Brewing Science

• Molecular formula (CH2O)n

Carbohydrate: A polyhydroxyaldehyde or polyhydroxyketone, or a substance that gives these compounds on hydrolysis. Monosaccharide: A carbohydrate that cannot be hydrolyzed to a simpler carbohydrate.

Aldose: A monosaccharide containing an aldehyde group. Ketose: A monosaccharide containing a ketone group.

Monosacharides

In 1891, Emil Fischer made the arbitrary assignments of D- and L- to the enantiomers of glyceraldehyde.

CHO CHO H OH HO H

CH2OH CH2OH D-Glyceraldehyde L-Glyceraldehyde [α]25 = +13.5° [α]25 = -13.5° D D – D-monosaccharide: the -OH on its penultimate carbon is on the right in a Fischer projection. – L-monosaccharide: the -OH on its penultimate carbon is on the left in a Fischer projection. Epimers

Hemiacetals and Hemiketals Cyclization

H 1 O 1 H 1C O H C H O C H H 2 OH H 2 OH H 2 OH O O HO 3 H HO 3 H HO 3 H H 4 OH H 4 OH H 4 OH H 5 H 5 O H H 5

6 6 6 CH2OH CH2OH CH2OH α-D-glucose D-glucose β-D-glucose Pyranoses and Furanoses Haworth Projections D-Fructose (a 2-ketohexose) also forms a five-membered cyclic hemiacetal.

1 HOCH2 O CH2OH 5 H HO 2 H OH(α) HO H 1 CH2OH 2 C=O α-D-Fructofuranose HOCH2 O OH (β) HO H (α-D-Fructose) 5 H HO 2 H OH H CH2OH 5 1 H OH HO H CH2OH D-Fructose β-D-Fructofuranose (β-D-Fructose)

HOCH2 OH OH OH O O OH

CH2OH HO CH2OH HO HO

β-D(–)-fructofuranose β-D(–)-fructopyranose

(Honey) Chair Conformations • For pyranoses, the six-membered ring is more accurately represented as a chair conformation. anomeric carbon CH2OH HO O HO OH(β) OH β-D-Glucopyranose (β-D-Glucose) CH OH 2 CH2OH HO OH HO O HO O HO C OH H HO OH(α) D-Glucose α-D-Glucopyranose (α-D-Glucose) Chain-ring Equilibrium and Reducing Sugars The Glycosidic Bond Disaccharides Sweetness Monosaccharides are colorless crystalline solids, very soluble in water, but only slightly soluble in ethanol.

Sweetness relative to sucrose:

Sweetness Sweetness Relative to Artificial Relative to Carbohydrate Sucrose Sweetener Sucrose fructose 1.74 saccharin 450 sucrose (table sugar) 1.00 acesulfame-K 200 honey 0.97 aspartame 180 glucose 0.74 sucralose 600 maltose 0.33 galactose 0.32 lactose (milk sugar) 0.16 starch starch

• amylose • amylopectin • dextrins starch

α (1,4)

• amylose • amylopectin • dextrins starch

α (1✌4)

• amylose • amylopectin • dextrins starch

α (1✌6) α (1✌4)

• amylose • amylopectin • dextrins starch

• amylose • amylopectin • dextrins glycogen cellulose

β (1,4) Maltose and Cellobiose Sucrose Raffinose and Melibiose Maltotriose and Dextrins Starch Granule Starch Breakdown

http://braukaiser.com/wiki/index.php?title=Starch_Conversion Starch Conversion

http://braukaiser.com/wiki/index.php?title=Starch_Conversion