Chapter 10

Question 1

Whole milk composition

Answer 1

87% water an 13% fat

Question 2

What aspects of cow can change fat content and protein of milk ?

Answer 2

Breed of cow , intake of fiber and non fiber carbs

Question 3

Milk is a solution , oil in water emulsion and a colloidal dispersion , why ?

Answer 3

Oil droplets , casein Micelles, lactose and whey protein

Question 4

Lactose is what type of carbohydrate ?

Answer 4

Disaccharide

Question 5

Relative sweetness of lactose

Answer 5

0.35

Question 6

How common is lactose intolerance in the world ?

Answer 6

~70 % of adults lack enzyme

Question 7

Why does casein form micelles ?

Answer 7

Uneven distribution of charged amino acids

Question 8

What 2 things can cause casein micelles to aggregate and precipitate ?

Answer 8

Lower ph and enzyme chymosin/rennet

Question 9

How is casein coagulation implicated in yogurt and cheese ?

Answer 9

Casein micelles aggregate to
form gel strands

Question 10

Rough fatty acid composition of milk

Answer 10

2.7 percent trans fat, 69.4 sat fat , 8 percent scfa

Question 11

What is the MFGM, and why is it significant to the properties of milk? How does it play a role in whipped cream and butter?

Answer 11

Milk fat globule membrane. It helps the milk to remain a stable emulsion for days. Allows cream and butter not to fall apart

Question 12

What are the primary 3 mechanism through which milk spoils

Answer 12

Microbial growth, lipid hydrolysis , lipid oxidation

Question 13

The mechanisms that milk spoils, and the chemicals produced that are so off-putting, are also important parts of the fermentation process to produce things like yogurt and cheese, which are generally well-liked. How can this be?

Answer 13

Both are fermented foods that use microbial growth to create new flavors within the food. Balance and context is key

Question 14

What types of microbes are generally used to make yogurt ?

Answer 14

Lactic acid bacteria

Question 15

What chemical/physical changes occur (basic level - no need to know specific chemicals) in yogurt and cheese that gives it its key properties, texture or flavor?

Answer 15

Lactose hydrolyzed
• Increase in digestibility
Fermentation of sugars
• Flavor compounds produced
pH reduction
• Precipitation/coagulation of casein
Lipid hydrolysis
• Free fatty acids released

Question 16

Cheeses can be so different from one another, what are the main factors that affect the final product of cheese?

Answer 16

Flavors of each cheese comes from unique microbes

Question 17

What is the process of homogenization? What is the purpose of doing it?

Answer 17

Fluid milk forced through small holes at high pressure
Reduces fat globule size and allows it to not separate

Question 18

What is the process of pasteurization? What is the purpose of doing it?
Does pasteurization kill all microbes?

Answer 18

Controlled heat treatment that does not kill all microbes and destroys pathogens as well as increases chela life

Question 19

How is ultra-pasteurization, UHT, and sterilization different from regular pasteurization?
How do they affect shelf life? What products are they used for?

Answer 19

They are both at higher temperatures 138 c and allow for more months of shelf life. Used for creamer and creams

Question 20

Why is there some controversy surrounding dairy production? What are some of the ethical and sustainability concerns that may be valid?

Answer 20

Environmental water and land use as well as green house gas emissions. Artificial insemination

Question 21

What are some common plant-based substitutes for fluid milk?

Answer 21

Soy milk, ripple