Membrane technologies are rapidly gaining popularity because they are not just more efficient than conventional methods but also less expensive. They are often considered “green technologies” for the same reason. Membrane filtration also prolongs the shelf life of food products, eliminating the need for preservatives and additives.
There are several types of membrane solutions for dairy processing. The major ones are as follows:
Microfiltration (MF)
MF can remove particles heavier than 0.1 microns. These particles include micelles, bacteria, spores, macro-organisms, and different suspended solids. In dairy processing, this method of filtration removes soluble proteins, casein micelles, and bacteria.
Ultrafiltration (UF)
UF is often carried out after MF. It is a standard form of filtration for milk and milk products because it can retain proteins, and lipids and helps in the standardization of milk by enriching the protein content.
In whey processing UF process is deployed to make different grades of whey protein concentrates.
Nanofiltration
Nanofiltration is the third step of membrane processing in the dairy industry. It is applied just before RO to separate several small molecules. These may include divalent salts and sugars. Nanofiltration is one of the most efficient methods of producing lactose-free milk.
Partial demineralization and concentration of whey are also carried out through nanofiltration. Nanofiltration membrane processes are also deployed for partial de-ashing of skimmed milk in order to meet the ash limit for skimmed milk powder (SMP). Along with, de-ashing, nanofiltration also removes water reducing the load & cost in the evaporation step.
Reverse Osmosis
Reverse Osmosis is usually used for the concentration of skimmed or whole milk. It operates on very high pressure and can separate monovalent salts along with small solutes. It allows only water to pass through while retaining all dissolved milk solutes. Dewatering of milk helps in SNF enhancement and saves logistics costs, as it reduces the volume of water in the milk during transportation. RO membranes are also deployed for condensate polishing to remove the organics & organic solute, providing good quality water for recycling.
Membrane processing in the dairy industry, thus, includes the use of 4 membranes in the following order:
Microfiltration > Ultrafiltration > Nanofiltration > Reverse osmosis
Their specific applications are as follows:
- Whey Protein clarification and concentration: Ultrafiltration
- Processing of milk for cheese production: Ultrafiltration
- Lactose concentration: Nanofiltration
- Standardization of milk (protein): Ultrafiltration
- Milk concentration & deashing: Nanofiltration / Reverse osmosis
- Bacteria removal: Microfiltration
- De-ashing: Nanofiltration/ Ultrafiltration
- Condensate Polishing: Reverse osmosis, Forward osmosis
- SNF enhancement: Nanofiltration
Conclusion
Membrane filtration is a future-first technology that makes dairy processing faster, more efficient, and affordable. It also reduces waste and minimizes the need for preservatives.
Permionics uses an advanced Nanofiltration system to remove almost 50% of water content from skimmed milk and enrich SNF to meet the necessary standards. Its proprietary NF membrane is also capable of eliminating partial ash without affecting the byproduct.
Please visit our website for more details and information on our latest membranes
