Method for producing a mixture of neutral oligosaccharides extracted from flaxseed

A method for obtaining a composition of neutral oligosaccharides extracted from flaxseed, said oligosaccharides having high molecular weights, said method including the following steps:

• carrying out a hydrolysis at acidic pH on a solution of flax mucilage, said flax mucilage being obtained by extraction from flaxseed in a solvent;
• neutralizing said solution by adding a base in an adequate quantity so as to form a neutralized solution;
• carrying out a first ultrafiltration of said neutralized solution through a membrane with a porosity of 50,000 Da so as to obtain a first retentate and a first permeate;
• carrying out a second ultrafiltration of said first permeate through a membrane with a porosity of 15,000 Da so as to obtain a second retentate and a second permeate;
• carrying out a third ultrafiltration of said second permeate through a membrane with a porosity of 5,000 Da so as to obtain a third retentate and a third permeate;
• and
• mixing said second retentate and said third retentate in order to obtain a mixture of oligosaccharides, said second retentate being comprised of oligosaccharides having molar weights resulting from fractionation by said second ultrafiltration at a cutoff point between 15,000 and 50,000 Da, and said third retentate being comprised of oligosaccharides having molar weights resulting from fractionation by said third ultrafiltration at a cutoff point between 5,000 and 15,000 Da.