Whey Protein Concentrate,

Table 5. Whey Protein Concentrate Compositions from Different Sources ...

The consumption of dairy products plays a significant role in providing high-quality protein, vitamins, minerals, and other bioactive compounds to the American diet. Dairy products are consumed fresh in the United States in the form of fluid milk, cheese, yogurt, butter, and ice cream. Dried and condensed products such as nonfat dried milk, whey, whey protein concentrates, and isolates are also produced which are used as ingredients to boost the nutritional and functional properties of a host of other food... 

WPC80 whey protein concentrate, 80% protein. WLAC whey lactalbumin. WPI whey protein isolate number reported is mean of three samples. Means with different letters within a column are significantly (p < 0.05) different. 

FIGURE 5.6 Solubility of texturized dairy protein products extruded at different temperatures, 25 (control), 50, 75, and 100 C Nonfat dried milk (NDM) whey protein concentrate (WPC80), containing 80% protein and whey protein isolate (WPl), containing 95% protein (Onwulata et at, 2003a). 

Kim, C. H. and Maga, J. A. (1987). Properties of extruded whey protein concentrate and cereal flour blends. LWT Food Sci. Technol. 20,311-318. 

Manoi, K. and Rizvi, S. S. H. (2008). Rheological characterizations of texturized whey protein concentrate-based powders produced by reactive supercritical fluid extrusion. Food Res. Int. 41, 786-796. 

Matthey, F. P. and Hanna, M. A. (1997). Physical and functional properties of twin-screw extruded whey protein concentrate-corn starch blends. LWT Food Sci. Technol. 30,359-366. 

Morr, C. V. and Ha, E. Y. (1993). Whey protein concentrates and isolates Processing and functional properties. Grit. Rev. Food Sci. Nutr. 33, 431-476. 

Nalesnik, C., Onwulata, C., Tunick, M., Phillips, J., and Tomasula, P. (2007). The effects of drying on the properties of extruded whey protein concentrates and isolates. /. Food Eng. 80, 688-694. 

Nutrition and Food Management 236 Lecture Whey Protein Concentrates. Oregon State University, http //class.fst.ohio-state.edu/FST822/lectures/WPC.htm... 

Ye, A., Singh, H. (2000b). Influence of calcium chloride addition on the properties of emulsions stabilized by whey protein concentrate. Food Hydrocolloids, 14, 337-346. 

Damianou, K., Kiosseoglou, V. (2006). Stability of emulsions containing a whey protein concentrate obtained from milk serum through carboxymethylcellulose complexation. Food Hydrocolloids, 20, 793-799. 

Procedures and conditions for whey protein concentrate (WPC) gel formation have been described (14,15,16,25). Several commer-... 

Table III. Dialysis effect on gel characteristics of 10% protein dispersions of whey protein concentrate (WPG) heated at 100 C for 15 rain.

Proteins of egg white denature more rapidly than those of whey protein concentrate (13, 34). However, isolated p-lactoglobulin from the whey concentrate was more susceptible to surface denaturation than egg white ovalbumin. These data suggest that whey contains substances that protect the proteins from surface denaturation and may account for the lower stability of whey protein concentrate foams than those of egg white protein. A balance between the disaggregation effect of select pH values and the tendency toward greater aggregation of proteins at higher heating temperatures were correlated closely with maximum foam stability (13, 15). 

Milk protein products. As indicated in Table 1, the food industry is placing major emphasis on the production and utilization of milk protein products in a wide variety of formulated food products (20,21,22). Although nonfat dry milk (NFDM) and whey powder are major milk protein ingredients in formulated foods, casein and whey protein concentrates, which contain their proteins in a more highly concentrated and functional form, are essential for certain food product applications, such as those products that require the proteins as an emulsifier agent. Additional details on the processing methods and conditions used to produce the various milk protein products are available (23). 

Whey protein concentrates (WPC) are produced by a variety of processing treatments to remove both lactose and minerals (20) as indicated in Figure 5. Even though it would be highly desireable to remove most of the lactose and minerals in these processes, it is not practical from an economic standpoint and thus most of these products only range in protein content from 35 to 50 %.The major objective of most of these processes is to produce a WPC with minimal protein denaturation in order to obtain a product with maximum protein solubility and functionality. However, from a practical consideration this objective is not readily obtainable, and thus most WPC products commercially available exhibit variable whey protein denaturation and functionality (20). 

Figure 5. Process flowchart jor preparing whey protein concentrate (20)...

Whey protein concentrates (WPC), which are relatively new forms of milk protein products available for emulsification uses, have also been studied (4,28,29). WPC products prepared by gel filtration, ultrafiltration, metaphosphate precipitation and carboxymethyl cellulose precipitation all exhibited inferior emulsification properties compared to caseinate, both in model systems and in a simulated whipped topping formulation (2. However, additional work is proceeding on this topic and it is expected that WPC will be found to be capable of providing reasonable functionality in the emulsification area, especially if proper processing conditions are followed to minimize protein denaturation during their production. Such adverse effects on the functionality of WPC are undoubtedly due to their Irreversible interaction during heating processes which impair their ability to dissociate and unfold at the emulsion interface in order to function as an emulsifier (22). 

One of the important developments in dairy technology in recent years has been the fractionation of milk into its principal constituents, e.g. lactose, milk fat fractions and milk protein products (caseins, caseinates, whey protein concentrates, whey protein isolates, mainly for use as functional proteins but more recently as nutraceuticals , i.e. proteins for specific physiological and/or nutritional functions, e.g. lactotransferrin, immunoglobulins). 

Whey powders, demineralized whey powders, whey protein concentrates, whey protein isolates, individual whey proteins, whey protein hydrolysates, neutraceuticals Lactose and lactose derivatives Fresh cheeses and cheese-based products Functional applications, e.g. coffee creamers, meat extenders nutritional applications Whey powders, demineralized whey powders, whey protein concentrates, whey protein isolates, individual whey proteins, whey protein hydrolysates, neutraceuticals Various fermented milk products, e.g. yoghurt, buttermilk, acidophilus milk, bioyoghurt... 

Industrially, whey proteins are prepared by ultrafiltration or diafiltration of whey (to remove lactose and salts), followed by spray drying these products, referred to as whey protein concentrates, contain 30-80% protein. 

Ultrafiltration/diafiltration of acid or rennet whey to remove varying amounts of lactose, and spray-drying to produce whey protein concentrates (30-80% protein). 

The sorption behaviour of a number of dairy products is known (Kinsella and Fox, 1986). Generally, whey powders exhibit sigmoidal sorption isotherms, although the characteristics of the isotherm are influenced by the composition and history of the sample. Examples of sorption isotherms for whey protein concentrate (WPC), dialysed WPC and its dialysate (principally lactose) are shown in Figure 7.13. At low aw values, sorption is due mainly to the proteins present. A sharp decrease is observed in the sorption isotherm of lactose at aw values between 0.35 and 0.50 (e.g. Figure 7.13). This sudden decrease in water sorption can be explained by the crystallization of amorphous lactose in the a-form, which contains one mole of water of crystallization per mole. Above aw values of about 0.6, water sorption is principally influenced by small molecular weight components (Figure 7.13). 

Figure 7.13 Water vapour sorption by whey protein concentrate (A), dialysed whey protein concentrate (B) and dialysate (lactose) from whey protein concentrate (C) (from Kinsella and...

Sktm-milk powder Whey powder Whey protein concentrate Coprecipitates Previously processed cheese... 

In addition to the general decrease in viscosity with increasing temperature, heating milk can also influence its rheology by heat-induced denatura-tion of cryoglobulins and/or other whey proteins. Concentration of milk, e.g. by ultrafiltration, prior to heating results in a greater increase in f/app than in milk heated before concentration. 

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. ... 

Forsum, E., Hambraeus, L. and Siddiqi, I. H. 1974. Large-scale fractionation of whey protein concentrates. J. Dairy Sci. 57, 659-664. 

Proteins that remain in whey after removing casein from milk are recovered as whey protein concentrates by precipitation with added polyphosphate or other polyvalent anionic compounds, ultrafiltration, ion exchange adsorption, gel filtration, or a combined acid and heat precipitation process. Whey protein concentrates are also manufactured by a combined process involving electrodialysis, concentration, lactose crystallization, and drying (Richert 1975 Morr 1979 Marshall 1982 Anon. 1982 Muller 1982B). 

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