Whipping expansion

Whipping Expansion. The method of Eldridge et al. (15) was used with slight modifications to determine the percentage of expansion ... 

Whipping Expansion. Figure 8 shows that the whipping properties are very much improved after treatment with Alcalase. The general picture resembles that of emulsifying capacity which is not unexpected because the mechanism behind the two phenomena is more or less the same. In the case of whipping, the air is considered as the hydrophobic medium. 

The whipping expansion was determined by 4 minutes whip of a solution having 3% protein ( ). Figure 4 shows whipping expansion versus DH for ultrafiltered and acid-precipitated soy proteins modified by Alcalase. Similar results have also been found for ultrafiltered and acid-precipitated proteins from faba beans (Vicia faba) (Sejr Olsen, unpublished results). 

The final protein products were analysed and evaluated for their whipping expansion, foam stability and in the case of the DH-6%-products for baking performance in a meringue batter as well. The analytical procedures are described below. 

If the combinations I, II and IV are compared with respect to the yields and functional properties, it appears that both whipping expansion and foam stability are highest at the high DH-value. However, due to higher content of low molecular peptides at the high DH-value, the overall protein (N x 6.25) yields are lower. The processes have to be evaluated more thoroughly in order to find a compromise between the protein yields and the functionality wanted. 

Figure 6. Whipping expansion vs. the number of free NH groups for highly functional soy protein ultrafiltered after hydrolysis...

Kinsella (13, 14) summarized present thinking on foam formation of protein solutions. When an aqueous suspension of protein ingredient (for example, flour, concentrate, or isolate) is agitated by whipping or aeration processes, it will encapsulate air into droplets or bubbles that are surrounded by a liquid film. The film consists of denatured protein that lowers the interfacial tension between air and water, facilitating deformation of the liquid and expansion against its surface tension. 

Instant whipped cream is based on the same foam-stabilizing principles but is packaged as a liquid (emulsion) and a gas under very high pressure in an aerosol can (see the footnote to Section 15.5). When the can s valve is released, the tremendous gas expansion through a fine orifice drives the formation of the foam topping. In non-dairy instant whipped topping products the cream is replaced by vegetable oil, water, and a number of emulsifiers, stabilizers, and preservative. 

Fig. 3. It is believed that the upstream viscoelastic whipping resulted in flow instability downstream of the contraction. This flow instability, together with the expansion flow effects of the mainstream, promoted effective mixing downstream. The mixing efficiency was found to be 22 % when upstream of the contraction and improved significantly to 68 % when downstream of the contraction.

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