Demineralization of cheese whey

Despite the first industrial ED application in the food sector dated back to 1960 and concerned the demineralization of cheese whey for use in baby foods, the history of ED is longer than that usually acknowledged (Shaposhnik and Kesore, 1997). 

Hiraoka Y, Itoh K, and Taneya S. Demineralization of cheese whey and skimmed milk by electrodialysis with ion exchange membranes. Milchwiss 1979 34 397-400. 

The use of electrodialysis in food, drug, and chemical industries has been studied quite extensively in recent years. Several applications have considerable economic significance and are already well established today. One is the demineralization of cheese whey [46]. Normal cheese whey contains between 5.5 and 6.5 % of dissolved solids in water. The primary constituents in whey are lactose, protein, minerals, fat and lactic acid. Whey provides an excellent source of protein, lactose, vitamins, and minerals, but in its normal form it is not considered a proper food material because of its high salt content. With the ionized salts substantially removed, whey provides an excellent source for the production of babyfood. The partial demineralization of whey can be carried out quite efficiently by electrodialysis. 

The valuable component of cheese whey is not the lactose but the whey proteins, primarily lactalbumin. The amino acid profile of these proteins is superior nutritionally to casein and is equal to or better than whole egg protein. The heat-denatured form of these proteins has been manufactured for many years usually by heating the cheese whey to precipitate the proteins. The product was tan colored and completely insoluble. With the advent of UF, these proteins could be recovered, concentrated and demineralized athermally. The result was a "whey protein concentrate" (WPC) with improved solubility and other functional properties (emulsification, foamability, water binding, gelation and cloud stability). 

Cheese whey demineralization Desalting of protein hydrolysates (i.e., soy sauce), sugar solutions, molasses, and polysaccharide dispersions Deacidification of fruit juices Tartaric wine stabilization Flavor recover from pickle brines... 

During electrodialysis treatment, total Mg " " concentration in the STW diminished from 980 to 800 ppm in 30 min a 18.4% decrease from the initial concentration. This decrease in Mg concentration is due to Mg migration, from the STW solution to the concentrate compartment where its concentration increases proportionally. Eor cheese whey and skimmed milk, Hiraoka et al. [165] showed that at the early period of demineralization and CP are initially removed followed by calcium, magnesium, and phosphoms. However, deashing rate of about 60% and 30% for cheese whey and skimmed milk, respectively, had to be reached before Mg started to migrate. In our case, about 22% of demineralization was reached at the end of the ED configuration. 

Whey centrifugation at 1000 g during 5 min (process 1) allowed a 20.8% recovery of cheddar cheese whey initial lipids (Table 21.10). The other components, proteins and lactose were precipitated at a lower rate (1.1% and 0.6%, respectively). A 32.1 % whey lipid precipitation was obtained in process 2 consisting of an electroacidification to reach a pH value of 3.7 before the centrifugation step. This represents a 54% increase of precipitation rate in comparison with process 1, with proteins and lactose precipitation levels quite similar (1.9% and 0.9%, respectively). Demineralization step before electroacidification had only small effect on the precipitation level Similar precipitation levels for lipids and lactose were obtained in comparison with process 2 values except for proteins. Conventional electrodialysis allowed an increase of protein precipitation from 1.9% to 3.3% (Table 21.11). 

Electrodialysis has a number of other large-scale applications and these would include the manufacture of pure sodium chloride for table salt (in Japan, electrodialysis is the principal method, production exceeding 10 ton yr ), the demineralization of cows milk (for baby food), cheese whey and sugar solutions, the removal of excess acid from fruit juice and the isolation of organic acids from reaction streams. 

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