A method for the production of prebiotic preparations containing isomaltooligosaccharides
and gluconic acid.
Dorothée Goffin 1,2, Christophe Blecker 2, Yves Malmendier 3, Michel Paquot
1
Department of Industrial Biological Chemistry, University of Liège, Gembloux Agro-Bio Tech, Passage des Déportés, 2, B-5030, Gembloux, Belgium
2 Department of Food Technology, University of Liège, Gembloux Agro-Bio Tech, Passage des Déportés, 2, B-5030, Gembloux, Belgium
3 Meurens Natural S.A., Rue des martyrs, 21, B-4650, Herve, Belgium
1
Isomaltooligosaccharides (IMOs) are non-digestible oligosaccharides, considered as prebiotics and therefore aim to selectively feed probiotics indigenous
to the human colon. They consist of glucose monomers linked by at least one α-1-6, or in a lower proportion α -1-3 (nigerose family) or α -1-2 (kojibiose
family) glucosidic linkages.
In our case they are produced enzymatically using an Aspergillus niger transglucosidase (EC 2.4.1.24) starting from either corn, tapioca, or rice hydrolyzed
starch and result in very complex mixture. However, the reaction only permits to reach yields between 50-85 % in IMOs. Impurities are composed of
residual maltooligosaccharides (glucose with exclusively α -1-4 linkages) from the starting vegetal material and glucose released during the
transglucosylation step. These digestible saccharides are deleterious for the prebiotic preparation and must therefore be eliminated from the medium.
In our original method, residual maltooligosaccharides are thus specifically hydrolyzed by a thermostable α-glucosidase (EC. 3.2.1.20) in order to produce
glucose as the only unwanted specie. This glucose can then be converted to gluconic acid and/or its salts using a glucose-oxidase (EC. 1.1.3.4) in
combination with a catalase. Gluconic acid (C6H12O7) is a saccharide derivative with various health benefits and has been recognized as a prebiotic
compound.
Gluconic acid can then be left in the medium in order to obtain an original product enjoying new prebiotic potential properties or separated using an
anion-exchange resins (Dowex AcO-) as gluconic acid is charged compared to glucose.
Transglucosylation
Released maltooligosaccharides or glc
OH
Transgluco
sylation
*
HO
O
HO
Glc
OH
OH OH
Target oligosaccharide
OH
O
HO
HO
OH
HO
*
OH O
OH O*
H
OH
OH
OH
α-(1-4)
α-(1-3)
O
HO
Substrates = glucooligosaccharides with
preferably α-(1-4) at the reducing end
Substrate : Maltose, glucose, α-(1-4)
and rarely α-(1-6) glucooligosaccharides
α-(1-6)
HO
O
HO
MT2
4--D-glucosyl-D-glucose
O
OH
HO
OH O
α-(1-2)
O
H
HO
OH
OH
Tranglucosylation with Aspergillus niger transglucosidase starting from either corn, tapioca or rice hydrolyzed starch
OH
α-(1-2)
HO
OH
OH
HOCH2
O
HO
O
α-(1-3)
HO
HO
HOCH2
OH
OH
HO
O
HO
OH
HO
2
3
O
OH
n
6
HO
HO
OH
O
3
O
HO
O
IMO (50-85%)
O
HO
OH O
4
OH
OH
O
Panose
OH OH
-D-Glcp-(1-6)--D-Glcp-(1-4)-D-Glcp
6
H
HO
Pure Nigero- family
O
O
α-(1-6)
OH
6
O
n
2
mixte
HO
HO
OH
O
HO
OH
O
HO
O
O
HO
O
HO
HO
OH
HO
OH
O
O
HO
Pure classical IMO family
OH
Residual maltose and
maltooligosaccharides
n
OH OH
Released glucose and
maltooligosaccharides
Pure Koji- family
Membrane
separation
digestible saccharides =
deleterious
for
the
prebiotic
preparation  must be eliminated
from the medium.
Selective
fermentation
Classical purification methods
 Expensive equipment
Adsorption
Process
 Low DP IMO loss
 Low efficiency
 Low column capacity
Cheap and popular
Doesn’t get rid of all digestibles
Loss of part of IMO
Use of living organisms
 Need for recycling
Productivity Problem : loss of the digestible fraction
Gluconic acid method
1
Selective enzymatic
hydrolysis (α-glucosidase)
2
Selective enzymatic glucose-oxydation
(glucose-oxydase + catalase)
Glucoseoxydation
New original product containing
two prebiotic compounds :
IMO and gluconic acid
 without loss of the digestible
fraction
Released glucose and
maltooligosaccharides
 with new nutri-functional and
techno-functional properties
Glucose
Glucose
Gluconic acid
Residual maltose and
maltooligosaccharides
In conclusion, this overall process, fulfilling the principles of green chemistry and being applicable to produce organic prebiotic, is an elegant solution, from
an economical, environmental, nutri-functional and techno-functional point of view. Indeed, it can lead to original prebiotic preparations, with yields close to
100%, by avoiding product loss, as the digestible saccharides portion is converted to gluconic acid. Furthermore, gluconic acid can also provide many
functional properties to the prebiotic preparations for their incorporation in food products.
Process for the production of a composition, the composition and the use there-of as food additive’. Goffin D., Paquot M., Blecker C., Robert C. European patent, n°PCT/EP2010/050596
published on 22 july 2010 under number 2010/081913.