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FDSC300 > 11-CHO > Flashcards

11-CHO Flashcards

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1
Q

The Components included in a “Proximate Analysis” approach are?

A

(1) Moisture
(2) Ash
(3) Protein
(4) Fibre
(5) Fat

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2
Q

____ is generally not included? why?

A

CHO, because it exists in different forms.

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3
Q

how does %cho measured?

A

%CHO= 100- (%H2O+ %Ash+ %Protein+ %Fibre+ %Fat).

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4
Q

N-containing is the?

A

crude protein

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5
Q

ash is organic/inorganic?

A

inorganic

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6
Q

what is the function of digestible cho?

A

metabolic energy

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7
Q

what is the function of non-digestible cho?

A

•bulkiness,body,
viscosity,stability to emulsions
and foams,
• water-holding capacity,
• stability to freezing and thawing,
• browning (including generation of flavors and
aromas),
• textures (from crispness to smooth, soft gels),
• lower water activity and thereby inhibit
microbial growth

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8
Q

according to WHO/FAO, CHO is classified on _____? also known as ____?

A 
molecular size (degree of polymerization (DP))
 Sugars (DP 1–2)
 Oligosaccharides(DP 3–9)
 Polysaccharides (DP >9)
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9
Q

DP1-2

A

sugar

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10
Q

oligosaccharide DP?

A

3-9

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11
Q

polysaccharide DP?

A

> 9

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12
Q

According to international nomenclature rules, Oligosaccharide as carbohydrate
composed of ___ to ___ _____ units
Polysaccharides usually contain ____ to ____ or more _______

A

2-20 sugar units

30-60,000 monosaccharide

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13
Q

give ex of monosaccharides

A

glucose, Fructose, galactose, arabinose and xylose ).

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14
Q

give ex of oligosaccharides

A

e.g disaccharides such as sucrose and lactose, and trisaccharides such as raffinose

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15
Q

what are polysaccharides,, ex.

A

Polysaccharides are polymers of monosaccharides (>10).

  1. 1-Homopolysaccharides (e.g. starch, cellulose, glycogen formed from only glucose).
  2. 2-Heteropolysaccharides (e.g. pectin, hemicellulose and gums).
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16
Q

is arabinose mono, oligo or poly?

A

mono

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17
Q

is raffinose mono, oligo or poly?

A

oilgo, trisaccharides

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18
Q

is xylose mono, oligo or poly?

A

mono

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19
Q

what is homopolysaccharide?

A

formed from only glucose

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20
Q

ex of homopolysaccharide?

A

cellulose, glycogen, starch

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21
Q

ex of heterpolysaccharide?

A

pectin, hemicellulose, gums

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22
Q

Carbohydrates in foods may be present as?

A

1- Unbound molecules
2- physically associated to other molecules (starch,
granules)
3- chemically bound to other molecules (glycolipids,
glycoproteins)

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23
Q

starch is _____ associated to other molecules?

A

physically

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24
Q

glycolipids is _____ associated to other molecules?

A

chemically

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25
glycoprotein is _____ associated to other molecules?
chemically
26
granules is _____ associated to other molecules?
physically
27
why determine food cho?
Nutritional Labeling Detection of Adulteration Food Quality food processing
28
what is food quality?
physicochemical properties of foods such as sweetness, appearance, stability and texture depend on the type and concentration of carbohydrates present.
29
the type and concentration of carbohydrates that are present affect?
- --the efficiency of many food processing operations | - --physicochemical properties of foods such as sweetness, appearance, stability and texture
30
The carbohydrate content of a food can be determined by calculating the _________________have been measured?
calculating the percent remaining after all the other components % Carbohydrates = 100 - ( %H2O+ %protein + %lipid+ %Ash + %Fiber).
31
This method can lead to _________ due to _____________, and so it is better to ________ measure the carbohydrate content for accurate measurements.
erroneous result | experimental error in any of the other methods, directly
32
how does the sample prepared?
1. raw material, dry get water and dehydrated material 2. dehydrated material 1. grind, 2. extracted with 19:1 CHCl3-MeOH, get lipids and lipid-soluble components , residue 3. residue: extract with 80% ethanol get ion exchange, residue 4. ion exchange , get mono and disaccharide
33
list the methods to analysis CHO
1. chemical methods 2. physical 3. enzymatic 4. instrumental methods 5. immunoassays
34
what does chemical methods have?
Colorimetric methods, Titration methods, Gravimetric methods.
35
what does physical methods have?
Polarimetry, Refractometery, | Density
36
what does instrumental methods have?
chromatography NMR electrophoresis IR
37
what does NMR belong to?
instrumental
38
what does polarimetry belong to?
physical
39
what does gravimetric belong to?
chemical
40
what does colorimetric belong to?
chemical
41
what does refractometery belong to?
physical
42
what does chromatography belong to?
instrumental
43
what does electrophoresis belong to?
instrumental
44
what does density belong to?
physical
45
what does titration belong to?
chemical
46
what does IR belong to?
instrumental
47
what does colorimetric methods have?
Phenol-Sulfuric Acid Method, | Anthrone Method, Somogyi-Nelson Method
48
what does titration method have?
lane-enon method
49
what does gravimetric method have?
munson-walker method
50
describe phenol-sulfuric acid method? what does it used for
used for total cho sample have cho, heat add H2SO4, get furan component, condensation with phenol, get colored compounds, yellow-gold color, measure by spectrophotometer at 490nm
51
what does phenol-sulfuric acid belongs to ?
colorimetric, chemical
52
what does lane-enon belongs to ?
titration, chemical
53
what does munson-walker belongs to ?
gravimetric, chemical
54
what does anthrone belongs to ?
colorimetric, chemical
55
what does somogyi-nelson belongs to ?
colorimetric, chemical
56
what is the adv for phenol-sulfuric acid method?
Simple, sensitive, accurate, specific for carbohydrates.
57
what kind of reaction is not involved in phenol sulfuric acid?
stoichiometric reaction
58
the extent of reaction is a function of the ________of the sugar. - If different sugars found in the sample, _______ is used to prepare the standard curve. - _____or any other _______ _______produce a _______ result
the extent of reaction is a function of the structure of the sugar. - If different sugars found in the sample, glucose is used to prepare the standard curve. - Sorbitol or any other sugar alcohol (alditol, polyol, polyhydroxyalcohol) does not produce a positive result
59
what is the basic principle of anthrone method?
Carbohydrates are dehydrated by strong acids to produce (furan component).
60
what does anthrone methods used for?
quantification total cho
61
Furan components react with ______ reagent to yield a _______ color solution. - Absorbance is measured at _____nm. Note: This method measure _______carbohydrates
Furan components react with Anthrone reagent to yield a blue- green color solution. - Absorbance is measured at 620nm. Note: This method measure reducing and non reducing carbohydrates
62
fehling's test is commonly used for _____ sugars.
reducing
63
in fehling's test, what is detected?
the presence of aldehyde
64
how can aldehyde detected in fehling's test
by reduce deep blue solution of copper(II) to a red precipitate of insoluble copper oxide.
65
to prepare fehling's solution, 2 solution are required. Fehling's "A" uses __ g ________ dissolved in _______containing 2 drops of ______ Fehling's "B" uses ___g of ______ and ___g of _____in 100 ml of distilled water.
Fehling's "A" uses 7 g CuSO4.5H2O dissolved in distilled water containing 2 drops of dilute sulfuric acid. Fehling's "B" uses 35g of potassium tartrate and 12g of NaOH in 100 ml of distilled water. A: CuSO4.5H20+water+dilute sulfuric acid B: potassium tartrate+NaOH+water
66
which method quantification of total cho?
anthrone, colorimetric, chemical
67
which method quantification of reducing sugar?
somogyi-nelson, colorimetric, chemical
68
somogyi-nelson method is the improvement on ___ method. For determination of oligo- and polysaccharides, ______are used before the addition of reagent
fehling's | enzymes
69
what is the priciple of somogyi-nelson methods?
aldehyde group of reducing sugar reduces Cu2+-->Cu+ in basic solution.
70
_____ (e.g. fructose) enolize to ____ in basic solution so they are also _____ sugars.
Ketoses aldoses reducing sugars.
71
how is arsenomolydate produced?
ammonium molybdate [(NH4)6Mo7O24] with sodium arsenate (Na2HAsO7)
72
Cu+ reduces the arsenomolybdate to a _____ product
stable blue product
73
Absorbance at ____ nm is read and samples are quantified against a standard curve of _____
Absorbance at 520 nm glucose
74
Somogyi-Nelson Method Steps
1- A solution of Cu2SO4 and NaOH is added to a solution of reducing sugars. 2- The mixture is heated in a boiling water bath. * Reducing sugars reduce Cu (II) to Cu (I). 3- Add an arsenomolybdate complex reagent (arsenomolybdate complex produced from ammonium molybdate [(NH4)6Mo7O24] with sodium arsenate (Na2HAsO7). 4- Cu (I) reduces arsenomolybdate complex; reduction of the arsenomolybdate complex produces a stable blue color solution that is measured spectrophotometrically.
75
lane&eynon are ___ methods?
titration, chemical
76
what is titration methods based on?
-is based on reducing action of carbohydrates toward certain metallic salts.
77
what does reducing sugar in sample do for titration method?
reduce copper sulfate (CuSO4) from Cu(II) to Cu (I) in alkaline tartrate system (Potassium sodium tartrate, KNaC4H4O6) with NaOH.
78
titration method: titrate cho against?
known concentration of CuSO4 in alkaline condition
79
titration method: what is use as indicator?
Methylene blue
80
titration method: what happen when all cuso4 is used up
reducing sugar will reduce MB to form colorless solution
81
what are disadvs of titration method?
- -the results depend on the precise reaction times, temperatures and reagent concentrations used and so these parameters must be carefully controlled. - -it cannot distinguish between different types of reducing sugar. - -it is susceptible to interference from other types of molecules that act as reducing agents..
82
titration method: what determine the precise?
reaction time, temp, reagent concentration
83
what belong to gravimetric method?
Munson & Walker Method
84
describe Munson & Walker Method
Carbohydrates are oxidized in the presence of heat and an excess of copper sulfate in alkaline tartrate under carefully controlled conditions Leads to the formation of a copper oxide precipitate Reducing sugar + Cu2+ + base---> oxidized sugar + CuO2 (precipitate)
85
Munson & Walker Method is what method?
gravimetric method, chemical
86
Munson & Walker Method: what is the amount of precipitate formed directly related to?
the concentration of reducing sugars in the sample
87
Munson & Walker Method: how is the amount of precipitate present determined?
gravimetrically
88
Munson & Walker Method: suffers from the same disadvantages as the _____ method, nevertheless, it is more _____ and ______.
Lane-Eynon method, reproducible and accurate.
89
how to do gravimetrically
by filtration drying weighing
90
what is oxidation?
loss e-
91
what is reduction?
gain e-
92
reducing sugar can____ e-? act as ____agent
give up | reducing agent
93
oxidizing agent will reduced by_____ e-
receive
94
receive e- is ____?____ agent?
reduction, oxidizing
95
loss e- is____?____agent?
oxidation, reducing
96
when the analyte is total cho for nutrition label, what is the method?
Grams of carbohydrate per serving is calculated as total grams of serving minus (g of moisture + g of protein + g of lipid + g of ash)
97
when the analyte is total cho for nutrition label, what is the principle?
Total carbohydrate by difference
98
when the analyte is total cho for nutrition label, what is the ad/disad?
Indirect and less accurate method Method is required by US regulations. Should not be used to calculate caloric content because carbohydrate components of dietary fiber, such as cellulose, provide essentially nocalories
99
when the analyte is total cho, what is the method?
Spectrophotometric, | phenolsulfuric acid
100
when the analyte is total cho, what is the principle?
Measures all Carbohydrates except sugar alcohols
101
when the analyte is total cho, what is the ad/disad?
Solution must be clear, | Requires a standard curve made with the same exact mixture of carbohydrates in the same ratio that occurs in the sample
102
when the analyte is total reducing sugar, what is the method?
Spectrophotometric. Somogyi- Nelson and related methods
103
when the analyte is total reducing sugar, what is the principle?
Primarily used to measure glucose/dextrose, maltose, and other low-molecular-weight oligosaccharides in glucose syrups
104
when the analyte is total reducing suagr, what is the ad/disad?
May require extraction Solution must be clear
105
when the analyte is Glucose/dextrose Sucrose, Lactose, what is the method?
1) Enzymic assay using GOPOD reagent (spectrophotometric) (2) HPLC
106
when the analyte is Glucose/dextrose Sucrose, Lactose, what is the principle?
Both methods specifically determine the amount of glucose in a mixture of sugar
107
when the analyte is Glucose/dextrose Sucrose, Lactose, what is the ad/disad?
Higher Specificity Extraction required.
108
when the analyte is fructose, what is the method?
高效液相色谱法（英语：high performance liquid chromatography，縮寫HPLC
109
when the analyte is fructose, what is the principle?
Specific determination of fructose in a mixture of sugars
110
when the analyte is fructose, what is the ad/disad?
N/A
111
when the analyte is starch, what is the method?
(1) Hydrolysis of starch to glucose using a mixture of amylases and determination of glucose using the (GOPOD) reagent (2) Hydrolysis of starch with glucoamylase and determination of glucose with glucose oxidase
112
when the analyte is starch, what is the principle?
Specific for starch, including modified starches
113
when the analyte is starch, what is the ad/disad?
Does not measure resistant starch. Sample | must be free of glucose or a correction made for it. Amylases must be purified to remove any interfering activities
114
when the analyte is pectin, what is the method?
Spectrophotometric. m-Hydroxydiphenyl-sulfuric acid method
115
when the analyte is pectin, what is the principle?
Uronic acid
116
when the analyte is pectin, what is the ad/disad?
Extraction may be required. Standard curve is required. Other hydrocolloids containing uronic acids will interfere
117
when the analyte is dietary fiber, what is the method?
Gravimetric (residue after removal of lipids, digestible starch, and protein and subtraction of ash content)
118
when the analyte is dietary fiber, what is the principle?
“Total dietary fiber
119
when the analyte is dietary fiber, what is the ad/disad?
Does not include low-molecular- weight soluble dietary fiber. Is not a measure of the physiological efficacy of the particular dietary fiber. Soluble and insoluble dietary fiber can be determined by specific methods for them

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