CARBOHYDRATES

Definition Polyhydroxy aldehyde, ketones and their derivatives. C6 (H2O)6, C12 (H2O)11, C18 (H2O)16 Functions Storage material for carbon and energy.

Concepts of Isomers C6 (H2O)6, C12 (H2O)11, C18 (H2O)16 Two or more different compounds which contain the same number and types of atoms and the same molecular weights.  C6 (H2O)6, C12 (H2O)11, C18 (H2O)16 Projection formula: Spatial arrangement to represent 3-dimensional structure

CHO H C OH CH OH CHO HO C H CH OH 2 D-glyceraldehyde (Hydroxy group at the highest numbered asymmetric carbon atom is written to the right): CHO HO C H CH OH 2 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.

Glyceraldehyde D-Glyceraldehyde L-Glyceraldehyde Model Compounds of Monosaccharides D-Glyceraldehyde L-Glyceraldehyde H O H O C C H C OH HO C H CH OH CH OH 2 2 D-Erythrose L-Threose H O H O C C H C OH H C OH H C OH HO C H CH OH CH OH 2 2

Mirror Image of Glucose H H C O O C H C O H H O C H H O C H H C O H H C O H H O C H H C O H H O C H C H O H C H O H 2 2 L-glucose D-glucose

Fisher Projection Form OH HO H C C C H C OH H C OH H C OH HO C H HO C H O HO C H O or H C OH H C OH H C OH H C OH H C H C CH OH CH OH CH OH 2 2 2 Anomeric Carbon --- The carbon atom which is involved in hemiacetal or acetal formation.

Mirror Image of Glucose H H O H H O C C H C O H H O C H H O C H O O H C O H H C O H H O C H H C C H C H O H C H O H 2 2 - L-glucose -D-glucose

Anomers Stereoisomers formed when ring is formed (a, b). C O CH 2 OH H HO or a is same side with ring

Six and Five Member Rings o o Furan Pyran

Fisher & Harworth Projection Forms OH OH O HO CH 2 1 3 4 5 6 C H C OH HO C H O H C OH H C CH OH 2 a - D - Glucopyranose

a- and b- Glucose

a-Glucose b-Glucose

- L-glucose -D-glucose H H O H H O C C H C O H H O C H H O C H O O H 2 2 - L-glucose -D-glucose C H O H H 2 O O H H O H O H H C H O H 2 O H H H O H O H O H H H H O H O H H

MONOSACCHARIDES

Glucose a-D-Glucopyranose 6 CH O 5 4 1 HO OH 3 H OH C H C OH HO C H O 2 1 3 4 5 6 C H C OH HO C H O H C OH H C CH OH 2 a-D-Glucopyranose

Fisher Projection Form HO C O CH 2 OH H a -D-Glucopyranose (35%) a -D-Glucofuranose (0.5%) Aldehydo-D-glucose (0.03%) b -D-Glucofuranose (0.5%) b -D-Glucopyranose (65%)

Galactose Component of lactose a-D-Galactopyranose CH OH HO O OH OH OH 2 HO O OH OH OH a-D-Galactopyranose

Fructose D-Fructose b-D-Fructose a-D-Fructose CH OH CH OH CH OH HO OH 2 HO 2 2 OH C O C C HO C H HO C H HO C H O or O H C OH H C OH H C OH H C OH H C H C CH OH CH OH CH OH 2 2 2 D-Fructose b-D-Fructose a-D-Fructose

Naturally-occurring free form Fructose HOCH O HOCH CH OH 2 OH O 2 2 HO HO CH OH 2 OH OH OH b - D - Fructofuranose a - D - Fructofuranose O OH CH 2 H C HO Naturally-occurring free form

Anydrides of 2 monosaccharides Disaccharide Anydrides of 2 monosaccharides

Linkage of Monosaccharides

Maltose 4-0-a-D-Glucopyranosyl- a-D-Glucopyranose CH OH CH OH O O OH 2 2 O O OH OH HO O OH OH OH

Cellobiose 4-0-b-D-Glucopyranosyl -b-D-Glucopyranose CH OH CH OH O O 2 2 O O OH O OH OH HO OH OH

2-0-a-D-Glucopyranosyl b-D-Fructofuranoside Sucrose 2-0-a-D-Glucopyranosyl b-D-Fructofuranoside O OH HO CH 2 H 1 5 2 3 4 6 Invert sugar is the hydrolyzed sucrose into glucose and fructose.

Lactose Principal sugar in milk CH OH CH OH 2 2 OH O O O OH OH OH OH OH 4-0-b-D-Galactopyranosyl-a-D- Glucopyranose 4-0-b-D-Galactopyranosyl-b-D-Glucopyranose

Relative Sweetnes of Sugars Sucrose 100 Glucose 74 Fructose 174 Lactose 16 Invert Sugar 126 Maltose 32 Galactose 32

Oligosaccharides

Raffinose 6-0-a-D-Galactopyranosyl-2-0-a-D-Glucopyranosyl -b-D-Fructofuranoside

Stachyose 6-0-a-D-Galactopyranosyl-6-0-a-D-Galactopyranosyl -2-0-a-D-Glucopyranosyl-b-D-Fructofuranoside “Flatulence Factor” CH OH 2 OH O CH 2 CH O O OH 2 OH O O CH OH O OH 2 OH OH HO OH OH O CH OH 2 OH OH

Polysaccharides

Cellulose Polymer of b-D-Glucose (1, 4) linkage. Repeating cellobiose moiety. O OH CH 2 n

Cellulose

Starch The reserve carbohydrate of plants. Occurs as granules in the cell. Made of amylose and amylopectin. Amylose --- Polymer of a-D- Glucose (1->4) linkage-straight-chain.

Amylose

Amylopectin Polymer of a-D-Glucose (1->4) linkage in addition to a-D-Glucose (1->6) linkage. The length of linear units in amylopectin is only 25. a-(1->4) linkage (25) to a-(1->6) linkage.

Amylose and Amylopectin

Glycogen Animal starch. a - (1 -> 4) linkage and a - (1 -> 6) linkage 12 : 1

Glycogen

Glycogen

Pectin Polymer of 4-0-a-D-Galacturonic acid (1 4) & Methylgalacturonate COOH COOCH COOCH COOH 3 3 OH O O O O O O O O O OH OH OH OH OH OH OH OH OH OH OH OH

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.

Functions of Carbohydrates

Functions of Polysaccharides 1. Viscosity control 2. Texture control 3. Emulsifying agent 4. Water-binding capacity 5. Stabilizer

Corn Syrup Enzyme Corn Starch Corn Syrup + H High Glucose D Maltose Dextrose Gram of Reducing Sugar Dextrose Equivalent (DE) = x 100 Gram of Total Sugar The higher the DE, generally the greater the glucose content in corn syrup.

Amylose

High Fructose Syrups Generally: Glucose 50% Fructose 42% Maltose 1.5% Glucose Isomerase Glucose in Syrup Fructose Generally: Glucose 50% Fructose 42% Maltose 1.5% Isomaltose 1.5% Higher Saccharides 5.0%

Corn Syrup High Maltose Syrup Low DE High DE Glucose 9 14 43 Maltose     High Maltose Syrup Low DE High DE % Glucose 9 14 43 Maltose 52 12 32 Triose 13 10 3 Tetrose 2 9 5 Pentose 24 55 12

Modified Starches

Amylose

Modified Starches 1.  Pregelatinized Starch --- Precooked and roll dried starch to give product that readily disperses in cold water. 2.  Thin-boiling or Acid-modified Starch --- Suspended granular starch in a very dilute acid under somewhat below its gelatinization temperature. 3. Oxidized Starches --- Oxidation of starch with alkaline hypochloride to get -COOH at C6.

Amylose

Carbohydrate Determination

Determination 1. Monosaccharides and Oligosaccharides A. Enzymatic Method 1. Glucose oxidase 2. Hexokinase B. Chromatography Method 1. Thin layer chromatography 2. Gas chromatography 3. Liquid column chromatography   2. Polysaccharides

a- and b- Glucose

Glucose Oxidase System D-Glucose + O2 Gluconic Acid + H2O2    H2O2+ 0 - Dianisidine 2 H2O + Oxidized 0-Dianisidine (Colorless) (Brown) Glucose Oxidasse Peroxidase

Gluconic Acid, Glucouronic Acid and Gluconolactone H O O O O H C C H C O H H C O H H H O C H H O C H O H + H C O H H C O H H H C H C O H C H O H C H O H 2 2 Gluconic Acid Glucouronic Acid Gluconolactone

Hexokinase System Glucose + ATP G - 6 - P + ADP   G - 6 - P + NADP+ Gluconate - 6 - phosphate + NADPH + H+ Hexokinase G-6-P DH G-6-P DH: Glucose-6-phosphate dehydrogenase NADP+ : Nicotinamide Adenine Dinucleotide Phosphate NADPH : Reduced Nicotinamide Adenine Dinucleotide Phosphate The NADPH formed in this reaction is stoichiometric with the amount of glucose. NADPH is measured at 334 nm.

G-6-Phosphate + NADP+ Gluconate-6-phosphate + NADPH + H 2 P H C O 2 P + + + NAPD+ NADPH + H

NADP + C O N H 2 O - N + O P O C H 2 O O H O H O N H 2 N N N N - O P O PO3H2

NADPH - - + H+ CONH2 H N O O P O C H O O H O H O N H N N N N O P O C H PO3H2

Qualitative Analysis Thin Layer chromatography Silica gel as stationary phase Quantitation by densitomer Solvent For Spot A C A B Rf = S S A B A

Gas Chromatography Ether linkage Trimethyl chlorosilane Requirement: Compounds must be volatile. Sugars form Trimethylsilyl Ether. Ether linkage Trimethyl chlorosilane

Derivation of Glucose with Trimethylchlorosilane OH O HO CH 2 1 3 4 5 6 Si CH 3 5Cl + Glucose Trimethylchlorosilane 6 CH O-Si(CH3)3 2 O 5 + 5HCl 4 1 O-Si(CH3)3 (CH3)3-Si-O O-Si(CH3)3 3 2 O-Si(CH3)3

Liquid Chromatography Stationary Phase: Waters Associates. 840380 Solvent: H2O/CH3CN

Polysaccharides Quantification depends on chemical or enzymatic hydrolyses of them into monomers and analysis of the monomers. Qualitative Analyses 1. Amylose + I- Blue color Use spectrometer for determining the amylose - iodine blue color 2. Amylopectin + I- Reddish color

Summary