Milk serum, which represents up to 90% of the gross product in cheesemaking, has been considered for years only as a supplement for animal feeding or, where it could not be used for this purpose due to shipping problems, as a waste byproduct to deal with. Sweet milk serum is a liquid diluted byproduct derived by cheese production. It contains lactose, proteins and minerals, however, the serum can be processed in order to extract minerals, e.g. through electrodialysis. This is how we can make demineralized milk serum. If compared to other products, it has better organoleptic characteristics, low acidity and low solubility.
Characteristics of main milk serum derivatives
Largely employed as base ingredient in the infant nutrition, as a substitute for breast milk, demineralized milk serum is used as raw material for multiple food products: it is used to produce dairy products (whole milk production, ice cream production, spreadable cream cheese, cottage cheese and other kinds of cheese); in the baking industry (cakes, sweets); in the meat industry (deli meats, salami and pate).
The serum contains, besides proteins, lactose and mineral salts that can be recovered and turned into high added-value substances.
Demineralization process aims to maintain lactose and proteins of the serum while decreasing the mineral content (up to -90%). It is a process based on ion–exchange resins, i.e. insoluble organic substances that are able to exchange their ions with other ions having the same charge and contained within the solution in which they are submerged.
Demineralized serum, which is subsequently crystallized and dried up, is largely used as base ingredient in nutrition for infancy, as a substitute for breast milk; moreover, as we have already mentioned, it is also employed as raw material for several food products and in the pharmaceutical industry.
Demineralization process takes place, as already mentioned, through electrodialysis or ion – exchange resins, but those are not the only technologies used, in fact nano-filtration and ultrafiltration are other possible technologies employed. Membrane technologies, at the present, allows to significantly value serum and in particular we must cite the following applications:
ultrafiltration, which allows to almost totally recover proteins and fats in concentrated form, with the possibility to further process – for recovering lactose – the permeate that contains lactose and mineral salts, besides obtaining lactose powder; inverted osmosis, which concentrates the whole mass about three times, and this mass can be concentrated even further by heat treatment to obtain a protein flour. The permeate is good quality water which can be reused into cheese factory or discharged in surface water; nano-filtration, which is similar to inverted osmosis but, unlike the first one, allows the passage of a portion of mineral salts contained in the permeate (especially chlorides), then providing a partially demineralized concentrate.
High protein content and low fat content of milk serum in its demineralized powdered form is well known; these qualities, within a global market that is growing more and more technologic and which focuses on products more suitable for a health-conscious lifestyle, represent an added value for the growth of this ingredient. The increasing world population and the growing demand for artificial milk are a contributing factor to this phenomenon.
The market for demineralized powdered milk serum is segmented based on how the ingredient is used (artificial milk, baking products, sweet baking products, milk and dairy products, beverages and others). Among all the segments, artificial milk should be the most dominant on long-term and also from a financial perspective. This ingredient is also widely used in the beverage industry, especially to support foaming, stability and mouth feel. Another leading industry for the growth of this ingredient is packaged infancy food products.
However, there is also a geographical segmentation, North America and Western Europe are mature markets, while emerging markets, such as Pacific Asia, will have substantial growth opportunities over the next ten years. These favorable predictions are based in the first place on the technological advance of processing industries for milk serum and on an increasing consumption of packaged food products and low-calorie products both in the Pacific Asia and in Middle East and Africa.