Carbohydrates

Review of sugar nomenclature:

D-Glucose
L-Glucose
Rosanoff-Hudson Rule

Monosaccharides

Trioses - C3

Glyderaldehyde

Tetroses - C4

Erythrose
Threose

Pentoses C5

Ribose
Arabinose
Xylose
Lyxose

Hexose C6

Aldoses

Glucose

Galactose

Ketoses

Fructose

Sorbose

Optical Rotation

+ dextro - right
- levo - left

Haworth Perspective
Cis-Trans isomerization

Glucose isomers in aqueous solutions:

Intensity of Carbonyl band - O-Fructose inwater as a function of temperature:

Fructose isomers in aqueous solutions:

Open chain form of fructose:

Increases with increasing temperature - 20-80° C
Increases 12 x at pH 7.0 when temperature increases from 30-80° C
Temperature effect is reversible 20-80° C
Carbonyl peak is maximal after 10 minutes at any given temperature

Mutarotation

% distribution at 20° C

alpha-D Glucose +112.2° => +52.7°
beta-D-Glucose + 18.7° => +52.7°

Stability of glucose and fructose.

Sugar pH of optimum stability

Glucose 4.0
Fructose 3.0
Stability is independent of temperature and concentration at these pH values.
Epimers - Differ at positions other than C1

		C-2 epimer		C-4 epimer

Heptuloses 

Pentoses

Deoxysugars

Boat and Chair

Dissacharides are made up of two monosaccharides. The three most common are shown below:

Sucrose

Lactose

Maltose

Some oligosaccharides are of importance in foods such as:

Raffinose

Stachyose

Sucralose

Starch

Cellulose