Module contents - theoryIntroduction Milk composition Physiochemical features of milk Milk processingDairy products manufacturingDairy microbiologyDairy factory and the environmentQuality assurance of milk & milk products

4. Milk processingCollection and reception of milk Clarification Centrifugal separationMembrane filtration StandardisationHomogenizationPasteurizationSterilizationConcentration

4. Membrane filtration What is Membrane filtration? Principle Why needs Membrane filtration? ImportanceMethods of Membrane filtration? Application

1. What is Membrane Filtration?Filtration of milk through various membranesWith various pore sizes and pressuresPermits for concentrating of milk components Permits for separating of milk components No use of heat Raw milk Milk constituentsComposition ?Composition ?

2. Why needs Membrane Filtration?For separating milk constituents For manufacturing various dairy productsMembrane Processing permits;Impurity separationWater separation Cream separationSkim milk separationWhey protein separation Casein protein separation Lactose separationSpecialized products such as whey powder, casein powder

3. Methods of Membrane Filtration? Principle of membrane processing Reverse of the osmotic pressure Osmotic pressure: When a solution & water separated by a semi-permeable membraneWater move into solutionMake equilibrium This is due to Chemical force caused by concentration gradientKnown as Osmotic pressureReverse osmosis is the principle of membrane processing

Cont; Methods of Membrane Filtration? Osmosis & osmotic pressure

Cont; Methods of Membrane Filtration? Reverse-osmosis

If mechanical force > osmotic pressureWater move against concentration gradient It is Reverse of the osmosis Called Membrane Processing Particles are separated on Their molecular sizeShape Technique used Pressure Specially designed semi-permeable membranesCont; Methods of Membrane Filtration?

Cont; Methods of Membrane Filtration?

According to pressure & pore size; 4 types of MPReverse Osmosis/Hyper-filtration Nano filtrationUltra filtrationDi-filtration MicrofiltrationCont; Methods of Membrane Filtration?

1. Reverse osmosisRO designates a membrane separation processConcentration of milk by removal of waterDriven by a pressure gradientIt is a concentration processMembrane separates water from milk components Membrane pore size is very small Pass only small amounts of solutes Very low molecular weight solutes Use cellulose acetate membranes Heat milk to 40CUse composite membranesHeat milk to 70 to 80C

Cont; Reverse osmosisConcentrate milk solventMembrane pore size m Pressure 30 to 60 bars (700 psi)Collect Permeate Retentate10-4-10-3

Cont; Reverse osmosis

2. Nano filtrationConcentration of organic components By removal of water & mineralsMembrane pore size 10-3-10-2 m -Pressure 20 to 40 bars (470 psi)Membrane materialPolysulfane membranesHeat milk to 50-60C

3. Ultra-filtrationConcentration of large and macro moleculesFatProteinMembrane pore size 10-2-10-1 m Pressure 1 to 10 bars (80 psi)Heat milk to 50-60CLactose & minerals pass into permeateA 50% separation ratiom

Cont; Ultra-filtrationIn the retentate would be 100% of fat100% of protein50% of lactose50% of free minerals

Di-filtrationA modification of ultra-filtrationRetentate further diluted with waterRe-ultra filteredReduce the concentration of soluble permeate componentsIncrease further the concentration of retained components

Cont; Di-filtration

4. Micro-filtration Removal of bacteria & separation of macro moleculesUse larger membrane pore size 10-1-101 m Allow to pass particles from 0.2 to 2 micrometersPressure - < 1 bars (15 psi) Heat milk to 50-60CMF use for making low-heat sterile milk As proteins may pass through but bacteria do not

Cont; Microfiltration flowchartApplication of Microfiltration in pasteurized milk manufacturing

Cont; Methods of Membrane Filtration?

Cont; Methods of Membrane Filtration?

Cont; Methods of Membrane Filtration?

Cont; Membrane filtrations

Spectrum of application of membrane filtration in dairy industry

Batch membrane filtering unit

Batch membrane filtering unit

Cont; Membrane filtering unit

Cont; Membrane filtering unit

Whey manufacturing by membrane filtering

Whey/lactose manufacturing by membrane filtering

DialysisUse the concentration difference as a driving force for separating large particles from small ones in a solution