Patent GB-1081453-A (GB)
Title: Method of fractionating polysaccharide mixtures
Inventor: MANN SEYMOUR HERBERT
IPC: C08B37/00
Filed: 1965-03-02
Abstract: A heterogeneous mixture of polysaccharides is separated into fractions having lower and higher average degree of polymerization (D.P.) by introducing into the upper portion of a liquid-liquid contacting zone an aqueous solution containing not more than 30% by weight of the polysaccharide mixture, introducing into the lower portion of the zone a water-miscible organic solvent, the ratio of organic solvent to water in the zone being 1:1 to 6:1; withdrawing from the upper portion of the zone (at a location above the point of introduction of the aqueous polysaccharide solution) a solution of polysaccharides of lower average D.P. and withdrawing from a location below the point of introduction of the organic solvent a solution of polysaccharides of higher average D.P., the temperature within the zone being maintained at 0-75 DEG  C.  The heterogeneous polysaccharide mixture may be derived from starches, amylose or amylopectin and may comprise corn starch dextrin or corn syrup solids.  The organic solvent may be an alkanol, ketone, cyclic ether or mixtures thereof, and may also be a solvent/water mixture provided the required ratio of solvent to water in the contacting zone is maintained.  The contacting zone, through which the aqueous polysaccharide solution and the organic solvent are passed counter-current, may be a vertical cylindrical column filled with bubble plates, Raschig rings, grids etc.  In an example, a fraction of D.P. 1.25 (substantially glucose) is separated from corn syrup using isopropanol as solvent in a column maintained at 25-30 DEG C.ALSO:A heterogeneous mixture of polysaccharides is separated into fractions having lower and higher average degree of polymerization (D.P.) by introducing into the upper portion of a liquid-liquid contacting zone an aqueous solution containing not more than 30% by weight of the polysaccharide mixture, introducing into the lower portion of the zone a water-miscible organic solvent, the ratio of organic solent to water in the zone being 1:1 to 6:1; withdrawing from the upper portion of the zone (at a location above the point of introduction of the aqueous polysaccharide solution) a solution of polysaccharides of lower average D.P. and withdrawing from a location below the point of introduction of the organic solvent a solution of polysaccharides of higher average D.P., the temperature within the zone being maintained at 0-75 DEG  C.  The heterogeneous polysaccharide mixture may be derived from starches, amylose or amylopectin and may comprise corn starch dextrin or corn syrup solids.  The organic solvent may be an alkanol, ketone, cyclic ether or mixtures thereof, and may also be a solvent/water mixture provided the required ratio of solvent to water in the contacting zone is maintained.  The contacting zone, through which the aqueous polysaccharide solution and the organic solvent are passed counter-current, may be a vertical cylindrical column filled with bubble plates, Raschig rings, grids &c.  In an example, a fraction of D.P./.25 (substantially glucose) is separated from corn syrup using isopropanol as solvent in a column maintained at 25-30 DEG  C.