Whey protein curves

The separation of dairy proteins by CE has been generally carried out by CZE and has been exhaustively covered in several review papers, - - thus Table 30.8 only presents the key methodologies that offer the reader an overview of their most distinctive features. Basically, dairy protein analysis has been performed in whole milk for the simultaneous determination of caseins and whey proteins, or in fractions isolated from milk after casein precipitation. The first approach being used when the quantitative determination of the major proteins is required for the calculation of casein/whey protein ratios or for authentication purposes where an analysis of the whole protein profile is required. In both cases, accurate quantitative data must be derived. However, few studies have addressed the analysis of both groups of proteins in a single run by presenting quantitative data based on calibration curves constructed with analytical standards and good recovery of all proteins from milk samples. 

Fig. 4.16 Left panel , scattered intensity as a function of the wave vector 2 of a dispersion of unmixing whey protein colloids R 27 nm) mixed with exocellular polysaccharides Rg = 86 nm q = 3.2) [19]. The time after mixing is indicated (in hours). Right panel , log-log plot of the characteristic length scale A = 2n/Q,n obtained from the /(2) curves as a function of time. The diffusive growth (4.41) and viscous hydrodynamic growth (4.42) scaling regimes are indicated as straight lines...

Thuwapanichayanan et al. (2012) determined the drying curves of banana foams produced with aid from one of three foaming agents, namely egg albumin (EA), soy protein isolate (SPI) and whey protein concentrate (WPG) (Fig. 6.19). The results of these studies showed a strong effect of surfactant type on drying rate due to the development of different foam structures, while the exponential decrease in moisture content with time proved that the drying process of banana foams was controlled by internal diffusion. 

Fig. 6.19 D ing curves of banana foams with different foaming additives. Egg albumin (EA), soy protein isolate (SPI), and whey protein concentrate (WPC). Adapted from Thuwapanichayanan etal. (2012).

Set up 12 test tubes (10 X 100 mm, colorimetric tubes) and add water and proteins according to the top three rows of Table E4.2 Tube 1 is used as a blank and tubes 2 through 6 are for construction of a standard calibration curve. Tubes 7 to 10 are duplicates of two different concentrations of the isolated a-lactalbumin solution, and tubes 11 and 12 are two concentrations of whey. Water is added to give a final volume of 1 0 mL m each tube Add 5,0 mL of dilute Bradford dye reagent to each tube and mix well by gentle inversion After a period of at least 5 minutes, read for each tube, using tube 1 as a blank The tubes should be read within an hour after adding the... 

---