Dairy Applications

Fat Removal

Whey Protein Isolate (WPI) is a high-quality product requiring protein levels of more than 90% in the total solids. Because the whey proteins are concentrated to a very high level, removal of fat is required to achieve these final target protein concentrations, in addition to the pretreatment separation, which leaves 0.05% fat in the whey. TRISEP® microfiltration membrane separates large suspended solids such as colloids, particulates, fat and bacteria while allowing sugars, whey proteins, salts and low molecular weight molecules pass to through the membrane. Since fat globules are about the same physical size as bacteria cells, microfiltration easily and successfully removes fat from these feed streams. This product is available using feed spacers of various thicknesses to account for the total solids content. For more information or questions, please contact MICRODYN-NADIR.

TurboClean microfiltration elements are USDA-accepted sanitary products that comply with 3-A Sanitary Standard 45-03 and are widely used in dairy and other process applications.

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Cheese Brine Clarification

Good quality brine is often used to “salt” and cure many different varieties of cheese, typically soft cheeses that still contain a certain amount of whey proteins. The brine and curing process is essential to cheese flavor, taste, rind and the appearance of the cheese.

To maintain its efficacy in curing the cheese and inhibiting bacterial growth, the chemical and microbiological composition of the cheese brine is kept within strict limits. Over time, however, the brine becomes enriched with fats, proteins and lactose and may contain undesired microorganisms (i.e. bacteria, spores, yeast and mold). For example, when submerged into a salty brine bath, the salt in the cheese tends to find an osmotic balance with the brine. This draws some of the whey (which contains whey protein) out from the cheese and into the brine bath. After a number of circulations through the brine bath, though, a balance between the salt and whey protein is established and very little whey protein (and sometimes casein) is washed into the brine. Eventually, the heavily contaminated brine must be replaced with a new brine solution or treated for reuse.

Disposal of cheese brine is very expensive due to the high content of salt. Although many traditional brine treatment methods exist (i.e. heat treatment, kieselguhr filtration or diatomaceous earth, UV treatment or even the addition of preservatives), membrane filtration has proven to be a superior technology for the sanitation of cheese brine as it physically removes the undesired microorganisms, dead cells and physical contaminants from the brine without making a significant change to its chemical composition. The benefits of using a membrane process to treat and reuse the cheese brine include:

Improving cheese shelf-life by reducing the amount of yeast and mold cells in the brine solution
Minimizing waste effluent requiring treatment
Reducing costs and maintenance of systems by reusing the brine solution

TurboClean® Brine elements feature a microfiltration membrane that, when combined with the patented TurboClean hard-shell and 47 mil parallel feed spacers, offers excellent performance in clarification of cheese and other food brines. For more information or questions, please contact MICRODYN-NADIR.

TurboClean microfiltration elements are USDA-accepted sanitary products that comply with 3-A Sanitary Standard 45-03 and are widely used in dairy and other process applications.

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Protein Concentration

Ultrafiltration is applied to either skim milk or whey to concentrate the dry matter to the required total solids (TS%). The commercially available powders’ names are based on the protein type: milk protein (named casein) or whey protein. Their protein content (percentage of protein in the dry matter) ranges from 34-80% (e.g. Whey Protein Concentrate “WPC60” has 60% protein in the dry matter or Milk Protein Concentrate “MPC60” has 60% protein in the dry matter).

High-protein products such as Whey Protein Isolate “WPI90” (90% protein in the dry matter) may first undergo a microfiltration (MF) treatment step to lower the fat content. Ultrafiltration (UF) is then applied to the MF defatted whey protein permeate to standardize and increase the protein content in the total solids.

To maximize the solids content, it is common to use diafiltration (dilution with water) in later stages to wash more small non-protein components (i.e. lactose and ash) into the UF permeate. It is also common to increase the feed spacer size of the element to maximize the solids content during the later stages of the UF system. Additionally, a tighter UF membrane is commonly used for the concentration of products with 80% protein (or more) in the dry matter.

NADIR® UP010 is a 10,000 Daltons (Da) molecular weight cut-off polyethersulfone (PES) UF membrane developed for use in food & dairy applications. This membrane is commonly used for whey protein and milk protein concentration applications. Combined with our sanitary TurboClean® outer shell, these membranes are ideal for milk and whey protein concentration.

NADIR® UP005 has a nominal molecular weight cut-off of 5,000 Da. It is a PES membrane that is suited for process separations, particularly applications involving protein concentration to high solids levels (80% or more protein in the dry matter). In these applications, a tighter UF membrane like UP005 is often used to minimize protein losses, leading to maximized product yield. Combined with the TurboClean shell, MICRODYN-NADIR offers the best performing UF element for dairy processes. Please read this case study to learn more about TurboClean® UP005 elements.

TURBOCLEAN® EXTREME (XT) ELEMENTS FOR PROTEIN CONCENTRATION

In places where chlorine use is restricted or undesirable due to concerns with chlorinated byproducts in wastewater streams, systems are cleaned using extreme conditions including alkaline cleaning solutions at high pH and high temperature. The elements in these systems must be able to withstand a cleaning pH range of 1-13 and cleaning temperatures up to 70°C (158°F) and must be heat-sanitizable at up to 85°C (185°F).

MICRODYN-NADIR offers TurboClean® Extreme Food & Dairy UP010XT and UP005XT elements primarily of polypropylene materials capable of tolerating these harsh conditions.

TurboClean® Extreme Food & Dairy UP010XT elements have a 10,000 Daltons (Da) molecular weight cut-off polyethersulfone (PES) UF membrane cast on a polypropylene support layer specifically developed for use in food & dairy applications where chlorine use is undesirable. This membrane is commonly used for whey protein and milk protein concentration applications. Combined with our sanitary TurboClean outer shell, these membranes are ideal for milk and whey protein concentration.

TurboClean® Extreme Food & Dairy UP005XT elements have a 5,000 Da molecular weight cut-off PES UF membrane cast on a polypropylene support layer. This membrane is suited for process separations, particularly applications involving protein concentration to high solids levels (80% or more protein in the dry matter). In these applications, a tighter UF membrane like UP005XT is often used to maximize product yield. Combined with the TurboClean shell, MICRODYN-NADIR offers the best performing UF element for dairy processes where chlorine use is restricted.

All of the membrane products listed above are available using feed spacers of various thicknesses to account for the total solids. For more information or questions, please contact MICRODYN-NADIR.

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Concentration & Demineralization

Whey has a fairly high salt content, about 8-12% of the dry matter. Demineralization (also known as desalination or de-ashing) enhances the nutritional value of whey products by removing salts and reducing the content of organic ions, such as lactates and citrates. In early dairy systems, whey was concentrated by evaporation and subsequently demineralized by electrodialysis and/or ion-exchange. While these methods are still used for highly mineralized whey products, nanofiltration (NF) is an advanced alternative for partial demineralization of whey.

NF membranes have a high permeability for monovalent salts (e.g. sodium, potassium and chloride) and a very low permeability for organic compounds (e.g. lactose, proteins and urea). The complex divalent (e.g. calcium) and multivalent ions (e.g. phosphate) are retained by the NF membrane. The use of NF to partially (25-30%) demineralize the whey products instead of evaporation followed by electrodialysis and/or ion-exchange has the advantage of simultaneous concentration and demineralization of whey, reducing processing costs. Diafiltration may also be used to achieve whey demineralization up to 45%. NF may also be used as a preliminary step to more complete (90-95%) demineralization of whey by electrodialysis and ion-exchange.

TurboClean® Food & Dairy NF elements using TRISEP® TS40 NF membrane are commonly used in dairy processing to concentrate and demineralize whey products. Combined with our sanitary TurboClean outer shell, these membranes are ideal for whey protein concentration and demineralization. These TurboClean NF elements are available using feed spacers of various thicknesses to account for the total solids present.

To meet specific customer requirements, MICRODYN-NADIR offers various other NF membranes with a wide range of feed spacers including 31 mil diamond, 46 mil diamond, 47 mil parallel and 65 mil diamond. For more information or questions, please contact MICRODYN-NADIR.

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Dairy Product Concentration

PRODUCT CONCENTRATION FOR EVAPORATORS

Reverse osmosis is often used as a supplement to evaporation as it is a very efficient way of removing water from milk or whey (reducing volume) prior to the evaporation stage. By installing a reverse osmosis system upstream of an existing evaporator, the capacity of the evaporator may be reduced considerably, resulting in significant savings in capital and operating costs.

INCREASING SOLID-NOT-FAT (SNF) LEVELS OF MILK

Reverse osmosis is commonly used to concentrate skim milk, whole milk or whey protein to increase solid-not-fat (SNF) levels. Because reverse osmosis primarily removes water, it may be applied as an energy-efficient alternative to other common ways of increasing the SNF levels in milk including evaporation or the addition of milk powder.

WASTEWATER PRODUCT RECOVERY & REUSE

Product recovery using reverse osmosis has increasingly become an option as dairy production facilities attempt to reduce waste and increase the production output. Reverse osmosis systems can treat wastewater streams to minimize disposal costs and to recover water for reuse. In some cases, the concentrate from the waste stream is a valuable consumer product.

TurboClean® Food & Dairy RO elements may be used to concentrate products. TRISEP® ACM2 membrane is commonly used to remove water and reduce volume but will not alter the relative composition of the whey or milk components prior to evaporation. Combined with our sanitary TurboClean outer shell, this membrane is ideal for the concentration of product. This product is available using feed spacers of various thicknesses to account for the total solids content.

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Evaporator Condensate Polishing

Permeate streams from reverse osmosis or nanofiltration processes as well as condensates from evaporators are essentially water. With additional cycles of reverse osmosis, this water can be purified or “polished” to a level where it may be reused again for cleaning purposes. With further heat or UV treatment, this water may even be used as process water.

Some sugar, food, dairy and pharmaceutical production facilities have excess amounts of water which must be discharged. Discharged water is typically associated with emission taxes depending on organic levels as well as other factors. Reverse osmosis may be used to lower the content of micro-organisms, TOC and COD of the discharge water and significantly reduce emission taxes.

TurboClean® High Purity RO elements may be used to polish permeate streams or condensates from evaporators. For more information or questions, please contact MICRODYN-NADIR. This product is available using feed spacers of various thicknesses to account for the total solids content.