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FDSC300 > 12-CHO > Flashcards

12-CHO Flashcards

1
Q

what are the 4 physical methods?

A

Refractometry
Hydrometery
Pycnometery
Polarimetry

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2
Q

what are the 5 methods of analysis CHO?

A 
chemical
physical
enzymatic
instrumental
immunoassay
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3
Q

what are the 3 methods of chemical?

A

cholorimetric
titration
gravimetric

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4
Q

what are the 4 methods of instrumental?

A

chromatography
NMP
electrophoresis
IR

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5
Q

what are the 3 methods of colorimetric methods?

A

phenol sulfuric acid
anthrone
somogyi-nelson

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6
Q

what is the method of titration?

A

lane-eynon

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7
Q

what is the method of gravimetric?

A

munson-walk

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8
Q

what does Refractometry based on?

A

refractive index: The absolute refractive index of a medium is the ratio of the speed of light in vacuum relative to the speed in the medium.

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9
Q

The absolute refractive index of a medium is the ratio of ?

A

the speed of light in vacuum relative to the speed in the medium.

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10
Q

When a beam of light is passed from one medium to another and the ____ of the two differs, then the beam of light is ____or refracted.

A

density

bent

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11
Q

what is the principle of refractometry?

A

snell’s law

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12
Q

what does snell’s law state?

A

Snell’s law states that the ratio of the sines of the angles of incidence and refraction is equivalent to the ratio of phase velocities in the two media
n1 * sinα = n2* sin β
n1= refractive index of medium 1
n2= refractive index of medium 2

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13
Q

Refractive index is a characteristic property of a _____?

A

liquid

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14
Q

what does Refractive index of a solution related to ?

A

the density of the solution.

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15
Q

what does Refractive index of a solution depend on ?

A

the concentration of the solution, temperature and wavelength.

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16
Q

the refractive index of pure water is?

A

η20 = 1.33299

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17
Q

what does additional sugar in water change?

A

the density of water, leads to change refractive index (η)

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18
Q

what does the RI of a solution increase with concentration been used in?

A

analysis total soluble solids of CHO-based food such as sugar syrup, fruit product, tomato products.

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19
Q

where can refractometer used in?

A

in a liquid processing line to monitor the Brix of products such as carbonated soft drinks, dissolved solids in orange juice, and % of solids in milk.

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20
Q

what can refractometer monitor?

A

the Brix of product

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21
Q

give ex of the brix of product

A

carbonated soft drinks
dissolved solids in orange juice
% solid in milk

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22
Q

what are 3 types of refractometer?

A

abbe–handheld–benchtop

digital

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23
Q

what is the adv of benchtop abbe refractometer? disadv

A

wider measurement range
more precision
less portability携带性

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24
Q

what is the principle of hydrometry?

A

Is based on Archimedes’s principle, which states that a solid suspended in a liquid will buoyed by a force equal to the weight of the liquid displaced.
In other words, an object displaces a weight of liquid equal to its own weight.

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25
Q

what does hydrometry based on?

A

Based on displacement of a liquid by a floating body.

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26
Q

hydrometry: wt of an object=?

A

wt of the displaced liquid

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27
Q

hydrometry: wt=__x___

A

volume x density

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28
Q

V X D object=?

A

V X D displaced liquid

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29
Q

what does hydrometer measure?

A

specific gravity

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30
Q

specific gravity= ___/____

A

density of liquid/ density of water

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31
Q

what does lactometer used to determine?

A

the density of milk

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32
Q

what does baume hydrometer used to determine?

A

the density of salt solution

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33
Q

what does alcoholometer used to determine?

A

the alcohol content of beverage

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34
Q

what does brix hydrometer (saccharometer) used to determine?

A

sugar solution e.g. fruit juice, syrup

– sucrose content in solution

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35
Q

to measure the density of milk, which hydrometer can be used?

A

lactometer

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36
Q

to measure the sucrose content in solution, which hydrometer can be used?

A

saccharometer/ brix hydrometer

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37
Q

to measure the density of salt solution, which hydrometer can be used?

A

baume hydrometer

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38
Q

to measure the alcohol content of beverage, which hydrometer can be used?

A

alcoholometer

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39
Q

what is Brix?

A

a percentage of sucrose by wt. in a solution.

=% sucrose

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40
Q

what does one degree Brix equal?

A

1g sucrose in 100g solution

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41
Q

what does Brix reporesent?

A

the strength of the solution as percentage by mass.

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42
Q

what does 20O brix equal?

A

20% sucrose

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43
Q

what does pycnometery based on?

A

measuring specific gravity, but not directly

44
Q

specific gravity= __/___=____/_____

A

specific gravity= density of liquid/ density of water= W/V of liquid/ W/V of water

45
Q

what are the steps of pycnometery?

A

w1-empty pycnometer
w2-fill it with water
w3-fill it with liquid
w3-w1/w2-w1=SG specific gravity

46
Q

what kind of molecue have the ability to rotate plane polarized light?

A

molecules contain an asymmetric carbon atome (chiral molecules)

47
Q

what ability does optical active substance have?

A

rotate the polarized light.

48
Q

why are sugar optical active?

A

they are chiral

49
Q

is sugar optical active or not?

A

optical active

50
Q

how many asymmetric carbon atoms does glu have? and their mirror images can/cannot superimpose!!

A

Glucose has four asymmetric carbon atoms and their mirror images cannot superimpose!!

51
Q

polarimeter is used to measure?

A

optical activity

52
Q

light source–> ______—>sample—>________

A

light source–>fixed polarizer—>sample—>moveable polarizer

53
Q

what does polarizer absorb?

A

one component of the polarization but not the other

54
Q

the input is natural light, what is the output?

A

polarized light

55
Q

what are the 3 type of polarized light?

A

linear, circular, elliptical

56
Q

how does the polarized work? to get input natural light, output polarized light?

A

dichroism
reflection
scattering

57
Q

what is dextrorotory?

A

when the plane of polarized light is rotated in a clockwise direction when viewed through a polarimeter.
(+) or (d) do not confuse with D

58
Q

what is levorotatory?

A

when the plane of polarized light is rotated in a counter-clockwise
direction when viewed through a polarimeter.
(-) or (l) do not confuse with L

59
Q

what does (+) or (d) represent?

A

dextrorotatory

60
Q

what does (-) or (l) represent?

A

levorotatory

61
Q

what is specific rotation?

A

the angle of rotation of plane polarized light by a 1.00 gram per cm-3
sample in a 1 dm tube.

62
Q

write the equation of specific rotation

A

[α ]T,D (T= temperature, D = sodium lamp).

63
Q

what is rotation related to?

A

number of molecules in the solution, which is concentration in g substance/ 1 cc solution.

64
Q

[α]D=?

A

α/I*d

65
Q

α/I*d, what is each one represent?

A

α=observed rotation
I=length dm
d=concentration g/cc

66
Q

[α ] 20D (+)-alanine =

A

+8.5

67
Q

[α ] 20D (-)-lactic acid =

A

-3.8

68
Q

[α ] 20D (+)-glucose =

A

+52.5

69
Q

[α ] 20D (+)-sucrose =

A

+66.5

70
Q

[α ] 20D (-)-fructose =

A

-93

71
Q

what method can use to specific analysis of mono-oligosaccharide?

A
  1. enzymatic method

2. chromatographic method

72
Q

what does carrez treatment used to?

A

Breaks emulsions, precipitates proteins, and absorbs colors from food products prior to enzymatic determination of carbohydrates

73
Q

enzymatic method use ____ treatment to prepare sample?

A

carrez

74
Q

write down the steps to prepare sample in enzymatic method

A 
add potassium ferrocyanide
add zinc sulfate ZnSO4
add sodium hydroxide
filtration suspension
use clear suspension for enzyme-catalyzed assay
75
Q

which 3 reagent need to add for prepare enzyme sample?

A

potassium ferrocyanide
zinc sulfate
sodium hydroxide

76
Q

ex of enzymatic methods

A

GOPOD method

glucose oxidase/ peroxidase/dye

77
Q

what does glucose oxidase do?

A

oxidizes d-glucose quantitatively to d-glucono-

1,5-lactone and hydrogen peroxide

78
Q

how is D-glu measured?

A

from H2O2 generated using peroxidase that turns a colorless compound (a leuco dye) to a colored
compound
H2O2+ colorless dye—(with peroxidase)–> colored compound +2H2O

79
Q

how is the colored compound measure?

A

spectrophotometrically

80
Q

give an ex of peroxidase turns color

A

dye 4 amino-antipyrene producing red quinoeimine in presence of H2O2 and peroxidase)

81
Q

another ex of enzymatic method can treat

A

starch

82
Q

is enzyme resistant starch detected?

A

no

83
Q

Purity of enzyme used is _____

A

critical

84
Q

Presence of cellulases, invertase, sucrase, β-glucanase releae D-glucose from other than starch (false ____ value)

A

high

85
Q

what can catalase do? cause?

A

destroy the hydrogen peroxide, false low value

86
Q

write down treat the starch steps

A
  1. starch gelatinize in hot DMSO
  2. get starch solution, then digest with a-amylase, which is 1,4-linked a-d-glucopyranosyl unit
  3. get linear and branched fragment of amylose and amylopectin
  4. digest with glocoamylase get D-glucose
  5. add GOPOD reagent to see the color
87
Q

which linkage is a-amylase?

A

1,4-linked a-d glucopyranosyl unit

88
Q

D-glu add ______ to see the color

A

GOPOD reagent

89
Q

what are the cons of enzymatic methods

A
  1. need clear solution
  2. optimum condition- buffer, ph ,temp
  3. possible interference from other components
90
Q

what are the pros of enzymatic methods?

A
  1. higher specificity
  2. don’t need high purity of the sample
  3. low detection limits
  4. don’t need expensive equipment
  5. easy automated
  6. commercially available kits
91
Q

do enzyme method need high purity sample?

A

no

92
Q

do enzyme method need clear solution?

A

yes

93
Q

do enzyme method need optimum condition- buffer, ph ,temp?

A

yes

94
Q

what is chromatography used for?

A

specific carbohydrate analysis

95
Q

give 2 ex of chromatography

A

HPLC high performance liquid-c

GC gas-c

96
Q

describe GC, how GC analysis cho?

A

Qualitative and quantitative analysis of carbohydrates

97
Q

write down the 2 detector?

A

FID-flame ionization detector

MS-mass spectrometric

98
Q

Sugars must be converted into _________

Reduction of _____groups to _______groups and conversion of the ______ (alditol) into ________ esters

A
  • -volatile derivatives
  • -aldehydic groups to primary hydroxyl groups
  • -conversion of the reduced sugars (alditol) into volatile peracetate esters
99
Q

HPLC: can use for what kind of analysis?

A

quantitative-peak integration

qualitative- identify cho

100
Q

HPLC: adv

A
  • relatively faster
  • possibility of wide range of sample concentration
  • high degree of precision and accuracy
101
Q

what can AE-HPLC coupled to an ECD used for?

A

detection and quantification of carbohydrate from complex mixtures

102
Q

Selection of mobile phase, column (usual one as anion exchange (AE)) and detector (pulsed electro chemical detector (ECD)) may depend on?

A

the specific carbohydrate analyzed

103
Q

the specific carbohydrate analyzed can decide?

A

Selection of mobile phase, column (usual one as anion exchange (AE)) and detector (pulsed electro chemical detector (ECD))

104
Q

how to detect and quantify cho from complex mixture?

A

AE-HPLC coupled to an ECD

105
Q

what is HPAEC

A

high performance anion exchange chromatography

106
Q

what is TLC

A

thin layer chromatography

FDSC300 (10 decks)

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