Separation of casein micelles from whey proteins by high shear microfiltration of skim milk using rotating ceramic membranes and organic membranes in a rotating disk module

• Published in: Journal of membrane science 2008-12, Vol.325 (2), p.872-879
• Main Authors: Espina, Valentina S., Jaffrin, Michel Y., Frappart, Matthieu, Ding, Lu-Hui
• Format: Article
• Language: English
• Subjects: Biomechanics; Casein concentration; Dynamic filtration; Mechanics; Milk microfiltration; Physics; α-Lactalbumin and β-lactoglobulin extraction
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2008.09.013

This paper investigates the microfiltration of skim milk in order to separate caseins micelles from two whey proteins, α-lactalbumin (α-La) and β-lactoglobulin (β-Lg), using a modified dynamic filtration pilot (MSD) consisting in 6 ceramic 9-cm diameter membrane disks of 0.2 μm pores, rotating around a shaft inside cylindrical housing. A comparison was made with another dynamic filtration module consisting in a disk rotating near a fixed PVDF 15.5 cm diameter membrane with 0.15 μm pores. Maximum permeate fluxes were 120 L h −1 m −2 with the MSD module at 1930 rpm and at 40 °C, and 210 L h −1 m −2 at 2500 rpm and 45 °C, with the rotating disk module. Casein rejection was around 99% at high speed for both membranes. α-La transmission decreased with increasing transmembrane pressure (TMP) from 75% to 60% for ceramic membranes and from 25% to 10% for the PVDF one. β-Lg transmissions were lower, ranging from 23% to 15% for ceramic membranes and from 20% to 5% for the PVDF one. In a concentration test with the PVDF membrane at 2000 rpm, the flux decayed from 200 L h −1 m −2 at initial concentration to 80 L h −1 m −2 at VRR = 3.2 and 22.1% of the initial α-La mass was recovered in the permeate, against 8.1% for β-Lg. Permeate fluxes in the mass transfer limited regime ( J lim) of the MSD and rotating disk module operated at various speeds were well correlated by the equation J lim = 17.13 V av where V av denoted the disk azimuthal velocity averaged over the membrane area. Measurements of J lim, taken from Ref. [G. Samuelsson, P. Dejlmek, G. Tragardh, M. Paulsson, Minimizing whey protein retention in crossflow microfiltration of skim milk. Int. Dairy J. 7 (1997) 237–242] during MF of skim milk using tubular ceramic membranes at velocities from 1.5 to 8 m s −1 with permeate co-current recirculation were found to obey the same correlation.