U6 Flashcards
proteins as structural components
skin, bones, tendons, muscles
catalytic agents
enzymes
regulating agents
hormones
immune agents
antigens and antibodeis
carriers
myoglobin and hemoglobin - O2 and CO2
nutritional role of proteins
provide AA and N
functions of protiens in food
water binding - texture emulsifiers gel forming coagulating dough forming palatability
what is palatablity
taste, texture, food quality
what protein in bread makes it palatable
gluten
what forms when milk coagulates. what products does this make
a curd. cheese, yogurt, sour cream
what forms when soy proteins coagulates. what product does this make
curd. tofu
what product is protein emulsification important for
sausages
endogenous enzymes
detrimental catalytic behavior in proteins - autolytic
exogenous enzymes
supplied by microbes in food
examples of beneficial catalytic behavior
proteases - tenderize meat
lipases - flavor development
amylases - form corn syrup.sugar products
example of a flavor potentiator
MSG - monosodium glutamate
examples of protein sources other than milk, eggs, and meat
rapeseed, beans, peas, leaves, microbes
what methods make meat analogs from soybean protein
texturization using extrusion
how many amino acids
20
what is the alpha carbon
connected to both NH2 and COOH groups
when is the AA protonated
low pH
when is the AA deprotonated
high pH
what is a zwitterion
COO- and NH3+. net charge zero
when does the zwitterion occur
isoelectric point
formula for isoelectric point
pI = (pk1 + pk2)/2
amino acids have attributes of a … (since the neutral form is still charged
salt
what properties do AA have that are similar to a salt
- crystalline strucutre
- wate soluble
- decompose at high temperatuers
- amphoteric - acid and bases
what occurs due to AA having 4 different substituents
optical isomerism and ability to rotate plant-polarized light. not superimposable
D or L?
both occur - racemic mixtures. but only L can form proteins
what is on the right for D and on the left for L
hyrgogen of alpha carbon
7 categories of amino acids
- aliphatic
- hydroxyl
- carboxyl
- base
- aromatic
- sulfur-containing
- imino
5 types of aliphatic AAs
glycine, alanine, valine, leucine, isoleucine
defining feature of aliphatic AA
hydrophobic