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Join food industry consultant John D. Keller, Jr. for lectures on carbohydrates in food science, classification, metabolism, and structure. Explore monosaccharides, oligosaccharides, and polysaccharides.
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FOOD CARBOHYDRATES Spring - 2013John D. Keller, Jr. (MS) Food Industry Consultant Visiting Professor Rutgers Office: By Appointment Home Office: (732) 308-4427 (P/Fax); E-Mail: jdkjrfreehold@verizon.net
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ADMINISTRATIVE I • Lecture/Exam Schedule • Exams/Quizes • Lectures/Notes http://foodsci.rutgers.edu/carbohydrates
http://foodsci.rutgers.edu/carbohydrates alginking
ADMINISTRATIVE II • References • CHO Chem for Food Sci’s • http://interactive.aaccnet.org/source/orders/index.cfm?task=3&CATEGORY=BKH01&SKU=27533 • Food Chemistry – Fennema, 4th ed. • Adv Org Chem • Handbook of Hydrocolloids • Miscellaneous • Classes
Introduction I • Definition/Nomenclature • CHO Classification • CHO Metabolism • Carbohydrates in Foods Aliphatic polyhydroxy cpds which usually carry a carbonyl group
Carbohydrate = Carbon Hydrate i.e., C(H2O) or Cn(H2O)n , or C6(H2O)6 = C6H12O6 CO2 +H2O Sugar + O 2↑
A A B E C E B C D D Introduction II • Definition/Nomenclature • Chiral Carbons mirror http://www.chem.qmul.ac.uk/iupac/2carb/
Simple Sugar Nomenclature IPrefixes and Suffixes • ALDO- = 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
Simple Sugar Nomenclature II • ISOMERS = 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
CHO Classification I • Monosaccharides • Oligosaccharides • Polysaccharides
CHO Classification II • Monosaccharides • Open chain • Cyclic forms • Planar, Haworth projection • 3-dimensional
H CH2OH C O O H C OH OH C H OH OH H C OH OH C H OH OH CH2OH D-glucose &b -D-glucopyranose 6 1 2 5 3 1 4 4 2 5 3 6 Fischer Projection Haworth Projection
b -D-glucopyranose 6 4 5 2 1 3
CHO Classification III • Monosaccharides • Open chain • Cyclic forms • Planar, Haworth projection • 3-dimensional • 5 and 6 carbon most common
CHO Classification IV • Oligosaccharides • Disaccharides • Sucrose • Maltose • Lactose • Higher Oligosaccharides
CHO Classification V • Polysaccharides • > 20 monosaccharide units • Homo- and heteroglycans • Linear • Branched
O O O O O O O O O O O O O O O O O O O O O O O O O RE O O Mannose “backbone” RE O O O O O O O O Galactose “side groups” Substituted Linear vs Branched Polymers linear branched
CHO Metabolism I • Contributions to diet • Major source of calories • 4 Kcal/g • Texture, sweetness • Simple vs complex CHOs
CHO MetabolismII • Enzyme activity • Main means of digestion • On specific sugars
CHO 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 CHOs • Glycemic Index (Response) http://www.diabetes.ca/for-professionals/resources/nutrition/glycemic-index/
Carbohydrate Structure I • Monosaccharides • Glycosides • Oligosaccharides • Polysaccharides
Carbohydrate Structure II • Monosaccharides • Important ones • D-glyceraldehyde source • Aldoses & Ketoses • Isomerization
O O =CHO = CH2OH O O =OH O O O O O O O O O O O O *= new asymetric center Rosanoff Shorthand D-Triose Aldoses Fig 3.3, p 86 D-Glycerose D-Tetroses * * D-Erythrose D-Threose D-Pentoses * * * * D-Arabinose D-Xylose D-Lyxose D-Ribose D-Hexoses * * * * * * * * D-Talose D-Altrose D-Idose D-Galactose D-Glucose D-Mannose D-Gulose D-Allose
R O C O (H)(OH) C R =H or CH2OH D-Tetrose (D-Threose) Sacharose group
Ketoses CH2OH 1 C O 2 O C OH 3 C OH 4 C OH 5 CH2OH 6 D-Fructose
CH2OH Triulose C O CH3 CH2OH C O CH3 O O O O Tetruloses Pentuloses O O Hexuloses Ketoses Dihydroxyacetone (DHA) D-Erythrulose D-glycero-Tetrulose Acetone * D-Xylulose D-threo-Pentulose D-Ribulose D-erythro-Pentulose * * O * * * * D-Psicose D-Fructose D-Tagatose D-Sorbose (D-ribo-Hexulose) (D-arabino-Hexulose) (D-xylo-Hexulose) (D-xylo-Hexulose) (D-lyxo-Hexulose)
Carbohydrate Structure III • Monosaccharides • Important ones • D-glyceraldehyde source • Isomerization • Involves both carbonyl and adjacent hydroxyl groups (i.e., on the a-carbon)
H C H C O OH CH2OH C O-H C OH C O C C OH OH C OH C OH C OH C OH C C OH C OH OH CH2OH CH2OH CH2OH H C O OH H C OH HO C C C C OH OH C OH C OH C C OH OH CH2OH CH2OH Monosaccharide isomerization H D-Fructose trans-enediol (key intermediate) D-Glucose trans-enediol D-Mannose Fig 3.5, p 88