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Whey protein concentrates and isolates are used as food additives in the production of a variety of baked goods, dairy products, meats, and beverages (Cayot and Lorient, 1997). However, the lack of consistency in the gross composition and functionality of these products has limited their acceptance by the food processing industry (Morr and Ha, 1993). Commercial whey protein concentrates can also develop a stale off-flavor due to the presence of lipid and protein impurities (Morr and Ha, 1991). In addition, the unique nutritional, therapeutic, and functional characteristics of the individual whey proteins are largely unrealized in these whey products due to interactions between components and degradation during processing. There has thus been considerable commercial interest in the production of individual (purified) whey proteins with well-characterized functional and biological properties. Today various technologies of ranging complexity, reliability and cost have been developed to forestall pollution by waste whey and to find uses for this by-product. These treatments very often involve separating the major components, first of all to eliminate water. The extraction of lactose, proteins and salts affords various. Whey proteins were originally isolated using various techniques of precipitation, but nowadays, membrane technologies and chromatography are used or techniques of precipitation with complexing agents (Scopes 1988). Zydney (1998) showed that it was possible to fractionate the constituents of whey of whey using a system of membranes and changes in the pH and ionic strength of solutions. This technique may have applications at a large scale if appropriate conditions are used.

Membrane technology is finding interesting applications in the water industry. Developments in membrane technology have created the opportunity for an entirely new approach to cheese technology. Membrane processes have some advantages that make the membrane treatment attractive such as continuous operation, no pollution of the environment, small space requirements, suitable for high salt contents, easy transportation, simple operation, no civil construction necessary at the site and reduced cost with technological environments (Koyuncu et. al., 2000). Membrane systems are used extensively throughout the dairy industry to control the protein, fat,

and lactose content of a variety of products. These membrane processes have been successful because they can be effectively and economically implemented at the large scale required for most dairy applications. Ultrafiltration/diafiltration (UF/DF) has been used to separate whey protein from lactose sugar and other components in the whey. Whey protein has found a good market as a food additive or protein supplement. The permeate stream after UF/DF is mainly composed of lactose, salts, and a lot of water, which can be dried to produce whey permeate powder (deproteinized whey). Drying of whey permeate need to remove large amount of water, which is an energy-intensive process. The lactose sugar fraction in cheese whey can be used to produce value-added products such as lactic acid, ethyl alcohol, and methane gas or to grow cells for an antibacterial compound, but this is not currently in full-scale production. Ultra filtration (UF) uses polymeric or ceramic membranes which are fully retentive to the whey proteins to remove lactose and minerals, yielding a retentate stream that can be further processed by evaporation and spray drying. The net result is a whey protein concentrate that is around 60% protein by weight, making this an attractive animal feed supplement. The lactose and mineral content in the whey protein concentrate can be further reduced using a subsequent diafiltration (DF) in which deionized water is continually added to the retentate while lactose and minerals are simultaneously removed in the filtrate. This combined UF- DF yields a high value retentate (approximately 85% protein) which can be added to a number of dairy products (e.g., yoghurt or cottage cheese) or used in a variety of beverages, processed meats, and baby foods.

In this context, today’s work aimed to used whey, a by-product of the cheese and casein production, by transforming it into products with high nutritional and functional values for use in the food and pharmaceutical industries.

5.1 Recovery Products

The following individual whey proteins, in order of decreasing concentration in whey are potential candidates for ingredients in functional foods.

• Beta-lactoglobulin: This protein comprises 50 to 60% of total whey protein. Betalactoglobulin binds retinol (provitamin A) and has been proposed to be a transport protein for retinol (Harper, 2000). Beta-lactoglobulin is a rich source of the essential amino acid cysteine, which is important for the synthesis of glutathione.

• Alpha-lactalbumin: This protein accounts for about 25% of total whey protein. In the mammary gland, alpha-lactalbumin acts as the coenzyme in the biosynthesis of lactose. In some countries, alpha-lactalbumin is used commercially in infant formulas to make the formula more similar to human milk. In addition, alpha lactalbumin may enhance immunity and reduce risk of some cancers (German et al., 2000, Harper, 2000). Because alpha-lactalbumin is a good source of branched chain amino acids, it may also be used in sports nutrition products (German et al., 2000). • Immunoglobulins. The immunoglobulins in bovine whey (and colostrum) include IgA and secretory IgA; IgG1, IgG2, and IgG fragments; IgM; and IgE. This group of whey proteins provides passive immunity for infants and may stimulate immune function in adults (German et al., 2000, Harper, 2000).

• Bovine serum albumin. Bovine serum albumin binds fatty acids and other small molecules. Because of its high cysteine content, bovine serum albumin may be an important source for the production of glutathione in the liver.

• Lactoferrin. This iron-binding whey protein appears to have multiple biological functions. These include iron transport, antibacterial and toxin binding properties, promotion of cell growth, stimulation of the growth of beneficial intestinal bacteria (e.g., Bifidobacteria), antioxidant properties, and immunomodulating and antiinflammatory effects (German et al., 2000, Harper, 2000). Lactoferrin is used in infant formula in some countries to provide a formula similar in protein composition to human milk and to enhance iron absorption without causing constipation. Many of the proposed biological activities of lactoferrin are related to its iron-binding properties, although non-iron-binding activities have also been demonstrated (Schaafsma and Steijns, 2000; German et al., 2000; Schupbach et al., 1996).

• Lactoperoxidase. This milk enzyme is a natural antimicrobial agent with a variety of potential applications including use in dental products such as toothpaste and mouth rinses to inhibit the development of dental caries (German et al., 2000, Harper, 2000).

• Other Peptides. Whey contains peptides both present in milk and formed by the hydrolysis of various milk constituents, including casein. Glycomacropeptide (GMP), perhaps the most notable, is produced by the action of the enzyme, chymosin, on kcasein (German et al., 2000, Harper, 2000). Beneficial biological

roles attributed to GMP or peptides derived from it include stimulation of cholecystokinin (a hormone regulating energy and food intake) release from intestinal cells, inhibition of platelet aggregation, and support of beneficial intestinal bacteria (i.e., Bifidobacteria) (German et al., 2000, Harper, 2000). In an in vitro study, GMP prevented adhesion of cariogenic bacteria to tooth surfaces, leading researchers to speculate that GMP may reduce dental caries (Schupbach et al., 1996). Because GMP lacks the amino acid phenylalanine, GMP has potential use as an ingredient in foods for patients with phenylketonuria (PKU). These patients are unable to metabolize phenylalanine and therefore must be provided diets free of phenylalanine (Harper, 2000).Peptides derived from betalactoglobulin in whey have antihypertensive activity in spontaneously hypertensive rats (Abubakar et al. 1998). Other peptides such as lactoferricin, which is derived from lactoferrin, exhibit antimicrobial activity (Schaafsma and Steijns, 2000).

They are known to be involved in antioxidant activity, anticarciogenic effects, immunomodulation, passive immunity, anti-microbial effects, binding of toxins, promotion of cell growth, platelet binding, anti-inflammatory and anti-hypertensive actions.

Different whey proteins, when solely obtained, can be of great interest for re-use. Fractionation of above mentioned whey proteins, especially beta-lactoglobulin and alphalactalbumin can be achieved by membrane processes in high purity to be specifically used in different industries such as pharmaceutical industry.