milk, cheese, eggs

Question 1

what is milk?

nutrients:

Answer 1

emulsion of fat globules and a suspension of casein micelles suspended in an aqueous milk serum phase

secreted from the mammary gland to serve as nutrition for the newborn

source of: complete protein, b vit, vit A, vit D, Ca

lacking: vit C and E, Fe, complex CHO

Question 2

milk proteins?

Answer 2

casein:

• primary protein
• extracted by acid or enzyme (rennet)

whey:

• lactalbumin and lactoglobulin
• liquid portion of milk
• separates from curd during cheese production

Question 3

why do people who drink 1-3 cups of milk per day tend to have smaller waist size?

Answer 3

milk = high in fat and protein = higher satiety

Question 4

describe lactose intolerance

Answer 4

genetic condition = not enough lactase enzyme = person can’t digest lactose = abdominal cramps, flatulence, nausea, diarrhea

Question 5

describe milk allergy

Answer 5

related to beta-lactoglobulin (main protein that immune system responds to)

symptoms: vomiting, nausea, chronic cough, skin rash, headache

Question 6

why is soy the only milk replacer?

Answer 6

protein content

Question 7

why is vit D added to milk?

Answer 7

prevent rickets in children

prevent osteoporosis

Question 8

whats the problem with reducing fat content in milk? (vit A)

Answer 8

vit A is fat soluble and naturally found in milk

reduced fat content = vit A lost

Question 9

describe pasteurization

Answer 9

regular:

• heat milk below bp for short time = reduce foodborne illness
• destroys 95-99% of bacteria
• most common

ultra:

• high temp for short time
• 15s
• extends shelf life

ultra high

• 2seconds
• sterile packaging

Question 10

describe homogenization

Answer 10

when milk is raw = fat floats on top

mechanical process. no effect on nutritional value

reduce size of fat globules = evenly distributes fat throughout mixture =homo milk tastes creamier

Question 11

how is yogurt made

Answer 11

micronutrients in milk breaks down lactose into lactic acid

Question 12

how was buttermilk originally made?

Answer 12

liquid left from churning butter

now: enzymes are used

Question 13

how is milk graded?

who grades milk

Answer 13

according to bacteria count

highest grade A = lowest bacteria count = safest for public

graded by USDA

Question 14

milk benefits?

Answer 14

bone health
probiotics for gut microbiota
heart health
source of CLA (isomer of linoleic acid) = anti-carcinogeni

Question 15

what hormones are used for milk?

Answer 15

Recombinant Bovine Somatotropin (rBST)

increases blood flow to gland = higher milk production and efficiency

can cause gland infections

banned in canada

Question 16

why is milk stored in opaque containers?

Answer 16

b2 riboflavin is very sensitive to light

Question 17

how is cheese most commonly classified?

Answer 17

1. moisture content
   - higher moisture = more susceptible of rancidity b/c of high water content = high water activity
   - “fresh” = soft cheeses
2. milk sources: cow, goat, camel, horse, water buffalo
3. processing method

Question 18

macro nutrients in cheese

Answer 18

complete protein source

very little CHO

high fat

Question 19

vit and minerals in cheese?

Answer 19

vit: fat soluble A and D remains in the curd. water soluble are drained in whey
minerals: Ca, P, Zn

Question 20

steps in cheese production

Answer 20

1. milk selection
2. coagulation
3. curd treatment
4. curing
5. ripening

Question 21

describe coagulation by acid

Answer 21

texture:

• soft and spongy
• ie cream cheese
• higher pH = more solid cheese

2 methods:

1. inoculate milk with bacteria
2. add acid

Question 22

describe coagulation by enzymes

Answer 22

texture

• harder/tougher
• rich in Ca
• ie. cheddar

Question 23

describe curd treatment

Answer 23

curd is treated to remove more whey

1. cutting: incr SA then strained. low moisture = smallest curd
2. heating: incr whey evaporation = firmer texture = kills bacteria
3. salting: dehydrates = controls bactera growth, flavor, texture, appearane
4. knitting: curds melted into solid mass
5. pressing: curds compacted into mass

Question 24

whey products?

Answer 24

whey cheese, dry whey, modified whey

low fat
rich in lactose

Question 25

function of eggs

Answer 25

1. emulsification: gg yolk has lecithin
2. binding
3. foaming (fresh eggs are better b/c thicker egg whites)

Question 26

describe structure of eggs

Answer 26

yolk:
- 1/3 of egg weight
- color of yolk depends of hen’s diet
- beta carotene

albumen (egg white)

• 58%of egg weight
• h2o and protein

chalaza:
-anchors egg yolk to center of egg white

shell:

• 12% of egg weight
• contains tiny pores to allow gas exchange

air cell:

• fresher egg = smaller air cell
• provides chick to breath needed to break out of shell

Question 27

describe nutrition of egg

Answer 27

pro: 7g total. (3 from yolk)
fat: MUFA and SA
chol: 213mg

vit: DEAK
b2 b12 folate biotin pantothenic acid

min:
Fe is not bioavailable

Question 28

primary protein in egg white?

Answer 28

ovalbumin

-denatures easily

Question 29

why should you not eat egg white raw?

Answer 29

contains avidin = likely to be contaminated

Question 30

egg yolk fats and pigments?

Answer 30

fats:
TG, phospholipid, chol

pigments:
carotenoids, xanthophyll, lucpene, litein, zeaxanthin

Question 31

how is omega 3 added to eggs?

Answer 31

fish oil

Question 32

how are low chol eggs produced?

Answer 32

hens diet (high fiber and low fat)

Question 33

how does stress affect eggs?

Answer 33

stress in chickens = smaller eggs

thus free run = less stress = bigger eggs

Question 34

how is egg quality measured?

Answer 34

“candling”: putting egg to light to see clarity

Question 35

why are eggs stored in container?

Answer 35

to minimize gas exchange

Question 36

salmonella and listeria in eggs?

Answer 36

egg shells are exposed to salmonella

listeria = can grow in fridge temp