LAUSR

Abstract The suitability of ultrafiltered skim milk microfiltration permeate, concentrated ‘ideal whey’, ( W con ) as protein source in comparison to whey protein isolate (WPI) for thermomechanical whey protein-pectin complex (WPPC) formation with a scraped-surface heat exchanger on laboratory scale was investigated. Protein concentrations were between clow = 0.7% and chigh = 5.20% (protein:pectin = 5:1) and representative shear rates γ ˙ rep ranged from 150 to 675 s−1. WPPCs were analyzed by intrinsic fluorescence spectroscopy, static light scattering, light microscopy, and apparent particle binding energies σ * were calculated. With increasing γ ˙ rep WPPC size decreased. An influence of protein source on complex assembly was found as σ * was about four times higher whilst using W con instead of WPI (at equal c). Finally, W con (at γ ˙ rep ≥ 500 s−1) is suitable to obtain WPPCs with desired properties (primary complexes with d90,3  μ m) for applications as fat-replacers in dairy matrices.