Sidal Acun

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MICROFILTRATION APPLICATIONS IN DAIRY INDUSTRY

• Sidal Acun
• Yrd. Doç. Dr. MERAL KILIÇ

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Microfiltration

• Sieving process
• The most open or porous in the filtration
  spectrum.

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Microfiltration

• Non-thermal or less thermal improves milk
  quality
• Retentate pore diameter gt membrane pore diameter
• Permeate pore diameter lt membrane pore diameter
  (also named microfiltrate)

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Microfiltration

• Separation of small particles about 0.1 to 10 µm
  size range with operating pressures of 0.050.2
  MPa.

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Microfiltration

• Cross-filtration flow parallel to the membrane
  surface, also named cross flow microfiltration

Cross flow microfiltration
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Microfiltration

• Ceramic membranes strong mechanical resistance
  and wide tolerance to pH (0.3 to 13.5).
• Monotubular and multichannel monoliths

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Ceramic Membrane Element
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Microfiltration

• Pore size bubble point method
• Filters pore size customize the retentate and
  permeate
• Liquid flux Retention of particles or bacteria
  of certain sizes.

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Microfiltration Applications

• Main applications
• Removal of bacteria and spores
• Fat seperation (especially for whey)
• Micellar casein enrichment of the cheesemaking
• Milk protein fractionation

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Removal of Bacteria and Spores

• Reduce the microbial load of raw milk
• 20.000 CFU m/L skim milk - microfiltration - lt
  10 CFU m/L skim milk
• Microfiltration 100 C 2 s Shelf life ranging
  from 6 to 9 months.
• Sensory tests show much beter than UHT milks.

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Removal of enzymes

• if heating effectively kills most of the
  microbial flora, the dead cells remain in the
  milk with their potentially active enzymes that
  with the metabolic activity developed by the
  growth of the remaining thermoduric bacteria,
  will cause alterations of liquid milks during
  storage, thus reducing shelf-life

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Fat Seperation

• Whey defatting seperation of aggregated calcium
  phospolipid complex by MF (0.1 µ m pore size).
• Fractionation of globular milk fat (SG and LG)
  drinking milk, yoghourt, sour cream, butter,
  camembert cheese, fresh cheese.
• E.g. skim milkreference cream (1) MF permeate
  (SG) from raw milk (2)
• Same fat content (17 g.kg-1) 2 is more creamy
  than 1

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Casein enrichment

• Casein enrichment (10 µ m MF) pizza cheese,
  coffee whitener
• Micellar casein enrichment (0.1 µ m) improve
  quality of cheese (camembert)and increase
  capacity of cheese plant.

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Casein enrichment

• Gelation Study
• Skim milk 4 C MF, 0.2 mm, 0.1 mm, or 100 000
  g.mol-1 MWCO
• Permeate 10 000 g.mol-1 MWCO 9 solids
  retentate
• Reduced the caseinwhey protein ratio and
  increased
• the b-caseina-casein ratio
• Formed softer gels that had greater syneresis and
  hydration,
• and lower water holding capacities than skim milk
  gels.

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New-dairy based powder

• Mozarelle cheese
• Combination of MF (0.1 and 0.2 mm) and UF
• Avoid b-lactoglobulin-k-casein complex during
  thermal processing
• Rennet coagulability, melting properties and
  improvements
• Cheesemaking yields were 7.3 1.8 higher (with
  milk powder) in comparison with the control
  cheese (with raw milk)

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Milk protein fractionation

• a-lactalbumin-enrichment for infant formulas
• Ceramic membrane 0.1 µ m
• Process 1. step thermal treatment b -LG
  denaturation (a-LA/b -LG 0.3 to 4)
• 2. step a-LA Microfiltration
• Skim milk microfiltration- low heat milk
  powder, milk proteins concentrates or micellar
  casein powder.

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Transmembrane Pressure

• Membrane inlet pressure cause fouling
• Increasing shear rate dont help
• Recirculating permeate at high speed in the same
  direction as the retentate with same axial
  pressure Uniform Trans-Membrane Process Pressure
  (UTP)

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Conventional UTP
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Disadvantage Fouling

• Concentration of fluid, flow rate, TMP, type of
  membrane material, pore size
• Decrease filtration efficiency
• Native proteins start transforming into denatured
  and aggregated proteins
• Distilled with rinsing wateralkaline solution
• a-Lactalbumin fouling

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Disadvantage Expensive

• Cheese brine purification
• MF in a UTP equipment with a pore size of 1.4 µ m
  or 0.8 µ m
• UTP expensive investment cost

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• The manufacturing cost of MF Cheddar was slightly
  higher than the manufacturing cost of
  conventional Cheddar.
• However, the benefit in net revenue from the use
  of MF was estimated to be higher than the
  difference in manufacturing costs.

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Advantages

• Hygienic safety with minimal heat treatment
• Keeping nutritional and bioactive properties of
  milk components
• Dairy research development without any bias
  (önyargi)
• Efficient cheese-making
• New milk derivatives milk protein and fat
  fractionation

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Microfiltration-Pilot Plants
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