biochemical composition of milk Flashcards
factors that affect milk production and composition (5)
breed and species
feed/pasture
season/ temp
point of milking (fore/hind milk)
stage of lactation
whta % of milk is milk solids
13%
what are milk solids comprised of
fat
protein
enzymes
carbohydrates
minerals
vitamins
what % of milk solids is fat
4%
what % of milk solids consist of protein, carbs, minerals, vitamin, enzymes and organic acids
9%
what % of milk is water
85-87%
what properties does water give to milk
medium for milk solids
medium for dispersion of insoluble milk proteins
physical properties (conductivity)
affects shelf life
what % of milk fats are triglycerides
98%
what is the most variable component of milk
milk fats
role of fat in milk
yellow colour from beta carotene
smooth mouth feel
calories
nutrients
flavour
distribution of milk proteins
whey 18%
casein 80%
other proteins/ non-nitrogen protein 2%
% composition of caseins
alpha s-1 - 32.4%
alpha s-2 - 8.5%
kappa - 9.4%
beta - 26.1
gamma - 2.4
what is meant by casein proteins being conjugated
bound to Ca phosphate and aggregated into micelles
why cant casein micelles be denatured by heat
disordered secondary structure
% composition of cow milk whey
beta-lactoglobulin 9.8%
alpha-lactalbumin 3.6%
immunoglobulin 2.4%
bovine serum albumin 1.2%
protease peptone 2.4
miscellaneous 1.8
why does casein have a disorganised secondary structure
high levels of proline cause bending
role of alpha lactalbumin
controls lactose synthesis
why does casein have a disorganized secondary structure
high levels of proline cause bending
role of alpha lactalbumin
controls lactose synthesis
role of beta lactoglobulin
no known biological function (not in human milk)
role of bovine serum albumin
biochemical assay
what does the cleavage of B-casein form
gamma-casein(hydrophobic) +proteose peptones (hydrophillic)
indigenous enzymes in raw milk
lipases, lysoszymes, esterase, proteinases, catalases, lactoperoxidases, xanthin oxidase, phophatase
role of lipases
rancidity in milk
