Dairy pt 4 Flashcards
when is phase separation of milk desirable?
when you want cream, which leads to other products like butter, ghee, and ice cream
when is phase separation of milk undesirable?
fluid milk
what formula represents the way gravity phase separation would occur?
Stoke’s formula
Stoke’s formula shows you that larger particles separated out (faster/slower)
faster
is there a relationship between viscosity and density?
no - viscosity pertains to intermolecular forces while density pertains to molecular weight
what’s the difference between the gravity and centrifugal formulae?
the centrifugal formula incorporates omega, which is not a constant; it’s based on spinning velocity
that means you can separate faster with centrifuge
what does the application of heat do to volume and density?
increases volume, decreases temp
what influences milk density?
- vitamins
- creams
- temp
- fat
increased fat means what in relation to its solids content?
more fat = less solids
list some milk products
- reconstituted milk
- filled milk
- toned milk
- lactose free milk
- low sodium milk
- flavored milks
- canned milk (evaporated, condensed)
- dehydrated milk (powders)
what’s reconstituted milk? benefits?
skim milk powders emulsified with butter fat then homogenized; can manipulate protein and fat composition; saves on transportation costs
milk –> powder –> redissolved milk
what is filled milk? benefits?
milk fat replaced with vegetable oils
- perceived health benefits (no cholesterol)
- veggie oils are cheaper which means you can sell at a lower price
what is toned milk?
milk with adjusted fat content (more fat = toned up, less = toned down)
what is lactose free milk?
milk treated with B-galactosidase to hydrolyze the lactose
- good for scrubs like me
what is low-sodium milk
useful for consumers that are on a strict, low-sodium or sodium free diet; done by passing milk through resins where sodium is remove
what are flavored milks?
chocolate, cocoa, strawberry, maple, caramel, banana (jungkook :O), vanilla
what is evaporated milk?
moisture in milk is removed by evaporation by up to 50% for convenience (storage stability, transportation, distribution)
what is condensed milk?
moisture content reduced to at least 50% then supplemented with sucrose in 45-50%; high sugar content inhibits bacterial growth
what are some examples of dehydrated milk?
skim milk powder, whole milk powder
what’s important to consider during the production of dehydrated milk products?
try to minimize protein denaturation and occurence of maillard browning; need to reduce temperature
how is dehydrated milk products produced?
- spray drying (most common)
- drum drying
- tray drying
what can be done to reduce protein denaturation and maillard browning during the production of dehydrated milk products?
- reduce temp using vacuum
- use of inert conditions (N2 or CO2 gas)
what are inert conditions?
gas that does not undergo chemical reactions under a set of given conditions; often used to stop oxidation and hydrolysis due to oxygen and moisture in the air
when milk has more fat, does it have more or less protein?
less
why do we standardize milk?
determines dollar value based on fat; quality assurance to know moisture content, total solids
describe the scheme for the processing of diary products
1) raw milk –> standardization
2. 1) standardization –> separation (forms cream and buttermilk)
2. 2) standardization –> heat treatment
3. 1) heat treatment –> pasteurized milk
3. 2) heat treatment –> fermented products (Ititu, Kefir, yogurt)
3. 3) heat treatment –> curdling/clotting
4) curdling/clotting –> whey
4. 1) curdling/clotting –> ripening –> cheese
where does ghee come from?
heated butter
where does butter come from?
heated and churned buttermilk
