Proteins Flashcards
protein sources
eggs dairy meat poultry fish grains nuts legumes
elements in protein
c
o
h
n
two ways of classifing proteins
- fibrous/globular
2. primary, secondary, etc.
composition of a protein
carboxyl
amine
r-side
formation of amino acids joined by a peptide bond (dehydration synthesis) to produces peptides
r group examples
methionine glcine leucine valine isoleucine
primary proteins
simple AA sequence
peptide bonds
secondary proteins
alpha helix/b pleated sheets
hydrogen bonds
tertirary proteins
3d folding of polypeptides
h bond/ionic bond/disuliphide and hydrophobic interations
quaternary proteins
macromoleucles of multiple popypeptide units
i.e. haemoglobin
fibrous/flobular structures
h bond/ionic bond/disuliphide and hydrophobic interations
fibrous proteins
stuructural
animal origin
insoluble
i.e. kertain, collagen, silk
globular proteins
functional
water soluble
spherical
i.e. hormonzes, enyzme, storaga, carriers
non essential amino acids
11 AA we don’t need unless we’re an infant for growth or having a specific condition
essential amion acids
body uses 20 AA to make proteins; of which 8 are needed from food
what are the 8 AA
leucine valine lysine isoleucine methiodine threonne phenylaline tryptophan
most deficient AA
lysine
methione
denaturation
heating/chemical additives that changes the nature of a protein structure
coagulation
clumping together of proteins
causes milk to clot/egg to cook
rennent
coagulates milk into cheese; taken from a calf stomach or from thistle flowers
function of a protein in food
- gelling agent
- emulsifier
- texturizer (by denaturation; makes vegan products)
gluten
gliadin and glutenin protein complex that in some people causes coelic disease
gluten sources
wheat pasta cookies beer ale cous cous malted foods
gluten free grain
rye quinoa millet amaranth buckwheat sorfgum
why might gluten not be healthy
higher in fat, sugar, calories
lower in fibre, b vitamins folate iron
can cause conspitation, cancer and damage gut
what are human protein needs
lysine and methionine (mainly; key 8 proteins)
what are complementary proteins
combination of lysine/methionine foods to form complete protein requirements; hence legumes (high methione) + beans (high lysine) eaten together globally (hummus and pita, etc. )
how can one determine protein quality
- digestability
- aa composition
- essentiall aa composition
measured by:
BV
PER
BV
biological value: body retention of the protein
aa used/absorved x 100
eggs have highest, milk/beef/soy medium, lentils least
PER
protein efficency ratio; ability of protein to support growth
BCAAS
branched chain amino acids (leucine, isoleucine, caline) that support muscle growth/protein synthesis
often sold as supplements
high protein diet: good or bad?
cuaes nitrogen posioning [kidney/liver damage]; we only need 2 kg per day but usually body builders at 4-6 kg per day
KETO DIET BAD
liebig limit
to build a tissue, if even 1 nutrient is missing you can’t build it
organic eggs
code= 0 cage free no antibiotics access to outdoors organic certification needed
non organic eggs
- free range (1)
- barn (2)
- caged (3)
how is egg traceability constructed
farming method country of origin famr id registration mark of provnice code of urban district
what happens to wasted/damaged eggs
- removed if cracked and sold as pet food
- if fissured; pasteruized into liquid egg/powder for resturant/industrial use
