Effect of changes in ionic composition induced by different diafiltration media on deposited layer properties and separation efficiency in milk protein fractionation by microfiltration

Compositional analysis of dairy side streams and assessment of their applicability as diafiltration media

“…For comparison of calcium effects in relation to other components on filtration, we adjusted the calcium level that was found in hard tap water applied during comparable DF by Reitmaier et al . (2021). The chosen values also represent a good approximation to the maximum amounts detected in the carried out screening of industrial NF permeate samples.…”

“…(2010) and Reitmaier et al . (2021). In brief, filtrations were carried out with a ceramic 23‐channel membrane (ISOFLUX®, 0.14 mm, A = 0.35 m²; TAMI Industries, Nyons, France) at constant pressure conditions (Δp TM = 1.10 5 Pa; τ w = 150 Pa).…”

“…2015; Reitmaier et al . 2021). Ultrafiltration permeate obtained from skim milk can be applied as DF medium to avoid such changes of the milk milieu by preserving the native structure of casein micelles (Kulozik and Kersten 2002).…”

“…This layer generates significant resistance against mass transport towards and through the membrane pores, which impairs filtrate permeation (flux) and the transmission of solutes. In particular, changes in electrostatic interaction between casein micelles and their hydration are known to affect the structure of this deposited layer and the related impact as a secondary membrane in MF of milk (Vetier et al 1988;Bouzid et al 2008;Reitmaier et al 2021). Other studies revealed an altered functionality of the casein fraction after the typically applied DF with deionised water.…”

“…Other studies revealed an altered functionality of the casein fraction after the typically applied DF with deionised water. These changes were related to structural changes of casein micelles induced by the modified milieu in conjunction with the major ion washout, particularly calcium as a structurerelevant component, and pH shift (Ferrer et al 2014;Eshpari et al 2015;Reitmaier et al 2021). Ultrafiltration permeate obtained from skim milk can be applied as DF medium to avoid such changes of the milk milieu by preserving the native structure of casein micelles (Kulozik and Kersten 2002).…”