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F & F > Topic 3B > Flashcards

Topic 3B Flashcards

1
Q

what are the roles of PRO in food?

A 
water binding
 gel formation
 thickening
 emulsion
 foam formation 
Maillard rxn
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2
Q

what elements do PROs contain?

A 
C
H
O
N
S
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3
Q

how many AAs are there?

A

20

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4
Q

how many AAs are essential?

A

9

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5
Q

how many AA are conditionally essential?

A

1

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6
Q

how do AAs differ from among each other?

A

side chain

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7
Q

What is unique about a PRO?

A

AA sequence

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8
Q

the balance of AAs in a PRO determines what about its quality?

A

biological value

nutritional quality

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9
Q

what does it mean when a PRO has a high biological value?

A

complete PRO contain adequate amounts of essential AAs

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10
Q

complete PRO

A

contains all essential AAs

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11
Q

what foods contain PROs of high biological value?

A

animal products (ex: milk, eggs, cheese, meat & poultry)

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12
Q

how does a vegan lifestyle acquire a complete PRO source?

A

combination of diff plant PROs

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13
Q

primary structure

A

series of AAs

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14
Q

what determine the primary structure of a PRO?

A

genetics

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15
Q

secondary structure

A

side chains of AA interact with one another in the PRO molecule

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16
Q

tertiary structure

A

alpha helices & beta sheets interact with one another

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17
Q

what structure creates the 3D shape of the PRO?

A

tertiary

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18
Q

quaternary structure

A

multimeric PROs

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19
Q

what type of envr will cause denaturation of a PRO?

A

acidic

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20
Q

PRO shape can be:

A

globular

fibrous

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21
Q

buffering

A

resist change in pH

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22
Q

amphoteric

A

same molecule can take & donate protons in nature

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23
Q

PROs are more soluble at what pH? & why?

A

PROs are more soluble at alkaline pH b/c there are more net OH- ions & thus more interactions with water (H-bonds) remain dissolved in water

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24
Q

what groups on the PROs accept & donate H+?

A

amine = accept

carboxyl = donate H+

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25
Q

what is an ex of PRO buffering in humans?

A

blood carrying various substances altering the pH which could be harmful

the blood buffers the pH

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26
Q

denaturation

A

interactions b/w side chains have changed thus, causing the PRO to acquire a new shape

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27
Q

what structures are disrupted during the denaturation of a PRO?

A

tertiary & quaternary

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28
Q

what causes denaturation?

A

change in the envr –> acids, alkalis, alcohol, heat, heavy metals (ex: Hg), UV radiation

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29
Q

how does denaturation affect the solubility of PROs?

A

reduces, form aggregations

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30
Q

when is denaturation desirable? & how is this accomplished?

A

digestion & by gastric acid containing HCl, causes the side chains to open up & enables enzymes to break them down

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31
Q

when is denaturation undesirable?

A

transport of harmful materials in the blood

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32
Q

foaming & how does this happen?

A

PROs form films around air bubbles

films have repulsive interactions & don’t let the air bubble coalesce stabilizing the foams

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33
Q

PRO films are line with what kind of charge in foaming?

A

negative

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34
Q

gelation

A

PROs can form a gel matrix balancing PRO-PRO interactions & PRO-solvent (water) interactions

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35
Q

water holding capacity

A

the amount of water it can bind to without the water leaking away from it

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36
Q

what factors affect the water holding capacity of a PRO?

A

pH

salt

temp

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37
Q

when does a PRO have the least water holding capacity?

A

isoelectric pH

PRO is compact & not interacting with PRO molecules (insoluble)

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38
Q

isoelectric pH

A

pH where the PRO has a net charge of 0

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39
Q

what causes the increase in WHC?

A

addition of salt

& increase in temp up to a certain point in gel-forming PROs

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40
Q

how does an isoelectric pH affect a PRO’s solubility?

A

insoluble

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41
Q

how does a pH above the isoelectric pH affect a PRO’s charge? how does this affect solubility?

A

net negative charge

increases

42
Q

how does a pH below the isoelectric pH affect a PRO’s charge? & how does this affect solubility?

A

net positive charge

increases

43
Q

emulsification

A

ability to keep oil & water mixed

44
Q

what type of PROs are good emulsifiers?

A

PROs with both hydrophobic & hydrophilic properties

45
Q

what is the pH of milk PRO?

A

6.6

46
Q

what are the PROs included in milk PRO?

A

casein alpha, beta & kappa

47
Q

kappa

A

keeps alpha & beta-casein from precipitating

48
Q

what causes alpha & beta to precipitate?

A

pH change causing casein to become non-functional

49
Q

what are the whey PROs in milk?

A

Lactoalbumin, Lactoglobulin, lactoferrin, lysozyme, lactoperoxidase

50
Q

what are 2 high PRO products made from milk?

A

whey PRO isolate

whey PRO concentrate

51
Q

whey concentrate has more ____ than whey isolate

A

impurities

52
Q

what causes whey PROs to denature?

A

heat ONLY

53
Q

what are the 2 major parts of an egg?

A

egg white

egg yolk

54
Q

older the egg is, the ____ the egg white

A

thinner

55
Q

what decreases an eggs foaming capacity?

A

age

56
Q

what part of the egg is nutritious?

A

yolk

57
Q

how is the quality of eggs determined?

A

candling

haugh unit

58
Q

candling

A

a light enables seeing in the egg where they look for cracks & air cell size

59
Q

haugh unit

A

higher the unit better the quality egg

test buoyancy –> older the egg is, the larger its air cell & the more buoyant the egg

60
Q

what is the major PRO of the egg called? & what characteristic does it have?

A

ovalbumin

high foaming capacity

61
Q

what PROs are found in egg yolk?

A

HDL

LDL

62
Q

what are the functional characteristics of an egg?

A

emulsification

foaming

coagulation

63
Q

emulsification in eggs & when is this used?

A

lipoproteins & phospholipids present in the egg yolk help to keep fat dispersed in water

mayonnaise

64
Q

foaming in eggs

A

PROs in the egg white have a high capacity to form strong PRO films that surrounds air bubbles to produce stable foams

65
Q

coagulation in eggs

A

egg white PROs can set & form a gel during heating

denature easily at high temps

66
Q

red meat eaten in Canada mainly comes from:

A

cattle

pigs

chicken

67
Q

animal flesh consists of:

A

muscle tissue or fibres

connective tissue

fatty (adipose) tissue

68
Q

muscle cells are comprised of:

A

water

PROs

minerals

Vitamins (especially B12)

myoglobin

fat

69
Q

connective tissue PROs:

A

collagen

elastin

70
Q

collagen & what does it form? & what effect does it have when cooked?

A

major PRO in the connective tissue in & around the muscle fibres & tendons is mostly collagen

forms a gel

becomes soft & soluble when cooked

71
Q

collagen solubility

A

water soluble

72
Q

elastin & what effect does it have when cooked?

A

the ligaments which join 2 bones together are mostly made up of elastin (present in tendons & ligaments)

remains tough even when cooked

(yellow colour)

73
Q

muscle fibers are composed of what PROs:

A

actin & myosin

74
Q

muscle fiber length varies due to:

A

Length of fibres varies
Depending on location of muscles in body
Some muscles will be used more than others (ex: legs vs. ribs on cows)

Type of animal
Ex: fish have smaller muscle fibers

Age of animal (more collagen will be deposited)

75
Q

fine muscle fibres & what happens when cooked?

A

tend to come from the muscles of young animals or in older animals from the muscles which do the least work

contain little collagen & are tender even when cooking

76
Q

thick muscle fibres & how does it need to be cooked?

A

tend to be from older animals & also muscles which do the most ‘work’ (ex: neck & skin)

Meat is tougher & needs long, slow cooking with moisture to make it tender (ex: casserole)

77
Q

what are 2 methods of lowering the pH of meat? & why do you want to do this?

A

make the meat more tender

add acid = increase water holding capacity (marinate)

mechanical pounding, break down starch –> tenderization

78
Q

visible fat

A

found in meat underneath the skin, cover fat (subcutaneous fat) & b/w the muscles (intermuscular fat)

seen with the eyes
creamy white colour

79
Q

invisible fat

A

small amount of fat is found in connective tissue surrounding the bundles of muscle fibres

not obvious to the eye

80
Q

removal of what type of fat affects the tenderness of meat? & what is the result?

A

invisible fat

causes it to be dry

81
Q

what causes the colour of meat?

A

myoglobin & hemoglobin (varries with the types of muscle)

82
Q

colour diffs in meat are due to:

A

mainly the metabolism of the species & function of the muscle

(also age & exercise)

83
Q

darker meat comes from what kind of muslces?

A

muscles that have been used a lot more & are older

84
Q

oxymyoglobin

A

myoglobin bound with oxygen

85
Q

metmyoglobin

A

oxymyoglobin oxidized

86
Q

how does oxidation affect the colour of meat?

A

darker = more oxidized

87
Q

why are nitrides (antioxidants) added to meat?

A

prevent browning & growth of microbes

88
Q

why is salt added to meat?

A

prevents growth of microbes & increases water holding capacity

89
Q

what are the principle PROs in wheat?

A

gliadin & glutelin

90
Q

gluten

A

complex formed form gliands & glutelins following hydration (water) & mixing of wheat flour

gliadin + glutelin = gluten

91
Q

why are water & mixing important in the formation of gluten?.

A

triggers the formation of disulfide bonds b/w glutelin

mixing increases the rate of disulfide bond formation

92
Q

hydrated gluten provides what type of structure? & what characteristics does it provide to the wheat flour?

A

3-D viscoelastic network

valued dough & bread making characteristics

93
Q

what does gluten prevent from escaping?

A

CO2

94
Q

gliadin ___b/w ___ molecules

A

floats

glutelin

95
Q

what property does gliadin provide?

A

viscosity

96
Q

what property does glutelin provide?

A

elastic property

97
Q

pulse & oilseed storage PROs contain very little of what PROS & what is their main PROs?

A

gliadin & glutelin

majority of PROs are albumin & globulins

98
Q

single celled PROS come from:

A

yeasts, bacteria & fungi

99
Q

mycoPRO

A

PRO from a fungus

consumption from F. venenatum has been approved

100
Q

mycoPRO supplies:

A

50% PRO

13% lipids

25% fibre

(no cholesterol)

101
Q

what is the trade name of myco PRO?

A

Quorn

102
Q

food use of mycoPROs:

A

Muscle fiber replacer in the manufacture of simulated meats like vegetarian burgers

Fat replacer

Cereal replacer in the manufacture of breakfast cereals

F & F (8 decks)

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