Chemistry Reference
In-Depth Information
Galacto-oligosaccharides
-
are oligosaccharides composed primarily of galactose monomers
linked together in a number of different structural configurations.
They usually consist of a number of
(1
!
6) linked galactopyranosyl
units linked to a terminal glucopyranosyl residue via an
(1
!
4)
glycosidic bond. They are sometimes referred to as trans-galacto-
oligosaccharides (TOSs).
-
abbreviations used are GOS and TOS.
Lactulose
(4-O-b-
D
-Galactopyranosyl-
D
-fructofuranose;
C
12
H
22
O
11
;FW
342.30 Da)
-
is an isomer of lactose, wherein the glucose moiety of lactose is
converted by alkaline isomerization to fructose. The disaccharide,
lactulose, is therefore composed of
-
D
-galactose linked to
-
D
-
fructose in a (1
!
4) configuration.
Lactosucrose ( b-
D
-Fructofuranosyl-4-O-b-
D
-galactopyranosyl-a-
D
-glucopyrano-
side; C
18
H
34
O
17
; FW 522 Da)
-
is a trisaccharide formed from lactose and sucrose by an enzymatic
transglycosylation.
Lactitol (4-O-b-
D
-Galactopyranosyl-
D
-glucitol; C
12
H
24
O
11
; FW 344.32 Da)
-
is a sugar alcohol derived from lactose by catalytic hydrogenation.
-
synonyms are lactit, lactositol, lactobiosit
Lactobionic acid (4-O-b-
D
-Galactopyranosyl-
D
-gluconic acid; C
12
H
22
O
12
;FW
358.30 Da)
-
is an oxidation product of lactose.
Tagatose (
D
-(-)-Tagatose; C
6
H
12
O
6
; FW 180.16 Da)
-isa
D
-lyxo-hexulose with a molecular weight of 180.16. It can occur
naturally and is derived from galactose by alkaline isomerization.
Prebiotic
-
a prebiotic is a selectively fermented ingredient that allows specific
changes, in both the composition and/or the activity in the gastro-
intestinal microflora, that confer benefits upon host well-being and
health (Gibson et al., 2004; Roberfroid, 2007). These ingredients are
normally restricted to certain carbohydrates (particularly oligosac-
charides), but could include certain proteins, peptides and lipids. The
concept of a prebiotic ingredient arose initially from the idea of
