Process for purifying amino acids

Claim 1

A PROCESS FOR THE PURIFICATION OF AN AQUEOUS MEDIA OF PROTEIN HYDROLYZATE HAVING A PH BETWEEN 5.5 AND 7 AND CONTAINING, AS ESSENTIAL CONSTITUENTS, AMINO ACIDS CONTAMINATED WITH COLORED AND ODOROUS IMPURITIES, WHICH COMPRISES: (A) ELECTRODIALYZING, AT A CURRENT DENSITY OF ABOUT 0.3 TO 0.8 AMPERE PER SQUARE DECIMETER, A PORTION OF THE SAID AQUEOUS MEDIA OF PROTEIN HYDROLYZATE CONTAMINATED WITH COLORED AND ODOROUS IMPURITIES, FROM A PURIFICATION ZONE CHARGED WITH SAID AQUEOUS MEDIA OF PROTEIN HYDROLYZATE AND DISPOSED INTERMEDIATE TWO ELECTRODE ZONES HAVING A POSITIVE AND A NEGATIVE ELECTRICAL POTENTIAL, RESPECTIVELY, IN THE DIRECTION TOWARD SAID POSITIVE ELECTRODE ZONE THROUGH AN ANIONPERMSELECTIVE ZONE CONSISTING ESSENTIALLY OF SOLID, POROUS ANION-EXCHANGE RESIN POLYMER HAVING A WATER CONTENT BETWEEN 45% AND ABOUT 60% BY WEIGHT, SAID ANION-EXCHANGE RESIN POLYMER BEING A QUATERNARY AMMONIUM SALT OF A BUTADIENE-STYRENE COPOLYMER HAVING A BUTADIENE-STYRENE RATIO, BY WEIGHT, OF FROM 70:30 TO 30:70 CALCULATED ON THE DRY COPOLYMER, AND SIMULTANEOUSLY IN THE DIRECTION TOWARD THE NEGATIVE ELECTRODE ZONE THROUGH A CATION-SELECTIVE ZONE CONSISTING ESSENTIALLY OF SOLID, POROUS, SULFONIC ACID, CATION-EXCHANGE RESIN POLYMER HAVING A WATER CONTENT BETWEEN 40% AND ABOUT 60% BY WEIGHT, AND THE DEGREE OF CROSS-LINKING IN BOTH ION-EXCHANGE MATERIALS CORRESPONDING TO MEAN PORE SIZES IN THE RANGE OF ABOUT 5 TO 20 ANGSTROMS, INTO ELECTRICALLY CONDUCTIVE AQUEOUS MEDIA IN ELECTRODIALYTICAL CONTACT WITH SAID ZONES OF SAID ANION- AND OF SAID CARBON-EXCHANGE RESIN POLYMERS, RESPECTIVELY, WHEREBY THE AFORESAID PORTION OF THE SAID AQUEOUS MEDIA OF PROTEIN HYDROLYZATE MIGRATES TOGETHER WITH SAID IMPURITIES OUT OF SAID PURIFICATION ZONE, AND (B) INTERRUPTING THE ELECTRODIALYSIS AS SOON AS THE AMINO ACID SOLUTION IN SAID PURIFICATION ZONE HAS ATTAINED A DETERMINED DEGREE OF PURITY.