milk, cheese, eggs Flashcards
what is milk?
nutrients:
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
milk proteins?
casein:
- primary protein
- extracted by acid or enzyme (rennet)
whey:
- lactalbumin and lactoglobulin
- liquid portion of milk
- separates from curd during cheese production
why do people who drink 1-3 cups of milk per day tend to have smaller waist size?
milk = high in fat and protein = higher satiety
describe lactose intolerance
genetic condition = not enough lactase enzyme = person can’t digest lactose = abdominal cramps, flatulence, nausea, diarrhea
describe milk allergy
related to beta-lactoglobulin (main protein that immune system responds to)
symptoms: vomiting, nausea, chronic cough, skin rash, headache
why is soy the only milk replacer?
protein content
why is vit D added to milk?
prevent rickets in children
prevent osteoporosis
whats the problem with reducing fat content in milk? (vit A)
vit A is fat soluble and naturally found in milk
reduced fat content = vit A lost
describe pasteurization
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
describe homogenization
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
how is yogurt made
micronutrients in milk breaks down lactose into lactic acid
how was buttermilk originally made?
liquid left from churning butter
now: enzymes are used
how is milk graded?
who grades milk
according to bacteria count
highest grade A = lowest bacteria count = safest for public
graded by USDA
milk benefits?
bone health
probiotics for gut microbiota
heart health
source of CLA (isomer of linoleic acid) = anti-carcinogeni
what hormones are used for milk?
Recombinant Bovine Somatotropin (rBST)
increases blood flow to gland = higher milk production and efficiency
can cause gland infections
banned in canada
why is milk stored in opaque containers?
b2 riboflavin is very sensitive to light
how is cheese most commonly classified?
- moisture content
- higher moisture = more susceptible of rancidity b/c of high water content = high water activity
- “fresh” = soft cheeses - milk sources: cow, goat, camel, horse, water buffalo
- processing method
macro nutrients in cheese
complete protein source
very little CHO
high fat
vit and minerals in cheese?
vit: fat soluble A and D remains in the curd. water soluble are drained in whey
minerals: Ca, P, Zn
steps in cheese production
- milk selection
- coagulation
- curd treatment
- curing
- ripening
describe coagulation by acid
texture:
- soft and spongy
- ie cream cheese
- higher pH = more solid cheese
2 methods:
- inoculate milk with bacteria
- add acid
describe coagulation by enzymes
texture
- harder/tougher
- rich in Ca
- ie. cheddar
describe curd treatment
curd is treated to remove more whey
- cutting: incr SA then strained. low moisture = smallest curd
- heating: incr whey evaporation = firmer texture = kills bacteria
- salting: dehydrates = controls bactera growth, flavor, texture, appearane
- knitting: curds melted into solid mass
- pressing: curds compacted into mass
whey products?
whey cheese, dry whey, modified whey
low fat
rich in lactose
