for milk to be pasteurized?

-144 F for 30 mins
-160 F for a few secs

20

HTST

High Temp Short Time pasteurization (160 F for a few secs)

21

UHT

Ultra High Temp pasteurization
-doesn't sterilize milk product, but drastically reduces # of microorganisms
-extends shelf life
-gives milk product cooked lavor

22

What does homogenization do to milk?

Breaks down the fat globules to prevent them from rising to form a separate layer of cream on the top

23

How is milk homogenized

Milk is forced through a small nozzle onto a hard surface

24

How much fat does whole milk have?

4%

25

Why does milk have to be fortified?

When fat is removed, other lipids including fat-soluble vitamins go with it

26

What does fortification add to milk?

Fat-soluble vitamins A & D

27

What are the modern concerns surrounding milk products?

-Use of antibiotics
-Use of hormones

28

What causes cream to be whipped?

-Foam of air in water
-Proteins stabilize the air bubbles
-Fat increases the viscosity of the liquid

29

What happens if the cream is whipped past the stiff phase?

-Phase reversal to butter
-Butter squeezes out all the water --> produces butter and buttermilk

30

Churning butter

Churning breaks the bubble structures and collapses the fat globules together to form butter and the liquid residue (buttermilk)

31

What makes butter yellow?

Natural vitamin A

32

Why is butter packaged in aluminum?

Keeps the light out --> light causes rancidity

33

What affects the quality of butter?

Ratio of amorphous (free) fat to crystallized fat

34

Tempering

Process of using different temps to ensure different kinds of crystals form in food
-important for texture

35

Why is salt added to butter?

-Preservative
-Enhances taste

36

What percentage of butter is the liquid water portion?

16%

37

What part of the butter becomes rancid? Why?

Liquid water portion can harbor bacteria and start turning rancid

38

What is the original origin and purpose of margarine?

-Goal was to produce a food easy to carry that provided a lot of calories for Napoleon's armies

39

Today, how is margarine made?

-Made of hydrogenated (partially saturated) vegetable oils
-Emulsified with cultured skim milk
-Flavored and colored

40

What is a concern surrounding margarine?

Trans fats

41

Fats vs. Oils

-Oils = unsaturated fatty acids; liquid at room temp
-Fats = saturated fatty acids; solid at room temp

42

Through what process is vegetable oil converted to margarine?

Catalytic hydrogenation

43

How does catalytic hydrogenation convert vegetable oil to margarine?

Saturates some of the double bonds --> partial hydrogenation

44

Downside of catalytic hydrogenation

Converts cis-unsaturations to trans-double bonds --> TRANS FAT

45

In essence, what is ice cream?

A foam stabilized by freezing the liquid phase

46

4 component phases of ice cream

-Liquid containing sugar, protein, salts
-Ice crystals
-Fat globules
-Air cells

47

What is undesirable when making ice cream?

Lactose crystals

48

What does the law require for a food to be labeled "ice cream"?

-10% milk fat
-20% total milk solids
-<4.5 lbs per gallon (weight)

49

What are major factors that determine quality and price of ice cream?

Fat and air content

50

Standard of Identity

Code of Federal Regulations spells out exactly what standards a product must have to be labeled a certain food name

51

Creaming

Process of removing milk fat, usually via a centrifuge

52

What milk products are fermented?

All curdled milk products

53

How does fermentation prevent/retard undesirable spoilage and pathogens?

-Producing acid
-Competing for nutrients

54

Starter culture

Bacterial agent added to milk to assure a good fermentation

55

Probiotic

Live strains of good bacteria that help our digestive system work efficiently

56

Prebiotic

Nutrients bacteria feed on to increase their numbers

57

Synbiotic

Products are both probiotic and prebiotic

58

Acidophilus milk

-Fermentation replaces some lactose with lactic acid --> sour taste
-Lactose intolerant peeps can drink it b/c less lactose than regular milk

59

How is today's buttermilk made?

Not drawn off butter churn, but cultured low-fat or skim milk

60

What is yogurt made from?

Whole or skim milk plus dried milk solids

61

Who popularized yogurt?

Elie Metchnicoff

62

How was cheese discovered?

-When the fourth stomach of a milk-fed calf was used as a vessel for carrying milk
-Stomach contained rennet
-Rennet causes solids to separate from liquids in milk

63

Rennet

An extract of milk-fed calves' fourth stomach

64

Cheddaring

Curds cut into blocks and piled up

65

How are cheeses prepared for ripening?

Surface is often coated with waxes or other materials to protect the cheese within

66

"Green" cheeses

Unripened cheese

67

What determines the hardness of cheeses?

Water content

68

For ice cream, the term "overrun" refers to ___?

Air content