Carbohydrates z Polyhydroxy compounds (poly-alcohols) that contain a carbonyl (C=O) group z Elemental composition C x(H 2O) y z About 80% of human caloric intake z >90% dry matter of plants z Functional properties – Sweetness – Chemical reactivity – Polymer functionality
Carbohydrates z Polyhydroxy compounds (poly-alcohols) that contain a carbonyl (C=O) group z Elemental composition C x(H 2O) y z About 80% of human caloric intake z >90% dry matter of plants z Functional properties – Sweetness – Chemical reactivity – Polymer functionality
Types of Carbohydrates
Types of Carbohydrates
Monosaccharides z Monosaccharides are categorized by the number of carbons (typically 3-8) and whether an aldehyde or ketone z Most abundant monosaccharides are hexoses (6 carbons) z Most monosaccharides are aldehydes, i.e. aldoses C C H O H OH C C O H H OH aldehyde ketone
Monosaccharides z Monosaccharides are categorized by the number of carbons (typically 3-8) and whether an aldehyde or ketone z Most abundant monosaccharides are hexoses (6 carbons) z Most monosaccharides are aldehydes, i.e. aldoses C C H O H OH C C O H H OH aldehyde ketone
Fisher projections H OH H OH H OH HO H C C C C C C H 2OH H O H OH H OH O HO H C C C C C H OH 2 C H OH 2 1 2 3 4 5 6 D-glucose (an aldohexose) D-fructose (an ketohexose) 1 2 3 4 5 6
Fisher projections H OH H OH H OH HO H C C C C C C H 2OH H O H OH H OH O HO H C C C C C H OH 2 C H OH 2 1 2 3 4 5 6 D-glucose (an aldohexose) D-fructose (an ketohexose) 1 2 3 4 5 6
Six carbons =0 H H H H 0 H H- OH HO-C-H H-C-OH HO-C-H H-C-OH HO-C-H H-C -OH HO-C-H H-C-OH H-C-OH HO- -C-H HO-C-H H-C-OH H-C-OH HO- C-H HO-C-H H-C-OH H-C-OH H-C-OH H-C-OH HO-C-H HO-C-H HO-C-H HO-C-H H-C-OH H-C-OH H-C-OH H-C-OH H-C一OH H-C-OH H-C -OH H-C一OH CH2OH CH2OH CH2OH CH2OH CH2OH CH2OH CHOH CH2OH D-Allose D-Altrose D-Glucose D-Mannose D-Gulose D-Idose D-Galactose D-Talose D-Aldoses (a)