Chemistry and Functional Properties of Carbohydrates and Sugars (Monosaccharides, Disaccharides, and Polysaccharides) - Sweeteners: Nutritional Aspects, Applications, and Production Technology - page 16

α-Pyranose β-Pyranose

Acyclic form of aldehyde

α-Furanose β-Furanose

Figure 2.5 Conversion from acyclic to cyclic forms of sugars.

CHO

OH

H

OH

H

H OH

H

O

H

O

HO H

HO

HO

H

HO

H OH

HO OH

H

OH

H

OH

H OH

H OH

H H

CH 2 OH

α-Pyranose form (38%) Aldehyde form (0.0026%) β-Pyranose form (62%)

H H

H OH

HO O

HO O

HO HO

HO H HO H

H H

OH H

<<1%

OH OH

H H

α-Furanose form β-Furanose form

Figure 2.6 Isomer forms of glucose in an aqueous solution at room temperature.

CH 2 OH

OH

O

CH 2 OH

O

C O

OH HO C H

OH

H
H

C OH
OH

OH CH 2 OH

OH OH

C

OH

OH

CH 2 OH

α-Pyranose form (traces) Keto form β-Pyranose form (75%)

CH 2 OH CH 2 OH

CH 2 OH OH

O

O

HO

HO

OH CH 2 OH

OH OH

α-Furanose form (4%) β-Furanose form (21%)

Figure 2.7 Isomer forms of fructose in an aqueous solution at room temperature.