Separation of whey protein-pectin complexes and unbound pectin in technical scale: A feasibility study

Abstract

Whey protein-pectin complexes (WPPC) have the potential to be utilized as a fat replacer. However, following the formation of the whey protein-pectin complexes via thermomechanical treatment, a proportion of pectin remains unbound in the surrounding phase, exhibiting the potential to modify the textural attributes of fat-reduced products and overlapping with the effect of the actual WPPC in the dispersion. Therefore, the separation of unbound pectin from the WPPC was investigated. The addition of 1 mol L⁻¹ CaCl₂ and subsequent centrifugation (4000×g, 10 min) yielded high protein concentrations of approximately 80 % in laboratory scale, while approximately 60 % of the pectin was separated. However, the separation process is only suitable for laboratory scale applications and could not be successfully upscaled to a continuous decanter centrifuge. The microfiltration with diafiltration (1.4 μm, 50 °C, 0.1 MPa) proved effective, yielding approximately 82 % protein in the permeate and separating approximately 80 % of the pectin. The pectin-rich dispersion could be successfully recycled, for a new batch of WPPC even improving the resulting complex size range. The separation of unbound pectin from the WPPC allows for the investigation of the effect of the actual WPPC during product application.