1 FOOD CARBOHYDRATES Spring - 2013 John D. Keller, Jr. (MS)Food Industry Consultant Visiting Professor Lecture #1 - Simple Sugars - Classification/Structures/Nomenclature Rutgers Office: By Appointment Home Office: (732) (P/Fax);
2 The "Campus Operating Status" page has been posted as a service Info on closings, etc. Suggest you make an icon on your desktop! The "Campus Operating Status" page has been posted as a service to the campus community and can be found at or by going to the main New Brunswick webpage at . The "Campus Operating Status" page has been posted as a service to the campus community and can be found at or by going to the main New Brunswick webpage at .
3 ADMINISTRATIVE I Lecture/Exam Schedule Exams/Quizes Lectures/Notes
4 alginking
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6 ADMINISTRATIVE II References CHO Chem for Food Sci’s Food Chemistry – Fennema, 4th ed. Adv Org Chem Handbook of Hydrocolloids Miscellaneous Classes
7 CHO Chem for Fd Scientists, 2nd EdCHO Chem for Fd Scientists, 2nd Ed. (ca $169, from AACC) (see site below)
8 Aliphatic polyhydroxy cpds which usually carry a carbonyl groupIntroduction I Definition/Nomenclature CHO Classification CHO Metabolism Carbohydrates in Foods Aliphatic polyhydroxy cpds which usually carry a carbonyl group
9 Carbohydrate = Carbon Hydratei.e., C(H2O) or Cn(H2O)n , or C6(H2O)6 = C6H12O6 CO2 + H2O Sugar + O 2 ↑
10 Definition/NomenclatureIntroduction II Definition/Nomenclature Chiral Carbons A D E B C A D E B C mirror
11 Simple Sugar Nomenclature I Prefixes and SuffixesALDO- = carbonyl at #1 carbon, i.e., an aldehyde KETO- = carbonyl at #2 carbon, i.e., a ketone -OSE = free sugar, esp. aldose sugar -ULOSE = free keto sugar -ITOL = CHO alcohol w/ two 1o -OH groups -ONIC = -COOH (carboxyl) group at anomeric carbon -URONIC = -COOH (carboxyl) group at 1o carbon -ARIC = -COOH (carboxyl) groups at both ends of the sugar molecule (e.g., #1 & #6 carbons) -OSIDE = substitution at anomeric carbon = glycoside -AN = polymer. E.g., glucan = glucose polymer
12 Simple Sugar Nomenclature IIISOMERS = compounds with same chemical composition but different structures. (very general term, e.g. family of isomers with C6H12O6 formula) STEREOISOMERS = isomers differing only in spatial arrangement of groups (e.g., -OH groups, like D-glu, D-man, etc.) ENANTIOMERS = mirror image isomers (e.g., corresponding D- vs L- sugars) ANOMERS = isomers differing only in position of -OH groups at anomeric carbons (i.e., a- vs b- isomers) EPIMERS = Stereoisomers differing in position of -OH groups at only one asymmetric carbon
13 CHO Classification I Monosaccharides Oligosaccharides Polysaccharides
14 CHO Classification II Monosaccharides Open chain Cyclic formsPlanar, Haworth projection 3-dimensional
15 D-glucose & b -D-glucopyranoseH O CH2OH OH 6 1 O CH2OH OH 2 5 3 4 1 4 2 5 3 6 Fischer Projection Haworth Projection
16 b -D-glucopyranose 6 4 5 2 1 3
17 CHO Classification IIIMonosaccharides Open chain Cyclic forms Planar, Haworth projection 3-dimensional 5 and 6 carbon most common
18 CHO Classification IV Oligosaccharides Disaccharides Sucrose MaltoseLactose Higher Oligosaccharides
19 CHO Classification V Polysaccharides > 20 monosaccharide unitsHomo- and heteroglycans Linear Branched
20 Linear vs Branched PolymersRE O RE linear branched Mannose “backbone” Substituted Galactose “side groups”
21 CHO Metabolism I Contributions to diet Major source of calories4 Kcal/g Texture, sweetness Simple vs complex CHOs
22 CHO Metabolism II Enzyme activity Main means of digestionOn specific sugars
23 CHO Metabolism III Dietary fiber Indigestible polysaccharidesFunction of Sweetness Positives Negatives
24 Carbohydrates in Foods“Naturally” present 3/4 of dry weight Sucrose Fruit Cereals Animal products Added CHOs Glycemic Index (Response)
25 Free Sugars in Fruit (% Fresh vs (Dry) Basis)
26 Free Sugars in Vegetables (% Fresh vs (Dry) Basis Basis)
27 Sugars in Common Foods
28 Carbohydrate Structure IMonosaccharides Glycosides Oligosaccharides Polysaccharides
29 Carbohydrate Structure IIMonosaccharides Important ones D-glyceraldehyde source Aldoses & Ketoses Isomerization
30 *= new asymetric Aldoses O O O O O O O O O O O O O O O = CHO = CH2OHcenter Rosanoff Shorthand O D-Triose Aldoses O = CHO = CH2OH = OH O O Fig 3.3, p 86 D-Glycerose * * D-Tetroses D-Erythrose D-Threose D-Pentoses O O O O * * * * D-Arabinose D-Xylose D-Lyxose D-Ribose D-Hexoses O O O O O O O * * * * * * * * D-Allose D-Altrose D-Glucose D-Mannose D-Gulose D-Idose D-Galactose D-Talose
31 R C (H)(OH) O R = H or CH2OH O D-Tetrose (D-Threose) Sacharose group
32 Ketoses 1 CH2OH 2 C O O OH C 3 4 C OH 5 C OH 6 CH2OH D-Fructose
33 Dihydroxyacetone (DHA)Ketoses CH2OH C O Triulose Tetruloses Pentuloses Hexuloses Dihydroxyacetone (DHA) CH3 C O D-Erythrulose D-glycero-Tetrulose O Acetone * O O D-Ribulose D-erythro-Pentulose D-Xylulose D-threo-Pentulose * * O O O O * * * * D-Psicose D-Fructose D-Sorbose D-Tagatose (D-ribo-Hexulose) (D-arabino-Hexulose) (D-xylo-Hexulose) (D-xylo-Hexulose) (D-lyxo-Hexulose)
34 Carbohydrate Structure IIIMonosaccharides Important ones D-glyceraldehyde source Isomerization Involves both carbonyl and adjacent hydroxyl groups (i.e., on the a-carbon)
35 Monosaccharide isomerization trans-enediol (key intermediate)CH2OH C OH O H CH2OH C O-H OH H CH2OH OH C O H D-Fructose trans-enediol (key intermediate) D-Glucose CH2OH C HO OH O H CH2OH C OH H trans-enediol D-Mannose Fig 3.5, p 88