Growing Demand for Functionally Superior Protein Gives

¶ … growing demand for functionally superior protein gives us an excellent opportunity for endeavoring to improve the foaming properties of whey protein isolates (WPI) is dairy companies. There are several factors that effect the foaming properties of whey protein isolate.

These include the following: internal elements amino acid composition and sequence other structures inherent to the WPI hydrophobic / hydrophilic character of the WPI surface the overall charge and the distribution of the charge the flexibility or rigidity of the protein itself External elements ionic strength ph (i..e level of the acidity or basicity of the solution) temperature its interaction with other food components Reviews of attempted improvements of the WPI show that they have been affected by isolation (Ludwig et al., 1995).

When Morr and Ha (1993) studied the foaming properties of WPI, he distinguished them into four kinds and found differences. His four kinds were (a) pasteurized acid casein whey (b) non-pasteurized acid casein whey © Cheddar cheese whey using ultra filtration and (d) Cheddar cheese using spray-drying process. The differences that he discovered in the foaming properties, he concluded, were due to the differences in their protein and non-protein structure as well as to differences in the structural state of the protein.

There are also studies (reviewed by Zhu & Damodaran, 1994) that show that WPI boiled at moderate temperature shows better and improved foaming than it does at intense temperatures. The studies were condensed and brief with no explanation given for the outcome. Rather, it seems to have been intuitively understood that changes seen were due to the internal and external characteristics of the WPI. In 1994, Zhu & Damodaran contrasted testing whey protein isolates at high (90.C0 and moderate (70.C) temperatures.

They also studied changes in physiochemical properties as well as in surface hydrophibicity, ph content, hydrodynamic properties, solubility profile, and other content by differing the percentage of WPI studied in each group. One group contained 9% WPI, the other group contained 5%. Zhu & Damodaran discovered that whilst the WPI element that was heated at 70.C exhibited marked improvement in foaming properties and internal structure (it exhibited better foamability and foam stability), that heated at 90.C did not exhibit significant changes in secondary content whatsoever. On the contrary, the surface hydrophbicity decreased.

The quantity and quality of faomabiltiy, the researchers concluded, was also attributable to the percentage of WPI used, more specifically by the ratio of polymer to monomer protein that was present in the WPI species. When there was more equal distribution at 5% than at 9%, the WPI showed more foamabiltiy and stable foam quality. Zhu & Damodaran studied two constituents simultaneously -- heating rate and ratio of polymer to monomer. The two elements could have been confounded.

This study is interested in seeing firstly whether there is a difference between heating rates alone, leaving the proportion of monomer to polymer constant throughout, and whether improved foamabiltiy and stable foam can be found at different heating rates. Secondly, whilst Zhu & Damodaran jumped to the 70.C level without assessing a lower level, this study would like to take 3 disparate elves -- 50.C, 70.C, and 90.C, and see whether contrast in foamability can be observed between each one.

Research Intent: To heat a certain proportion (5%) of whey protein isolate (WPI) at a specific temperature (50.C).