Whey Protein Recovery

Cheese Whey Protein Recovery. Perhaps the best publicized application for UF is in cheese whey processing. Cheese whey is the supernatant liquid produced in the cheese making process after precipitation of casein from milk. There are two types of whey sweet whey (minimum pH of 5.6) results when rennet-type enzymes are used to coagulate the casein to form Gouda and Cheddar cheeses  

The lactose is the prime contributor to the high BOD of the whey stream (35,000 to 55,000 ppm). The 150 billion pounds of cheese whey produced each year has become a significant pollution problem choking out aquatic life in 

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). 

First Stage Second Stage Feed Stream Permeate Permeate 

Unfortunately, lactose cannot demand a price sufficient to pay for the second stage. Current world production of lactose is less than 5% of that in whey and future demand shows no significant increase. 

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Ayers JS and Petersen MJ. Whey protein recovery using a range of novel ion exchangers. NZ J. Dairy Sci. Technol. 1985 20 129-142. 

Membrane-retained components are collectively called concentrate or retentate. Materials permeating the membrane are called filtrate, ultrafiltrate, or permeate. It is the objective of ultrafiltration to recover or concentrate particular species in the retentate (eg, latex concentration, pigment recovery, protein recovery from cheese and casein wheys, and concentration of proteins for biopharmaceuticals) or to produce a purified permeate (eg, sewage treatment, production of sterile water or antibiotics, etc). Diafiltration is a specific ultrafiltration process in which the retentate is further purified or the permeable sohds are extracted further by the addition of water or, in the case of proteins, buffer to the retentate. 

Lan, Q., Bassi. A., Zhu, J.X. and Margaritis, A., Continuous protein recovery from whey using liquid-solid circulating fluidized bed ion-exchange extraction, Biotech. Bioeng., 78 (2002) 157-163. 

Even though liquid whey has been successfully commercialized in the form of alcoholic and nonalcoholic beverages, these are still a rarity in most countries. Most whey is converted to whey solids as ingredients for human food or animal feeds by traditional processes such as spray drying, roller drying, concentration to semisolid feed blocks, or production of sweetened condensed whey. Jelen (1979) reported other traditionally established processes including lactose crystallization from untreated or modified whey, production of heat-denatured whey protein concentrate, or recovery of milk fat from whey cheese in whey butter. ... 

Hidalgo, J., Krusman, J. and Bahren, H. U. 1973. Recovery of whey proteins with sodium hexametaphosphate. J. Dairy Sci. 56, 988-993. 

Filtration of small (nano) particles from solvent using a filter with extremely small pores (0.001-0.010 micron) finer than ultrafiltration, not as fine as reverse osmosis. Used for the removal of viruses from plasma protein products. See Yaroshchuk, A.E., Dielectric exclusion of ions from membranes, Adv. Colloid Interface Sci. 85,193-230,2000 Rossano, R., D Elia, A., and Riccio, R, One-step separation from lactose recovery and purification of major cheese-whey proteins by hydroxyapatite — a flexible... 

Bird MR and Bartlett M. Measuring and modelling flux recovery during the chemical cleaning of MF membranes for the processing of whey protein concentrate. J. Food Eng. 2002 53 143-152. 

These results demonstrated the feasibility of EDBM for whey protein separation and the influence of the initial protein concentration on the purity and yield of the separated fraction. At 5% WPI initial concentration, this technology allowed the separation of 98% pure (3-lg fraction with a 44% recovery yield, while at 10% WPI initial concentration a (3-lg-enriched fraction was produced containing 97.3% of (3-lg and 2.7% a-la, for a 98% total protein purity. The 10% protein concentration seems to be the best level for electrodialytic parameters and protein recovery. Furthermore, EDBM of a 10% WPI solution, by precipitation of 53.4% of the (3-lg, allowed the production of an a-la-enriched fraction in the supernatant. Since the best pH to precipitate (3-lg was demonstrated to be pH 4.65 [21], and that the protein yield increases with an increase in initial protein concentration in the solution, it was expected that electroacidilication of a 20% WPI solution to pH 4.65 would allow the highest precipitation yield. However, the limiting factor of such a process at 20% was the low conductivity of the protein solution at pH 5.0. 

Microfiltration of Milk and Recovery of Native Whey Proteins.642... 

Microfiltration processing for clarification and defatting of cheese whey, for selective separation and concentration of micellar caseins from milk for various purposes, for fractionation of caseins and their peptides, for recovery of native whey proteins from milk, for gentle sterilization of milk to produce extended shelf fife liquid milk and cheese milk, for fractionation of globular milk fat and its components, for the reduction of microorganisms in cheese brine, and for the removal of colloidal particles in membrane cleaning solutions. 

Ultrafiltration processing for whey proteins concentration and fractionation, for recovery of lactose from milk and whey, for total milk protein concentration for the production of milk protein concentrate (MFC) or nulk protein isolate (MPl), for milk standardization for continuous mechanized manufacture of cheese and other fermented products, and for production of high-solids milk base for dried milk production. 

With the objective of increasing calcium and lactose content of MF retentate in addition to micellar casein whUe maximizing whey protein depletion. Nelson and Barbano [114] developed a multistage MF process that removed -95% of whey protein from skim milk. They reported that the MF retentate produced from this process contained soluble minerals, NPN, and lactose similar to the original milk. This was accomplished by using the permeate from the UF of the MF permeate to diafilter the MF retentate after achieving a concentration factor of 3 in the MF. Aside from the recovery of native micellar caseins, they showed that the process enabled the production of whey protein stream (UF retentate) with protein content similar to that of commercial WPC. 

Because of very high biological value and absence of antinutritional factors, except for some allergenic activity, milk proteins have found various application in formulated foods and as meat extenders. Initially only the caseins were used, but recently the recovery of whey proteins and their fractions was made economically feasible. 

Interactions between protein and polyelectrolytes have been used to fractionate protein solutions (1-3), recover whey proteins (1, 3-6) and isolate serum glycoproteins (7) and recA protein (8). If the potential for protein recovery and purification from aqueous solution by precipitation with polyelectrolytes is to be fully exploited, several factors must be evaluated. The efficacy of the protein precipitation as well as the characteristics of the resulting precipitates depend on several variables. 

Selective precipitation of whey protein has been accomplished by pH shifts of protein/polyelectrolyte mixtures. Beta-lactoglobulin is almost quantitatively precipitated by CMC at pH 4.0 but very little a-lactalbumin is precipitated at this pH. Following removal of jj-lactoglobulin, the pH is reduced to 3.2 to allow recovery of a-lactalbumin (1). 

The development of commercial ultrafiltration equipment has made recovery of the whey proteins economically feasible, and a number of uses for the remaining lactose (the principal BOD source)... 

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