P1249616421jIPWB - PowerPoint PPT Presentation

Title: P1249616421jIPWB


1
CARBOHYDRATES
Carbohydrate - polyhydroxy aldehyde, ketones and
their derivatives. Functions - structure material
storage material for carbon and energy.
2
CONCEPTS OF ISOMERS
Two or more different compounds which contain the
same number and types of atoms and the same
molecular weights.   Projection formula (spatial
arrangement to represent 3-dimensional
structure)
3
D-glyceraldehyde (hydroxy group at the highest
numbered asymmetric carbon atom is written to the
right)
L-glyceraldehyde (hydroxy group at the highest
numbered asymmetric carbon atom is written to the
left) D-Erythrose is the mirror image of
L-Erythrose.
4
Glyceraldehydes Model compounds of
monosaccharides
D-Glyceraldehyde L-Glyceraldehyde
D-Erythrose L-Threose
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POLARIMETER
Dextrorotatory -plane polarized light rotated to
clockwise (or to the right) Levoratatory - plane
polarized light rotated to counterclockwise.
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FISHER PROJECTION FORM
Anomeric Carbon --- The carbon atom which is
involved in hemiacetal or acetal formation.
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Anomers Stereoisomers formed when ring is formed
(a, b).
a is same side with ring
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HAWORTH PROJECTION FORMULAS FOR SUGARS
a - D - Glucopyranose
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HAWORTH PROJECTION FORMULAS FOR SUGARS
a
-D-Glucopyranose
(35)
-D-Glucofuranose
a
(0.5)
Aldehydo-D-glucose
(0.03)
-D-Glucofuranose
b
b
-D-Glucopyranose
(0.5)
(0.5)
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MONOSACCHARIDE
Hexoses 1. Glucose (dextrose) --- rotate the
polarized light to the right.
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Glucose (dextrose)
Most common monosaccharide. Commercially from
starch. Cereal roots, legumes, animal tissue, and
liver.   Mutarotation --- The optical changes of
glucose in water solution to constant value
a20D 520    a - D - glucose -gt D -
glucose lt- b - D - glucose a20D 113 a20D
52 a20D 19 At equilibrium 35 of a -
form and 65 of b - form.
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2. Galactose --- Component of lactose (milk
sugar)
a-D-Galactopyranose
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3. Fructose (levulsoe) --- Rotation in
polarimeter is left
D-Fructose b-D-Fructose
a-D-Fructose
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Fructose (levulsoe)
b - D - Fructofuranose a - D -
Fructofuranose

Naturally-occurring free form
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Disaccharides (anydrides of 2 monosaccharides)
Maltose 4-0-a-D-Glucopyranosyl (1-gt4)
a-D-Glucopyranose
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Cellobiose 4-0-b-D-Glucopyranosyl
(1-gt4)-b-D-Glucopyranose
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Sucrose 2-0-a-D-Glucopyranosyl
b-D-Fructofuranoside
Invert Sugar --- when sucrose in solution, the
rotation changes from detrorotatory (66.5) to
levorotatory (-19.8). So, sucrose is called
Invert Sugar. Sucrose has been hydrolyzed into
glucose and fructose.
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Lactose Principal sugar in milk
4-0-b-D-Galactopyranosyl (1-gt4)-a-D-
Glucopyranose 4-0-b-D-Galactopyranosyl
(1-gt4)-b-D-Glucopyranose
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RELATIVE SWEETNESS OF DIFFERENT SUGARS
Sucrose 100 Glucose 74 Fructose 174 Lact
ose 16 Invert Sugar 126 Maltose 32 Galact
ose 32
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Oligosaccharide
Raffinose (Galactose Glucose
Fructose) 6-0-a-D-Galactopyranosyl
(1-gt6)-2-0-a-D-Glucopyranosyl (1-gt2)-b-D-Fructofur
anoside
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Stachyose (Galactose Galactose Glucose
Fructose) 6-0-a-D-Galactopyranosyl
(1-gt6)-6-0-a-D-Galactopyranosyl (1-gt 6)
-2-0-a-D-Glucopyranosyl-b-D-Fructofuranoside Flat
ulence Factor
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POLYSACCHARIDE
Anhydrides of Monosaccharides Through ether b
linkages. Cellulose --- polymer of b-D-Glucose
(1, 4) linkage. Repeating cellobiose moiety.
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STARCH
The reserve carbohydrate of plants. Occurs as
granules in the cell. Made of amylose and
amylopectin. Amylose --- ploymer of a-D- Glucose
(1-gt4) linkage-straight-chain.
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Amylopectin Polymer of a-D-Glucose (1-gt4)
linkage in addition to a-D-Glucose (1-gt6)
linkage. The length of linear units in
amylopectin is only 25. a-(1-gt4) linkage (25)
to a-(1-gt6) linkage.
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GLYCOGEN
Animal starch. a - (1 -gt 4) linkage and a - (1
-gt 6) linkage 12 1
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PECTIN
Polymer of 4-0-a-D-Galacturonic acid (1 -gt 4)
Methylgalacturonate
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DEGREE OF METHYLATION (DM)
The higher the degree of methylation, the higher
the temperature at which the gel forms.   For gel
formation at least 50 of the carboxyl group are
methylated. Pectin (about 74 DM) is used in
jams. For jellies DM is about 60.
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FUNCTIONAL PROPERTIES OF POLYSACCHARIDES (GUMS)
1. Viscosity control 2. Texture
control 3. Emulsifying agent 4. Water-binding
capacity 5. Stabilizer
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CORN SYRUP
The higher the DE, generally the greater the
glucose content in corn syrup.
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HIGH FRUCTOSE SYRUPS
Generally Glucose 50 Fructose
42 Maltose 1.5 Isomaltose 1.5 High
er Saccharides 5.0
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CORN SYRUP
 
Dry Weight
Glucose
9
14
43
Maltose
52
12
32
Triose
13
10
3
Tetrose
2
9
5
32
MODIFIED STARCHES
1.  Pregelatinized Starch --- simple precooked
and roll dried to give product that readily
disperses in cold water. 2.  Thin-boiling or
Acid-modified Starch --- suspending granular
starch in a very dilute acid under somewhat below
its gelatinization temperature (somewhat
mild). 3. Oxidized Starches --- oxidation of
starch with alkaline hypochloride to get -coo- at
C6.
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CARBOHYDRATE DETERMINATION
1. Monosaccharides and Oligosaccharides A. Enzyma
tic Method 1. Glucose oxidase 2. Hexokinase B
. Chromatography Method 1. Paper or thin layer
chromatography 2. Gas chromatography 3. Liquid
column chromatography   2. Polysaccharides
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Glucose Oxidase System
Glucose Oxidase D-Glucose O2
Gluconic Acid H2O2   
Peroxidase H2O2 0 - Dianisidine 2 H2O
Oxidized 0-Dianisidine (Colorless)
(Brown)
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Hexokinase System
Hexokinase Glucose ATP G - 6
- P ADP     G - 6 - P DH G - 6
- P NADP Gluconate - 6 -
phosphate NADPH H
NADP (Nicotinamide Adenine Dinucleotide
Phosphate)   The amount of NADPH formed in this
reaction is stoichiometric with the amount of
glucose. NADPH is measured by its absorption at
334 nm.
36
QUALITATIVE ANALYSES OF CARBOHYDRATES
Thin Layer chromatography Silica gel as
stationary phase (250 mm) Quantitative by
densitomer (time - varies with solvent, generally
overnight)
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Gas Liquid Chromatography Requirement compounds
must be volatile. Sugars form Trimethylsilyl
Ether
Ether linkage Trimethyl chlorosilane
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Liquid Chromatography Carbohydrate Analysis
(Waters Assocs. 840380 Stationary Phase)
Solvent H2O/CH3CN
39
POLYSACCHARIDES
Usually, quantitation depends on chemical or
enzymatic hydrolyses of them, followed by
analysis of the monomers. Starch 1. Amylose
I- -gt Blue complex Use spectrometer for
determining the amylose - iodine blue color -
according to spectrophotometric
reading. 2. Amylopectin I- -gt Reddish
color.