Process efficiency of casein separation from milk using polymeric spiral-wound microfiltration membranes

Abstract

Microfiltration is largely used to separate casein micelles from milk serum proteins (SP) to produce a casein-enriched retentate for cheese making and a permeate enriched in native SP. Skim milk microfiltration is typically performed with ceramic membranes and little information is available about the efficiency of spiral-wound (SW) membranes. We determined the effect of SW membrane pore size (0.1 and 0.2 µm) on milk protein separation in total recirculation mode with a transmembrane pressure gradient to evaluate the separation efficiency of milk proteins and energy consumption after repeated concentration and diafiltration (DF). Results obtained in total recirculation mode demonstrated that pore size diameter had no effect on the permeate flux, but a drastic loss of casein was observed in permeate for the 0.2-µm SW membrane. Concentration-DF experiments (concentration factor of 3.0× with 2 sequential DF) were performed with the optimal 0.1-µm SW membrane. We compared these results to previous data we generated with the 0.1-µm graded permeability (GP) membrane. Whereas casein rejection was similar for both membranes, SP rejection was higher for the 0.1-µm SW membrane (rejection coefficient of 0.75 to 0.79 for the 0.1-µm SW membrane versus 0.46 to 0.49 for the GP membrane). The 0.1-µm SW membrane consumed less energy (0.015-0.024 kWh/kg of permeate collected) than the GP membrane (0.077-0.143 kWh/kg of permeate collected). A techno-economic evaluation led us to conclude that the 0.1-µm SW membranes may represent a better option to concentrate casein for cheese milk; however, the GP membrane has greater permeability and its longer lifetime (about 10 yr) potentially makes it an interesting option.

Integrating Pressure-Driven Membrane Separation Processes to Improve Eco-Efficiency in Cheese Manufacture: A Preliminary Case Study

“…All SM generated at the skimming stage was sent to the membrane separation processes for concentration and diafiltration (DF). The membrane separation processes described in Gavazzi-April et al [ 19 ] was used for scenario A, and the membrane separation processes described in Mercier-Bouchard et al [ 12 ] was used for scenario B. In scenario A, SM was concentrated to a volume concentration factor (VCF) of 3.5 then continuous DF with 2.0 diavolumes (DV) was performed—the diavolume is the ratio of the volume of consumed diluent to the volume of treated retentate [ 20 ].…”

“…In both scenarios, concentration and DF were carried out at 50 °C. For scenario B, the protein rejection coefficients obtained by Mercier-Bouchard et al [ 12 ] were used in the mass balance calculations. In scenario A, and in agreement with El-Gazzar et al [ 9 ], total CN retention was considered.…”

“…Today, UF retentate is gradually being replaced by microfiltration (MF) retentate [ 11 ]. MF membranes of 0.1 µm pore size permit higher whey protein transmission while ensuring casein retention [ 12 ]. In addition, MF at the cheese milk standardization stage could improve the organoleptic qualities (taste and texture) of the cheese produced [ 11 , 13 ].…”

Production of Milk Phospholipid-Enriched Dairy Ingredients

“…The relevant processes with a significant MPL CF include membrane filtration, evaporation and spray drying, SFE, and solvent recovery, the improvement of which offer opportunities to reduce the CF of the final products. For example, 0.1-µm polymeric spiral-wound MF membranes have been used to separate casein from milk, exhibiting a higher energy efficiency at 0.024 (MF) and 0.015 (DF) kWh/kg permeate than that of graded permeability membrane (0.143 and 0.077 kWh/kg permeate for MF and DF, respectively [110]. Furthermore, permeate flux, volume concentration ratio, transmembrane pressure, and temperature all had an impact on the energy efficiency of membrane UF, ranging from 0.26-0.33 kWh/kg retentate [116].…”

“…BMC, BM, concentrate; MPLs, milk phospholipids; C6, hexane; DME, dimethyl ether; SFE, supercritical fluid extraction; UF/DF, ultra/dia-filtration; CF, carbon footprint. Membrane filtration power consumption: 1.486 kWh/kg products[110]; Canada power CF factor: 0.1567 kg CO 2 /kWh[111]; CF of reusable solvents (DME, hexane and ethanol): 0.16 kg CO 2 /kg solvent; reused acetone CF: 0.42 kg CO 2 /kg solvent[112]; DME CF 1.01 kg/kg; 84% reuse[113]; baseline of BM: 1.1 kg CO 2 /kg BMP[45]; SFE CO 2 reuse 95%[114]; SFE CO 2 /DME power cost estimation 100 kWh/kg extract[115].…”