Concentrated whey as protein source for thermally stabilized whey protein-pectin complexes

Abstract

The suitability of ultrafiltered skim milk microfiltration permeate, concentrated ‘ideal whey’, (Wcon) 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 Wcon instead of WPI (at equal c). Finally, Wcon (at γ˙rep≥ 500 s−1) is suitable to obtain WPPCs with desired properties (primary complexes with d90,3 < 10 μm) for applications as fat-replacers in dairy matrices.