Fractionation and processing of whey proteins and exploitation of the residue for the formulation of new functional foods and food supplements

In 2017, milk production reached more than 750 million tones and is rising. The world's major producers are the USA and the EU, 70% of the total amount. In the production of cheese and curd, whey represents about 90% of processed milk, which speaks of the enormous proportion of whey remaining as secondary raw material. It is estimated that about half of the world's whey production ends in sewage treatment plants or watercourses, where it presents a serious ecological problem.

The currently available quantities of whey are large. At the same time, this is a long-term available resource with a trend of increasing quantities (2% annual growth), thus supporting emerging markets for secondary raw materials. 

Similarly, milk production and consumption are seasonally fluctuating, and excess milk is often processed into permanent UHT processed milk with a lower added market value. Also, the process destroys some physiologically active serum proteins. 

After removal of the casein part of proteins, the lactose, minerals (Ca, Mg, Na, K, P, Cl-), fats and a large group of whey proteins (β-lactoglobulin, α-lactalbumin, bovine serum albumin, immunoglobulins, glycomacropeptide, lactoferrin, lactoperoxidase, lysozyme, osteopontin, etc.) remain in whey. Recently, researchers put particular attention to whey proteins, which are often used, due to their exceptional nutritional properties, as functional additives of food products and dietary supplements. They are a rich and balanced source of amino acids, but they also have numerous physiological effects from antimicrobial, immunomodulatory to anticancer agents.

According to Slovenian statistical office data, a large part of Slovenian whey is used for feeding livestock, disposed of for treatment into wastewater treatment plants and to a lesser extent sold directly to consumers. Exported is mainly whey in condensed form to customers who process it into high added value products.

Isolated whey proteins exhibit better functional and biological properties than when mixed whey powder. The extraction of individual whey proteins from milk is carried out using a different membrane and chromatographic methods. While at the laboratory level the purity and biological activity of proteins reach the desired quality, this is often not the case in industrial processes. The purity of proteins thus largely corresponds to the so-called "food-grade" quality. For the production of raw materials for the starting milk mixtures and pharmaceuticals, more efficient procedures are needed at the industrial level. There are also several uncertainties in the production of hydrolysates of individual whey proteins, which express additional or different physiological effects from native proteins (reduced allergenicity, prebiotic role, increased antimicrobial activity).

There are several reasons for the increase in demand in this area.
We are confronted with the rise of chronic infectious diseases and, on the other hand, resistance to antibiotics and the lack of natural antimicrobial agents. Thus, lately, much attention is paid to whey proteins, which express numerous physiological effects from antimicrobial, immunomodulatory to anti-carcinogenic.

We are facing the ageing of the population and increasing health problems associated with ageing. Ageing is a dynamic process that manifests itself with numerous changes in the body composition and changes in the physiological, psychological and cognitive state. Despite the lower energy requirements for food in this age, it is necessary to provide all the essential macro and micronutrients in an optimal balance. Seniors often experience sarcopenia, an age-dependent decrease in muscle mass, which is often due to under-protein-rich foods. Whey proteins are here a rich and balanced source of amino acids.

In addition to demand in the market for dietary supplements and natural medicines, there is a growing demand for individual whey proteins, primarily for the preparation of infant formulas.

In the final processes of obtaining individual whey proteins, the proteins contained in the liquid must be dried or stabilised. The established methods are spray drying and lyophilisation. The proteins thus obtained are highly hygroscopic and in contact with water, enzymes, light, high temperature, etc. subject to disintegration. According to the chosen end-use method, it is, therefore, necessary to introduce new solutions that improve the persistence or the preservation of functional properties of proteins during the transport to the target sites and controlled release.