1. Field of the Invention
The invention resides in the field of the treatment of protein solutions and more particularly relates to methods for improving the quality of liquid whey by demineralizing and lactose separation.
2. Description of the Prior Art
The treatment of liquid whey to increase the desirable protein content and decrease the ash and lactose components has been the object of a variety of processes described in the prior art. It is widely recognized that electrodialysis is an excellent method for separating undesirable ash or demineralizing whey which results as a by-product of various cheese manufacturing operations. U.S. Pat. No. 3,615,664, L. H. Francis, discloses a technique in which lactose is removed from whey by concentration of the raw whey resulting in lactose crystallization, crystal removal by hydraulic or centrifugal separation, heating to eliminate residual crystals and clarifying. The resultant whey is then subjected to electrodialysis to effect demineralization. Similarly, U.S. Pat. No. 3,447,930, by the same inventor, describes the process in reverse, that is, first demineralizing by electrodialysis and then separating lactose from the whey by the above procedure. U.S. Pat. No. 3,687,682, J. R. Schneder, discloses an improved electrodialysis cell arrangement which is used to remove ash from whey after which lactose is again removed by concentration and crystallization.
These and other prior art methods consist of innovative techniques directed to the purpose of obtaining a refined high protein whey end product which is suitable for use as a food ingredient. Among the concerns which arise in carrying out these processes are the denaturation of whey protein, lactalbumin, during the application of heat to effect concentration and crystallization; clogging of electrodialysis cells by protein precipitates; the speed, volume, and efficiency of operation; and the energy requirements of the processing equipment.
It has now been found that many of the difficulties of previous methods may be overcome by removing lactose from demineralized whey by the technique of forced flow electrophoresis as opposed to crystallization. Additionally, the percentage solids content of the whey is substantially increased at the same time since a large amount of liquid is removed simultaneously with the lactose. The benefits of this approach are several, among which are the minimization of heat which leads to a certain amount of denaturation, the elimination of numerous separate pieces of equipment which are required for concentration and crystallization, and the ability to create a compact processing unit utilizing basic electrolytic cell apparatus which may be arranged in a stack configuration combining both the electrolysis and electrophoresis process.
Forced flow electrophoresis is a method for separating and/or concentrating ions or molecules contained in a liquid by employing a hydrodynamic force and an electric current. An electrophoresis apparatus is used having liquid flow compartments defined by neutral and ionically charged membrane separators. The electrophoresis technique is fully disclosed in the prior art such as U.S. Pat. Nos. 2,878,178, 3,519,549, 3,829,370 and others.