Lab - Biological Evaluation of Foods Flashcards
protein type that contains all the essential AAs in amounts that meet what is required by humans to prevent deficiency
complete protein
all animal proteins are complete proteins except __
gelatin
protein type that is too low in one or more of the essential AAs to support human growth and maintenance
incomplete protein
most plant proteins are incomplete proteins except __
soy
Combinations of incomplete proteins that, when
added together, result in a complete protein
complement proteins
Legumes and grains: incomplete protein. But they complement each other
legumes: lysine
grains: methionine
To optimize meal-stimulated protein synthesis in
muscle, there must be full complement of essential AAs
+ relatively high content of this AA
leucine
full complement of essential AAs
+ relatively high content of this AA = maximally stimulate what pathway?
mammalian
target of rapamycin pathway
Enumerate two aspects of evaluating protein quality
Amino acid profile (compared to “ideal” pattern)
Digestibility of the protein
• normally the reference protein is __because it
contains all the essential AAs
egg
Enumerate 3 factors that can limit digestibility of plant protein
cell wall barrier (wall can’t be digested)
lipase
trypsin
current “gold” standard by FAO/WHO for assessing
protein quality; incorporates digestibility as a factor in quality of proteins
Protein Digestibility Corrected Amino Acid Score
Complete proteins can often have PDCAAS values of
__
≥ 1.00
Which is false?
A.For PDCAAS, values above 1.0 are truncated.
B.PDCAAS accounts for relative AA differences among
proteins with PDCAAS for 1.0.
C.PDCAAS does not take into consideration protein ileal digestibility.
B
does not account dapat
false about Protein Efficiency Ratio
A.Assesses weight gain of growing animals on a
particular protein source (eg rats, chicks)
B.Suitable as an index for human consumption
C.Weight gain is a function of level of protein and
kind of protein
B
not suitable dapat
what percent of protein level – maximum growth? for PER
10%
3 extraneous factors that may affect PER. Enumerate.
Season
Sensitivity of animals to care
Changes in temperature
2 disadvantages of PER. Enumerate.
Weight gain is not constant with protein level
No room for allowance for maintenenance
Which is false?
A.Nitrogen balance gives specific information on flux of protein/AA pool within tissues/organs.
B.Carbohydrate and fat are protein-sparing.
A
does not give dapat
What is biologic value of protein quality?
Measures how much nitrogen is retained in the body
Biologic value of protein quality is not meaningful for individual components of mixed diets. Why?
since limiting AAs can
differ between sources
collective term for urinary and fecal nitrogen
losses from the protein diet
metabolic nitrogen
collective term for nitrogen losses from the
protein-free diet
endogenous nitrogen
negative nitrogen balance indicates ___
protein loss
