9 protein intro Flashcards

1
Q

what are proteins?

A

macromolecules comprised of amino acids bound by peptide bonds

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2
Q

what’s the term for: providing a specific useful property or function in a food product

A

[protein] functionality

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3
Q

what are some useful properties targeted in protein functionality?

A
  • water binding capacity
  • emulsification capactiy
  • gel forming ability
  • coagulating properties
  • dough forming abilities
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4
Q

soybeans form a curd called

A

tofu

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5
Q

______ activity can be both beneficial and detrimental

A

enzymatic

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6
Q

name some examples of enzyme

A
  • protease - meat tenderizer
  • lipase - flavor developer
  • amylase - syrup/sugar manufacturing
  • glucose oxidase - remove headspace of packaging
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7
Q

what’s MSG?

A

monosodium glutamate - a flavor potentiator.

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8
Q

what are some currently uncommon sources of protein in our culture?

A
  • rapeseed
  • beans
  • peas
  • leaves
  • microorganisms
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9
Q

pros and cons of using plant proteins?

A

pros: more abundant, cheaper
cons: lesser protein quality

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10
Q

what is surimi?

A

imitation crab/scallop meat made from pollock

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11
Q

what are the components of an amino acid?

A

amine (NH2), carboxylic acid (COOH), and side chain (R) groups attached to an alpha carbon

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12
Q

at a low pH, an amino acid is

A

protonated (COOH/NH3+)

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13
Q

at neutral pH, an amino acid is

A

zwitterion (COO-/NH3+); net neutral charge

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14
Q

at a high pH, an amino acid is

A

unprotonated; net negative (COO-/NH2)

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15
Q

what does the pKa tell you?

A

when a H will pop on or off

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16
Q

a substance that can act as both an acid and a base is considered:

A

amphoteric

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17
Q

1) a protein in its neutral form have the attributes of a:

2) some of these attributes include

A

1) salt

2) crystalline structure, water soluble, decomposition at high temps

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18
Q

what is the only amino acid that is achiral?

A

glycine (R=H)

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19
Q

what are optical isomers?

A

mirror images of a compound that can’t be superimposed

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20
Q

asymmetry give a molecule the ability to rotate _____ ______ ______ in opposite directions

A

plane polarized light

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21
Q

what compound is used as a reference for determining configuration?

A

glyceraldehyde

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22
Q

it glyceraldehyde has its OH group on the right, what form does it have? what about left?

A

D or dextro; L or levo

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23
Q

what group do we look at when determining an amino acid’s form?

A

NH3 (amine) group; if it’s on the left it’s L, if it’s on the right it’s D

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24
Q

naturally, our amino acids come in what form?

A

L

25
Q

what are the 7 categories of amino acids?

A

1) aliphatic side chain
2) hydroxy side chain
3) carboxylic side chain
4) basic side chain
5) aromatic side chain
6) sulfur-containing
7) imino acids

26
Q

what are the aliphatic amino acids?

A

glycine, alanine, valine, isoleucine, leucine

27
Q

what are some attributes of the aliphatic amino acids?

A
  • relatively unreactive

- as chain length increases so does hydrophobicity

28
Q

is glycine hydrophobic?

A

hell naw

29
Q

what are the hydroxy side chain amino acids?

A

Serine (Ser), Threonine (Thr), Tyrosine (Tyr)

30
Q

what are some attributes of the hydroxy side chain amino acids?

A
  • OH can form ester linkage with a phosphate group
  • OH enables hydrogen bonding
  • OH is a very reactive moiety
31
Q

true or false: casein is heat stable

A

true

32
Q

O-glycosidic linkages are associated with what functional group?

A

OH

33
Q

what are the carboxylic amino acids?

A

aspartic acid, glutamic acid and their amides, asparagine and glutamine

34
Q

what are some attributes of the carboxyl amino acids?

A
  • COOH is a very reactive group
  • at pH 7 they are negatively charged (polar)
  • tend to have LOW isoelectric points
  • play a role in non-enzymatic browning reactions
  • water soluble
35
Q

what serves as an attacking point for reducing sugars?

A

amide group

36
Q

N-glycosidic linkages are associated with what functional group?

A

amide

37
Q

what are the basic side chain amino acids?

A

lysine, histidine, arginine

38
Q

what are some attributes of amino acids with basic side chains?

A
  • high isoelectric points
39
Q

how many amide groups does lysine have?

A

2

40
Q

arginine has a _____ group

A

guanadino

41
Q

histidine has a _____ group

A

imidazole group

42
Q

when a protein reaches its isoelectric point, this is its point of (highest/lowest) solubility in water

A

lowest

43
Q

what are the aromatic amino acids?

A

phenylalanine, tyrosine, tryptophan

44
Q

what are some attributes of the aromatic amino acids?

A
  • can absorb UV light

- quite hydrophobic

45
Q

what are the sulfur containing amino acids?

A

cysteine, cystine (cysteine’s dimer), and methionine

46
Q

a _____ _____ holds together two cysteine residues

A

disulfide crosslink

47
Q

1) cystein has a:

2) this group is (acidic/basic)

A

1) sulfhydryl group (SH)

2) basic

48
Q

what are the imino acids?

A

proline, hydroxyproline

49
Q

what makes imino acids different?

A

they lack an NH2 group. they have NH instead

50
Q

what are some attributes of imino acids?

A
  • interrupt natural tendency to form alpha helix
  • found in collagen
  • can’t form intramolecular hydrogen bonds
51
Q

what are the essential amino acids?

A

HPVL2IT2

  • histidine
  • phenylalanine
  • valine
  • leucine
  • lysine
  • isoleucine
  • threonine
  • tryptophan
52
Q

what are the conditionally essential amino acids?

A

A2G2PST

  • arginine
  • asparagine
  • glutamine
  • glycine
  • proline
  • serine
  • tyrosine
53
Q

what are the nonessential amino acids?

A
  • Alanine
  • Asparate
  • Glutamate
  • Cysteine (we don’t need cancer)
54
Q

what are used extensively as flavoring agents to provide a meaty/brothy flavor?

A

hydrolysates

55
Q

what is an example of a hydrolysate that’s made from fermented soybeans

A

soy sauce

56
Q

what do sulfur containing amino acids release to provide flavor due to their breakdown while being cooked?

A

H2S - hydrogen sulfide

57
Q

what is responsible for flavors?

A
  • peptides
58
Q

the process of decay or rotting in a body or other organic matter is known as

A

putrefaction

59
Q

what causes odors and off flavors association with putrefaction?

A
  • enzymatic deamination

- decarboxylation of free amino acids by microbial enzymes