Free Access
| Issue |
Lait
Volume 80, Number 1, January-February 2000
New applications of membrane technology in the dairy industry
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|---|---|---|
| Page(s) | 121 - 127 | |
| DOI | https://doi.org/10.1051/lait:2000113 | |
DOI: 10.1051/lait:2000113
Lait 80 (2000) 121-127
Shear separation: a promising method for protein fractionation
Mark F. Hurwitz
,
John D. Brantley
Process Equipment Development Department, Pall Corporation,
Cortland, New York, 13045, USA
10 Deer Drive, Sound Beach NY, 11789, USA
Abstract:
Shear Separation is a method of separating macromolecules suspended in a fluid by inducing hydrodynamic
forces that depend on size. The forces are produced in the laminar sub-layer of a turbulent shear boundary
layer adjacent to a porous membrane. The suspended particles are lifted away from the porous membrane,
against the drag of the permeate flow, by the viscous part of the shear stress. We have found that the
transmission rate of a protein through the membrane depends on the shear rate, the permeate rate, the
protein size, and the protein shape, even when the pore size of the membrane is substantially larger than
the largest of the proteins. As a result, this is a size and shape dependent separation of the
macromolecules. The membrane functions as a surface upon which an extremely high shear laminar sub-layer
at the membrane surface may be generated. The effect has been demonstrated on the bench scale with clean
mixtures of cytochrome C and bovine serum albumin. The separation can be observed with membranes rated
approximately
molecular weight cut off (MWCO) or less. Using this technique,
milk serum containing BSA and smaller proteins without fats, caseins or immunoglobulins has been produced
from skimmed milk. In addition, the milk serum has been fractionated with transmission fractions of 18%
for BSA, 33% for 
-lactoglobulin, and 62% for 
-lactalbumin.
molecular weight cut off (MWCO) or less. Using this technique,
milk serum containing BSA and smaller proteins without fats, caseins or immunoglobulins has been produced
from skimmed milk. In addition, the milk serum has been fractionated with transmission fractions of 18%
for BSA, 33% for -lactoglobulin, and 62% for -lactalbumin.
shear separation / fractionation / dairy / ultra-filtration / protein
Correspondence and reprints: M.-F. Hurwitz
mark-hurwitz@pall.com
Copyright INRA, EDP Sciences