1 / 39

CARBOHYDRATES

CARBOHYDRATES. Carbohydrate - polyhydroxy aldehyde, ketones and their derivatives. Functions - structure material storage material for carbon and energy. CONCEPTS OF ISOMERS . Two or more different compounds which contain the same number and types of atoms and the same molecular weights.

tiara
Download Presentation

CARBOHYDRATES

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

  5. POLARIMETER Dextrorotatory -plane polarized light rotated to clockwise (or to the right) Levoratatory - plane polarized light rotated to counterclockwise.

  6. FISHER PROJECTION FORM Anomeric Carbon --- The carbon atom which is involved in hemiacetal or acetal formation.

  7. Anomers: Stereoisomers formed when ring is formed (a, b). a is same side with ring

  8. HAWORTH PROJECTION FORMULAS FOR SUGARS a - D - Glucopyranose

  9. OH H OH H C C H C OH H C OH O HO H HO C H C O H C H C OH H C H C OH CH OH CH OH 2 2 H O C H C OH HO H C H C OH H C OH CH OH 2 HO H H HO C C H C OH H C OH O HO H C HO H C O H C H C OH H C OH H C CH OH 2 CH OH 2 HAWORTH PROJECTION FORMULAS FOR SUGARS a -D-Glucopyranose (35%) a -D-Glucofuranose (0.5%) Aldehydo-D-glucose (0.03%) b -D-Glucofuranose b -D-Glucopyranose (0.5%) (0.5%)

  10. MONOSACCHARIDE Hexoses 1. Glucose (dextrose) --- rotate the polarized light to the right.

  11. 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 -> D - glucose <-b - D - glucose a20D = 113 a20D = 52 a20D = = 19 At equilibrium = 35% of a - form and 65% of b - form.

  12. 2. Galactose --- Component of lactose (milk sugar) a-D-Galactopyranose

  13. 3. Fructose (levulsoe) --- Rotation in polarimeter is left D-Fructose b-D-Fructose a-D-Fructose

  14. Fructose (levulsoe) CH OH CH OH 2 2 OH H C O C CH OH O 2 HO HO H H C C OH H H O C C OH OH OH OH H H C OH C OH OH H C CH OH 2 H b - D - Fructofuranose a - D - Fructofuranose Naturally-occurring free form

  15. Disaccharides (anydrides of 2 monosaccharides): Maltose: 4-0-a-D-Glucopyranosyl (1->4) a-D-Glucopyranose

  16. Cellobiose 4-0-b-D-Glucopyranosyl (1->4)-b-D-Glucopyranose

  17. 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.

  18. Lactose Principal sugar in milk 4-0-b-D-Galactopyranosyl (1->4)-a-D- Glucopyranose 4-0-b-D-Galactopyranosyl (1->4)-b-D-Glucopyranose

  19. RELATIVE SWEETNESS OF DIFFERENT SUGARS Sucrose 100 Glucose 74 Fructose 174 Lactose 16 Invert Sugar 126 Maltose 32 Galactose 32

  20. Oligosaccharide Raffinose (Galactose + Glucose + Fructose) 6-0-a-D-Galactopyranosyl (1->6)-2-0-a-D-Glucopyranosyl (1->2)-b-D-Fructofuranoside

  21. Stachyose (Galactose + Galactose + Glucose + Fructose) 6-0-a-D-Galactopyranosyl (1->6)-6-0-a-D-Galactopyranosyl (1-> 6) -2-0-a-D-Glucopyranosyl-b-D-Fructofuranoside “Flatulence Factor”

  22. POLYSACCHARIDE Anhydrides of Monosaccharides Through ether b linkages. Cellulose --- polymer of b-D-Glucose (1, 4) linkage. Repeating cellobiose moiety.

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

  24. 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.

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

  26. PECTIN Polymer of 4-0-a-D-Galacturonic acid (1 -> 4) & Methylgalacturonate

  27. 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.

  28. FUNCTIONAL PROPERTIES OF POLYSACCHARIDES (GUMS) 1. Viscosity control 2. Texture control 3. Emulsifying agent 4. Water-binding capacity 5. Stabilizer

  29. CORN SYRUP The higher the DE, generally the greater the glucose content in corn syrup.

  30. HIGH FRUCTOSE SYRUPS Generally: Glucose 50% Fructose 42% Maltose 1.5% Isomaltose 1.5% Higher Saccharides 5.0%

  31. High Maltose Syrup Low DE High DE Pentose 24 55 12 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.

  33. CARBOHYDRATE DETERMINATION 1. Monosaccharides and Oligosaccharides A. Enzymatic Method 1. Glucose oxidase 2. Hexokinase B. Chromatography Method 1. Paper or thin layer chromatography 2. Gas chromatography 3. Liquid column chromatography 2. Polysaccharides

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

  35. 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):

  37. Gas Liquid Chromatography Requirement: compounds must be volatile. Sugars form Trimethylsilyl Ether: Ether linkage Trimethyl chlorosilane

  38. 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- -> Blue complex Use spectrometer for determining the amylose - iodine blue color - according to spectrophotometric reading. 2. Amylopectin + I- -> Reddish color.

More Related