Proteins VII Flashcards
The protein level of soy protein is typically ____%, and the lipid level is usually ____%
45%
20%
In soy protein, an increase of ___% in protein content is accompanied by a decrease of ___% in oil
1
0.5
In soy protein, oil and protein are (positively/negatively) correlated
negatively
The seed composition of soybeans is ___% protein, ___% fat, ___% carbohydrates, ___% ash
40
20
35
5
The main portion of the soybean is the _______
cotyledon
The portion of the soybean that contains mostly carbohydrates is the _____
hull
The portion of the soybean that contains the most lipids is the _____
cotyledon
The _____ and _____ portions of the soybean contain high levels of protein
cotyledon
hypocotyl
______ is equivalent to meat and eggs in terms of protein composition
Soy protein
The main content of protein in soy is found in storage sites called ________ or __________, which are subcellular structures that range in diameter from 2 to 20 um.
protein bodies
aleuronic grains
The ________ have been reported to contain approximately 10 % nitrogen, 0.8 % phosphorus, 8.5 % sugar, 7 % ash, 0.5 % RNA, 4.5 % lipids and 2 % phospholipids.
protein bodies
________ in soybeans are close to 75% proteins
Protein bodies
Apart from proteins (80%), protein bodies in soybeans contain ______________ (20%)
biologically active proteins, such as enzymes, enzyme inhibitors, and lectin
The soybean storage proteins were extracted and characterized for the first time by ______ & ______ in 1898, and they named the extracted protein ______.
Osborne
Campbell
glycinin
The simplest criterion used for the characterization of soybean proteins is their ___________.
solubility in various media
As in all legumes, the bulk of soybean proteins are _______, characterized by their solubility in _____ solutions.
globulins
salt
The solubility of soybean proteins in water is (affected/unaffected) by the pH
strongly affected
Close to 80 % of the protein in raw seeds or unheated meal can be extracted at _____ or ______ pH.
neutral
alkaline
As the (acidity/alkalinity) is increase, solubility drops rapidly and a minimum is observed at pH 4.2 to 4.6
acidity
What is the isoelectric region of soybean proteins as a whole?
4.2 to 4.6
More precise and detailed fractionation of the proteins can be carried-out by techniques such as ___________, _________, and __________
ultracentrifugation, gel filtration and electrophoresis.
It is custom to characterize soybean protein fractions by their _________
sedimentation constants
__________ made it custom to characterize the soybean protein fractions by their sedimentation constants
W. Wolff
These proteins are (homogeneous/heterogeneous) and when ultracentrifuged at pH 7.6 and 0.5 ionic strength, the fractions __S, __S, __S, and __S were given
2
7
11
15
The numerical coefficient is the characteristic sedimentation constant in water at ____oC.
20
The __S and __S fractions constitute about 70 % of the total protein in soybeans.
11S
7S
The ratio 11S/7S is a varietal characteristic and may vary from ____ to ____
0.5
3
__S fraction is composed of a-conglycinin and low molecular weight polypeptides
2
The components of __S also comprise the soybean trypsin inhibitors
2
__S is highly heterogeneous
7
The principal component of __S is B-conglycinin, a sugar containing globulin
7
__S also contains gamma-conglycinin, the enzymes (B-amylase and lipoxygenase), and hemagglutinins
7
__S is glycinin, the principal protein of soybeans with a built of 12 subunits
11
__S is a dimer of glycinin
15
_________ is the enzyme responsible for rancidity in soybean oil by oxidation of linoleic acid, the major constituent of soybean oil. Also leading to the beany smell and flavor.
Lipoxygenase
The _______ is obtained by comparing the essential amino acid composition to that of a standard reference protein
chemical score
The chemical score uses an _______ as a standard reference protein
egg
In soybean, the limiting amino acids are the ones containing ______, which are ______ and _______
sulfur
methionine
cystine
The chemical score of soybean protein is ____%
70
Soybean is exceptionally rich in _______ and can serve as a valuable supplement to cereal foods
lysine
Chemical score alone is not a satisfactory measure of protein quality since it does not account for _________ and the _____________________
protein digestibility
biological availability of the amino acids.
What are the 3 predictors that assess nutritional performance of a protein under certain experimental conditions (in rats)?
- Biological value (BV)
- Protein efficiency ratio (PER)
- Net protein utilization (NPU)
Attempts to develop, genetically, soybean varieties with a higher content of sulphur containing amino acids have (been/not been) successful.
not been
Soybeans, as all seeds, contain the enzyme systems necessary for ________.
germination
Technologically, the most important enzyme in soybeans is ___________, also known as ___________.
lipoxygenase
lipoxydase
________ catalyzes the oxidation of polyunsaturated fatty acids by molecular oxygen,
Lipoxygenase
__________ activity is also the reason for the occasional use of small amounts of unheated soybean flour as a bleaching (carotenoid oxidizing) agent in wheat flour.
Lipoxygenase
The enzyme ______ has served as an indicator for the adequacy of the heat treatment given to soybean meal
urease
Residual ________ activity is still sometimes used as an evidence of insufficient heat treatment.
urease
Protease inhibiting proteins are present in soybeans as ______ inhibitors
trypsin
The two types of soybean trypsin inhibitors are the _______ inhibitor (large), and the ________ inhibitor (small)
Kunitz
Bowman-Birk
It has been known for a long time that ___________ or ______________ will impair growth when fed to young rats or chicks, which is completely eliminated when the soybean is properly heated
raw soybeans
unheated soybean meal
The presence of __________ in the diet is responsible for the suppression of growth.
trypsin inhibitors
The ingestion of ______________ can result in increased pancreatic secretion and hypertrophy of the pancrease
trypsin inhibitors
Increased secretion of enzymes into the digestive tube represents an internal (gain/loss) of protein.
loss
The proteins excreted by the pancreas are particularly rich in ______ containing amino acids, the internal loss of protein could be specially important if the diet is marginal in _________/________
sulfur
methionine/cystine
True or false: trypsin inhibitors are toxic to humans.
False; there is no direct evidence, BUT it is custom to remove the trypsin inhibitors
The ______, formerly known as __________,are proteins which possess the ability to agglutinate red blood cells.
lectins
hemagglutinins
________ are widely distributed in plants and some, such as the castor bean _______, are highly toxic.
Lectins
lectin recin
The ______ found in soybeans has no observable effect and is easily inactivated by heat
lectin
Functional properties are related to the ______ structure, and the ______ and _______ structures
primary
secondary
tertiary
Soybean protein products with unique functional properties are available and constitute important tools in the formulation of the so-called _______________
fabricated foods
Soybean oil is obtained by ___________
solvent (hexane) extraction
________ used as cooking oil, but also used in the chemical industry as starting material for bio-diesel,inks,plasticizers,crayons,paints and even candles.
Soybean oil
Soy meal is obtained from grounded flakes after ________
oil extraction
_______ is used for feed (cattle, swine, poultry)
Soy meal
_______ refers to defatted soybeans where special care was taken during solvent removal to minimize denaturation of the protein
Soy flours
_______ are the starting material for protein enriched soy products
Soy flours
______ constitute 65%-85% protein content
Soy protein concentrate (SPC)
______ are usually manufactured by using alcohol to remove the soluble carbohydrates from the de-oiled soy flakes, resulting in a protein with (high/low) solubility incapable to ____ or ________
SPC
low
gel
emulsify fat
Traditional alcohol-washed _________ are used for protein fortification of foods as well as in the production of textured soy concentrates.
soy concentrates
___________ are produced using minimum heat and homogenization followed by spray drying, or by using a water-wash process at an (acid/base) pH to remove soluble _______, followed by neutralization
Functional soy concentrations
acid
sugars
_______________ hold water, emulsify fat and form a gel upon heating; they are widely used in the meat industry and are also efficient for the stabilization of high fat soups and sauces.
Functional soy concentrates
_________ contain 85% or higher of protein
Soy protein isolate (SPI)
______ are bland in flavor, light in color, and have a number of functional properties such as gelation,viscosity,emulsification,water holding capacity,and even some foaming and whipping ability.
Soy protein isolates (SPI)
What are the four cereals?
Wheat, corn, barley, rice
Cereals all contain ______ as their major component along with 6-20% _______
starch
protein
Wheat proteins are often isolated as a byproduct of ______ manufacture
starch
The protein fraction of starch is termed _____
gluten
______ is used to produce protein hydrolysates and is used as an additive to strengthen soft wheats
Gluten
________ is the ground _______ of the wheat kernel made up of _____ granules held within a ____ matrix
Wheat flour
endosperm
starch
protein
_______ are unique in being capable of providing loaf volume
Wheat proteins
