APPLICATION OF MEMBRANE TECHNOLOGY IN THE DAIRY INDUSTRIES
Applications
The diversity of existing membrane technology allows a wide range of applications in the dairy industry, such as:
- Development and management of whey;
- Concentration of milk to improve its technical characteristics in the manufacture of derivatives;
- Separation of fat from whole milk;
- Separation of lactose in whole milk;
- Concentration of brine for the salting of the cheese;
- Elimination of antibiotics;
- The concentration and separation of immunoglobulin antibodies;
- Separation of caseinic acids;
- Wastewater treatment.
Description of the applied technology
The technologies used individually or in combination are:
Microfiltration and Ultrafiltration
- It is the same technique, but with different pore membranes, and consists of passing a fluid inside a tubular membrane of organic or inorganic type and, due to the back pressure, make it pass through the membrane.
- The flow depends on the type of pores, the type of membrane and the characteristics of the circulating fluid. A Porosity is 0.2 to 2 microns in MF and 450 – 350,000 Dalton UF, pressures of 2-4 bar are required;
- Microfiltration also allows the removal of fat in the whey / WPC and the separation of casein;
- Ultrafiltration allows concentration of skim milk protein, concentration of whey protein, and concentration of isolated whey proteins.
Nanofiltration
- It is also a physical separation through a membrane and is based on molecular size and electric charge, which in theory allows the separation of monovalent ions from polyvalent ones, with pore size of 200-1000 Dalton;
- Demineralization of serum and lactose.
Inverse osmosis
It is a process of separation, which separates the water from the rest of the components present, acting at the same time as a concentrator. The pore size is less than 150 Dalton. The working pressure can be from 15 to 30 bars;
- Concentration of skimmed milk;
- Serum concentration;
- Concentration of serum permeated by UF;
- Regeneration of the evaporator permeate / condensate.
Electrodialysis
It is an electrochemical separation process in which, under the influence of an electric field, the ions, when in solution, move through the selective membranes, directly proportional to the specific conductivity and inversely proportional to the number of molecules dissolved. The working potential is 1 -20 and the pressure is 1-1.5 bar.
The use of these by-products, which would often go to the sewers, produces the following benefits:
- Revaluation of the plant, through the amortization with the sale of these by-products;
- Reduces the construction costs of the treatment plant;
- Reduces operating costs;
- These are portable compact stations;
- It takes up little space;
- Moderate energy consumption compared to other separation systems (centrifuges, evaporators, stills, etc.);
- In some cases, especially after a reverse osmosis process, the water produced can be reused;
- They are adaptable to all sizes of the industry;
- Minimal waste production.
TECHNIQUES USED FOR EACH APPLICATION
> Use and treatment of serum dairy products
Characteristics
- Contains 20% protein, 75% lactose, 5% mineral fraction of dry matter.
- They are used in confectionery, beverages, bakery, meat industry, food industry in general;
- It has gelling, water retention, emulsifying and foaming properties;
- It can dry out, evaporate or crystallize.
Treatment techniques
- Ultrafiltration is better used with ceramic systems than with organic ones;
- The cut-off point is between 25 and 50 k Dalton;
- Microfiltration (1mm cutoff) can also be used to separate fats, proteins, denatured and microbial residues, and ultrafiltration only to separate proteins.
> Concentration of milk to improve your technique in the manufacture of derivatives
Treatment techniques
MICROFILTRATION
- Microfiltration of skimmed milk produces an adequate casein / protein ratio in the cellar, using 0.05-0.2 micron membranes.
- The permeate has a market value, based on its serum protein load;
- Normally retained origin of good concentration and low calcium content, useful in the case of mozzarella, working at a low pH;
- Concentrates skim milk in the production of Dambo, Camembert and Emmental cheese.
ULTRAFILTRATION
- It is used in the manufacture of cheese, where the raw material usually suffers less loss of protein and less loss of whey fat, and in some cases, such as buffalo milk, it improves the content of calcium and magnesium ;
- If the retention of milk is used, a cottage cheese is produced, which has better sensory characteristics than the usual processes; With pasta filato type cheeses, a high protein and fat concentrate can be obtained;
- The production of yogurt using UF, with a pore size of 30 K Dalton, results in a product with a firm clot.
Treatment techniques
MICROFILTRATION
- Microfiltration of skimmed milk produces an adequate casein / protein ratio in the cellar, using 0.05-0.2 micron membranes.
- The permeate has a market value, based on its serum protein load;
- Normally retained origin of good concentration and low calcium content, useful in the case of mozzarella, working at a low pH;
- Concentrates skim milk in the production of Dambo, Camembert and Emmental cheese.
TECHNIQUES USED FOR EACH APPLICATION
> Separation of fat from milk
ULTRAFILTRATION
- With cuts in the 0.5k Dalton range, short chain fatty acids are removed, which are generally responsible for the strong odors characteristic of milk, such as goat milk.
MICROFILTRATION
- Ceramic membranes with a pore size of 2 microns and temperatures of about 50 ° C are used.
> Lactose separation
MICROFILTRATION
- It is separated by removing the proteins from the acidified sera;
- The amount of lactose in milk is reduced to only 3.8% of the original, and concentrates the solids by 8%.
Other apps
- Production of powdered cheese and pre-cheese bases: Combining ultrafiltration and evaporation in a scraped film equipment, it is possible to obtain powdered cheese and pre-cheese bases (in triple recirculation) with 64% dry matter, from of which can be produced later different products through bacterial fermentation;
- The separation of acid caseinates: The process involves the hydrolytic acidification of the milk until it reaches pH values close to 4.9 and its recirculation in an electrodialysis system that separates the acid caseinates at temperatures below 10 ° C to avoid microbiological problems. It may also involve the aggregation of fractions generated by hydrolysis by the addition of phosphate of calcium and the subsequent use of ultrafiltration techniques.
- Elimination of antibiotics in milk: Contaminants such as sulfamethazine can be eliminated from milk by a combined process of microfiltration and diafiltration, with recirculation, using hollow fiber polysulfone membranes, with a cut-off of 10,000 Dalton and temperatures of 50 ° C. Similar conditions are useful for the separation of β-lactams, using the same type of membranes but with 20,000 Dalton cuts and temperatures of 54 ° C;
- Immunoglobulin concentration and antibody separation: This is usually done using microfiltration and ultrafiltration techniques. It involves the use of transmembrane pressures of 2 to 4.5 psi and appropriate pH adjustments to ensure selectivity.
Conclusions
- The economic and technological benefits of many of the processes are undeniable;
- These techniques are closely related to improving profitability and reducing execution and operating costs;
- Adaptable to particular needs;
- 24 / 24h service guarantee.