CARBYDRATES Basic Theory Alan H. King, Ph.D. Hydrocolloid Consultant Rutgers Adjunct Professor Rutgers ffice: Rm #321A, (848) 932-5552 Home ffice: (908) 233-5274; E-Mail: alginking@gmail.com
utline Introduction CH Structure Reactions of CHs Function of Simple CHs in Foods
Introduction Definition/Nomenclature CH Classification CH Metabolism Carbohydrates in Foods CHs = Aliphatic polyhydroxy compounds which carry a carbonyl group.
Carbohydrate = Carbon Hydrate i.e., C(H 2 ) or C n (H 2 ) n, or C 6 (H 2 ) 6 = C 6 H 12 6 C 2 +H 2 Sugar + 2
Simple Sugar Nomenclature -SE = free sugar, esp. aldose sugar -URNIC = -C (carboxyl) group at 1 o carbon -SIDE = substitution at anomeric carbon = glycoside -AN = polymer. E.g., glucan = glucose polymer Introduction to Food Science ISMERS = compounds with same chemical composition but different structures. (general term) STEREISMERS = isomers differing only in spacial arrangement of groups (e.g., - groups) ENANTIMERS = mirror image isomers (e.g., D- vs L- sugars) ANMERS = isomers differing only in position of anomeric carbon groups EPIMERS = Stereoisomers differing only in position of last asymmetric carbon groups
CH Classification I Monosaccharides ligosaccharides Polysaccharides
CH Classification II Monosaccharides pen chain Cyclic forms Planar, Haworth projection 3-dimensional 5 and 6 carbon most common
Glucose & -D-glucopyranose H C CH 2 H C C H H C H C CH 2 Fischer Projection (straight chain) Haworth Projection
-D-glucopyranose
CH Classification III Introduction to Food Science Monosaccharides pen chain Cyclic forms Planar, Haworth projection 3-dimensional 5 and 6 carbon most common
CH Classification IV ligosaccharides (2 20 monos) Disaccharides Sucrose Maltose Lactose Higher ligosaccharides
CH Classification V Polysaccharides > 20 monosaccharide units Homo- and heteroglycans Linear Branched
Linear vs Branched Polymers linear Mannose backbone RE branched RE RE = reducing end Substituted Galactose side groups
CH Metabolism I Contributions to diet Major source of calories 4 Kcal/g Texture, sweetness Simple vs complex CHs
CH Metabolism II Enzyme activity Main means of digestion n specific sugars
CH Metabolism III Dietary fiber Indigestible polysaccharides Function of Sweetness Positives Negatives
Carbohydrates in Foods Naturally present 3/4 of dry weight Sucrose Fruit Cereals Animal products Added CHs Introduction to Food Science
Free Sugars in Fruit (% Fresh vs (Dry) Basis) Introduction to Food Science Fruit D-Glucose D-Fructose Sucrose % H 2 Apple 1.17 (7.5) 6.04 (38.7) 3.8 (24.2) 84.4 Grape 6.86 (37.3) 7.84 (42.6) 2.2 (12.2) 81.6 Peach 0.91 (8.3) 1.18 (10.8) 6.9 (63.5) 89.1 Pear 0.95 (5.7) 6.77 (40.3) 1.6 (9.6) 83.2 Cherry 6.49 (33.1) 7.38 (37.7) 0.22 (1.1) 80.4 Strawberry 2.09 (20.7) 2.4 (23.8) 1.03 (10.2) 89.9
Free Sugars in Vegetables (% Fresh vs (Dry) Basis Basis) Vegetable D-Glucose D-Fructose Sucrose % H 2 Beet 0.18 (1.4) 0.16 (1.3) 6.1 (48.1) 87.3 Carrot 0.85 (7.2) 0.85 (7.2) 4.2 (35.9) 88.2 nion 2.07 (19) 1.1 (10) 0.9 (8.2) 89.1 Spinach 0.09 (1) 0.04 (0.4) 0.06 (0.6) 90.7 Sweet corn 0.34 (1.2) 0.3 (1.1) 3.0 (11.1) 72.7 Tomato 1.1 (17.2) 1.3 (20.6) 0.01 (0.2) 93.5
Sugars in Common Foods Food Sugar present(%) Soft Drinks 9 Cracker 12 Ice cream 18 Ready-to-eat cereals (dry) 1-50 range juice 10 Catsup 29 Cake (dry mix) 36 Jello (dry) 83
Carbohydrate Structure I Monosaccharides Glycosides ligosaccharides Polysaccharides
Carbohydrate Structure II Monosaccharides Important ones D-glyceraldehyde source
= CH = CH 2 D-Glycerose D-Triose Aldoses D-Tetroses = D-Erythrose D-Pentoses D-Threose D-Ribose D-Arabinose D-Xylose D-Lyxose D-Hexoses D-Allose D-Altrose D-Glucose D-Mannose D-Gulose D-Idose D-Galactose D-Talose
Carbohydrate Structure III Monosaccharides Important ones D-glyceraldehyde source Straight chain does not explain all Rxs Ring formation Mutarotation Haworth projection
H 1 C RING FRMATIN 2 4 C C C 3 5 C 6 CH 2 4 6 CH 2 5 3 1 2
Glucose Anomers: Hemiacetals Reducing sugars Mutarotate 1 2 4 5 C C C C C 3 4 6 CH 2 5 3 2 1 Ring opens here - Mutarotation 6 CH 2 Ring here for furanose -D-Glucose (m.p. 146 o, [ ] = +112 o ) -D-Glucose (m.p. 150 o, [ ] = +19 o ) or
HAWRTH PRJECTIN D- L- 4 6 CH 2 5 3 2 1 { L-) D-) { D-) L-) D-GLUCSE D-Glucopyranose)
Carbohydrate Structure IV Glycosides Alcohol + acid - H 2 Physiological function Base stable, acid labile Rx with other sugars
Glycosides CH 2 CH 2 aglycon + R H + R + H 2 D-glucose alkyl D-glucopyranoside
Carbohydrate Structure V ligosaccharides Disaccharides Homogeneous Heterogeneous
H CH 2 CH 2 D glucopyranosyl-(1 4)- D glucopyranose Maltose H CH 2 CH 2 H D glucopyranosyl-(1 6)- D glucopyranose Isomaltose Disaccharides of Glucose H CH 2 CH 2 H D glucopyranosyl-(1 4)- D glucopyranose Cellobiose CH 2 H CH 2 D glucopyranosyl-(1 6)- D glucopyranose Gentiobiose CH 2 H 2 HC H D glucopyranosyl-(1 1)- L glucopyranoside Trehalose
Heterogeneous Disaccharides CH 2 CH 2 H hemiacetal -Lactose -D-galactopyranosyl (1-4)- -D-glucopyranose CH 2 1 H 1 CH 2 5 2 H 4 CH 2 3 6 Sucrose -D-glucopyranosyl-(1-2)- -D-fructofuranoside
Carbohydrate Structure VI ligosaccharides Disaccharides Homogeneous Heterogeneous Reducing vs Non-reducing Higher ligosaccharides
Heterogeneous Disaccharides CH 2 CH 2 H hemiacetal -Lactose -D-galactopyranosyl (1-4)- -D-glucopyranose CH 2 1 H 1 CH 2 5 2 H 4 CH 2 3 6 Sucrose -D-glucopyranosyl-(1-2)- -D-fructofuranoside
Carbohydrate Structure VII Polysaccharides General Starch (I) Source Composition Amylose Amylopectin Structure
Starch Granules I Introduction to Food Science Tapioca Granules Wheat Granules Potato Granules
Starch Granules II Rice Granules Corn Granules
Carbohydrate Structure VIII Polysaccharides General Starch (I) Source Composition Amylose (linear) Amylopectin (branched)
Amylose Introduction to Food Science Amylose The Helical Structure Amylose Fractions Showing the Helical Structure
1,6 Linkage Amylopectin 1,4 Linkage ^^^ Amylopectin Amylopectin Branching
Starch Source Amylose % Amylopectin % Corn 25-28 72-75 Tapioca 17 83 Waxy maize Nil 99+
Carbohydrate Structure IX Polysaccharides Starch (II) Granules Gelatinization Rx with Iodine
Structrue of molecules in layer of a starch granule. Thickened areas represent micelles produced by association of chains
Carbohydrate Structure X Polysaccharides Starch (II) Granules Gelatinization Rx with Iodine
Starch Granules III Introduction to Food Science Micrograph of Potato Starch Granules Micrograph of Potato Starch Granules (polarized light shows Maltese Cross) A B
Brabender Swelling Profiles at 6% Solids
Starch Rx w/ I 2 Clathrates Model of an iodine-filled amylose helix (Rundle, Foster, and Baldwin, 1944)
Polysaccharides Starch (III) Modification Why? Crosslinking Stabilization Retrogradation Freeze/Thaw stability Introduction to Food Science Carbohydrate Structure XI
Starch granule structure Introduction to Food Science X = Cross-linking; H = Hydrogen bonding Gel phase Micelles Cross-linking to supplement hydrogen bonding in a starch granule Stabilization> > (Complements of NATINAL STARCH) ^ = Blocking action =Stabilizing agent
Reactions of Carbohydrates I Hydrolysis Acyclic CH Reactions CH Dehydration/Thermal degradation Browning Reactions - nonenzymatic
Reactions of Carbohydrates II Hydrolysis Mechanism Products of hydrolysis Corn Syrups Compositions DE (dextrose equivalents)
Reactions of Carbohydrates III Hydrolysis Starch (Amylose), considered as a condensation polymer of glucose
Typical, Commercial HFCS Products Components Normal 55% Fructose 90% Fructose Glucose 52 40 7 Fructose 42 55 90 ligosaccharides 6 5 3 Relative sweetness 100 105 140
Reactions of Carbohydrates IV Acyclic CH Reactions Ring size transitions Mutarotation Enolization - Lobry de Bruyn- Alberda van Ekenstein Rx
Glucose Equilibrium Cpds -D-glucofuranose 0.003% -D-glucopyranose D-glucose (aldehydo-dglucose) -D-glucofuranose -D-glucopyranose Interconversion of D-glucose isomers in aqueous solution
Reactions of Carbohydrates VI D-glucose enediol D-glucose, D-mannose D-fructose Lobry de Bruyn-Alberda van Ekenstein reaction of D-glucose.
Reactions of Carbohydrates VII CH Dehydration/Thermal degradation Browning Reactions - non-enzymatic Caramelization Enolization Dehydration Polymerization
hydroxyacetylfuran enediol 3-deoxyosone 3,4-dideoxyosone hydroxymethylfurfural (HMF) Formation of hydroxymethylfurfural by dehydration of a hexose enediol
Reactions of Carbohydrates VIII Browning Reactions - non-enzymatic Caramelization Maillard reaction Amino groups Reducing sugar Water Positive vs negative effects Controlling the Rx
http://food.oregonstate.edu/color/maillard/nancy.html
Function of Simple CHs in Foods I Reactions with other Ingredients Water Flavors Sweeteners Alcohols Bulking Agents
= 6 Glu = 7 Glu = 8 Glu Host Molecule Guest Molecule Schardinger dextrin Bacillus macerans amylase
Sugar Alcohols; Sweetness Sugar alcohol Relative sweetness Xylitol 90 Sorbitol 63 Galactitol 58 Maltitol 68 Lactitol 35 Sugar alcohols in tap water at 25 o C Sucrose = 100
Function of Simple CHs in Foods II Bulking Agents Maltodextrins Polydextrose
Dietary Fiber NEW DIETARY FIBER DEFINITIN - Dietary fiber is the edible parts of plants or analogous carbohydrates that are resistant to digestion and absorption in the human small intestine with complete or partial fermentation in the large intestine. Dietary fiber includes polysaccharides, oligosaccharides, lignin, and associated plant substances. Dietary fibers promote beneficial physiological effects including laxation, and/or blood cholesterol attenuation, and/or blood glucose attenuation.
Polydextrose Composition % Polymer Glucose Sorbitol Levoglucosan Water Sulphated ash