Appendix. Nondigestible Carbohydrates: Structure and Sources

Transcription

1 Appendix s: Structure and s A primer on carbohydrate structure Numbering System: Carbon molecules are numbered successively from the carbon group containing the aldehyde group (before cyclization) counterclockwise. In the case of fructose, the second carbon is the carbon extending from the anomeric carbon. 6 C O 2 5 O 4 O O 1 O 3 2 O s and Digestive ealth Edited by Teri M. Paeschke and William R. Aimutis 2011 Blackwell Publishing Ltd. and Institute of Food Technologists. ISBN:

2 322 s and Digestive ealth Alpha and Beta Convention: The alpha glycosidic linkage is below the plane of the rings and the beta glycosidic linkages is above the plane of the rings. C O 2 C O 2 O O O O O O O O O O Alpha (α) Beta ( β) D and L Convention: The designation of D or L is based on the configuration around the next to the last carbon atom, counting the carbon with the aldehyde group as C1. For sugars with more than one chiral center, the D or L refers to chiral carbon farthest from the aldehyde or keto group. CO CO O O O O O O O O C O 2 C O 2 D-Glucose L-Glucose

3 Appendix 323 Monosaccharide of Non-digestible s α- D-p β- D-p β- D-pA α- L-GulpA α- D-Galp β- D-Galp α- D-GalpA α-d-manp β- D-Manp β- D-ManpA

4 324 s and Digestive ealth α- D-Xylp β- D-Xylp α-l-rhap α-l-fucp α-l-araf β-l-araf β- D-Fruf

5 Appendix 325 Abbreviations of Common Monosaccharide : Saccharide -D-Glucose -D-Glucose -D-Galactose -D-Galactose -D-Mannose -D-Mannose -L-Fucose -D-Fructose -L-Rhamnose -D-Xylose -D-xylose -L-Arabinose -L-Arabinose -D-Galacturonic Acid -D-Guluronic Acid -D-Mannuronic Acid -D-Glucuronic Acid Abbreviation -D-p -D-p -D-Galp -D-Galp -D-Manp -D-Manp -L-Fucp -D-Fruf -L-Rhap -D-Xylp -D-Xylp -L-Araf -L-Araf -D-GalpA -D-GulpA -D-ManpA -D-pA Dietary Fiber s, Monosaccharide, Structures, and Structure, Fructans Inulin Fructooligosaccharide (FOS), oligofructose (OFS) Chicory root, jerusalem artichoke ydrolyzed chicory root extract and enzymic synthesis from sucrose Fru Fru (2 1) linked fructose, often with a terminal glucose (2 1) linked fructose, often with a terminal glucose (Continued)

6 326 s and Digestive ealth Structure, Levan Galactans Galactooligosaccharide Synthetic s Polydextrose Resistant maltodextrin Grain, fruits and vegetable oligo and Pectin Enzymic synthesis from sucrose, plants Enzymic synthesis from lactose obtained from whey Catalytic synthesis from glucose, sorbitol, and citric or phosphoric acid Corn or wheat starch pyrolysis, with subsequent enzyme digestion Most often citrus based, sugar beet, fruits, and vegetables Fru Gal Gal, Man, Rha,, Xyl, Fuc, A (2 6) linked fructose, with branches of (2 1) linked fructose Varies widely by manufacturer and enzyme choice: Galactose linked (1 4), and/or (1 6), and/or (1 3) Randomly linked glucose units, and (1 2), (1 3), (1 4), (1 6) linkages, with (1 6) predominating Randomly linked glucose units and (1 2), (1 3), (1 4), (1 6) Very complex heteropolymer, backbone of galacturonic acid linked (1 4), various side chains and substitutions on the backbone w/rhamnose, glucose, xylose, mannose, fucose, glucuronic acid

7 Appendix 327 Structure, -Glucan Oats, barley Repeating tetraose and triose units of (1 4) and (1 3) glucose Cellulose Cell wall structural (1 4) linked glucose emicellulose Arabinoxylan Arabinoxylooligosaccharides material in plants Cell wall structural material in plants Grain-based materials, most often wheat or corn ydrolyzed grain arabinoxylan: wheat and corn most common Xyl, Ara Xyl, Ara, sources Psyllium usk from Plantago Xyl, Ara, Gal, Rha, GalA Very complex heteropolymer of xyloglucans, arabinoxylans, etc. often linked with ferulic acid eteropolymer with a backbone of (1 4) linked xylose and side chains of arabinose Oligosaccharides from arabinoxylan, see above Complex heteropolymer, xylose backbone linked (1 4) and (1 3) sidechains of Ara, Xyl, Gal, Rha, GalA also present Larch gum Larch tree Gal, Ara ighly branched galactose backbone linked (1 3) Resistant starches Type 1 Physically inaccessible, seeds and unprocessed grains Crystalline (1 4) linkages (Continued)

8 328 s and Digestive ealth Structure, Type 2 Type 3 Type 4 Glactomannan Ungelatinized, crystalline high amylose starches Retrograded, crystalline, corn starch Chemically crosslinked starch, corn, wheat, tapioca, etc. Crystalline (1 4) linkages Crystalline (1 4) linkages Varies by process and manufacturer (1 4)-linked mannan backbone with (1 6) linked galactose side chains (substitution ratio) depends on source Guar gum Legume/seed Gal, Man Ratio of mannose to galactose (M:G) ratio 2:1 ydrolyzed guar gum Legume Gal, Man see guar above, low viscosity Locust bean Legume/seed Gal, Man M:G ratio 4:1 gum, aka carob Fenugreek gum Legume/seed Gal, Man M:G ratio 1:1 Tara gum Legume/seed Gal, Man M:G ratio 3:1 Microbial Xanthan gum Exocellular polysaccharide from xanthamonus campestrus, Man, A (1 4) cellulose backbone w/side chains of (3 1) -linked trisaccharide chain of ( -D-Man- (2 1)- -D-A acid (4 1)- -D-Man) on alternating glucose residues

9 Appendix 329 Structure, Gellan gum Exocellular polysaccharide from Sphingomonas elodea, Rha, A Seaweed Alginate Brown seaweed A, ManA Repeating tetrasaccharide [ (1 4) A (1 4)-D- (1 4)-L-Rha (1 3)] n Linear block copolymer of glucuronic and mannuronic acids Glucomannan Konjac Tuber/root, Man (1 4)-linked mannose and glucose Tree exudate Gum arabic, gum acacia Karaya, tragacanth, and ghatti gums Tree resin Tree resin Gal, Ara, Rha, A Gal, Xyl, Rha, Man, A, GalA ighly branched heteropolymer with some protein moeities, galactose backbone linked (1 3), numerous and extensive branches of galactose, arabinose, rhamnose ighly branched and very complex heteropolymers varying greatly by species, climate, etc. Pectic components maybepresent.