Abstract: Reduction of ash and titratable acidity in liquid whey is accomplished by electrodialysis, without substantial precipitate formation, by passing at least a portion of the whey through a demineralization unit composed of a number of whey streams each bounded on both sides by brine streams, the streams being separated by cation and anion membranes arranged in an alternate sequence; and passing at least a portion of the whey through a deacidification unit composed of a plurality of whey streams bounded by a brine stream on one side and by a caustic solution stream on the other, the streams being separated by the sequence of cation-anion-anion-cation-etc., membranes wherein the whey stream is disposed between a pair of anion membranes.