Whey is the main by-product of cheese and casein manufalcture, which represents one of the main pollutants of the food industry from an environmental point of view, due to uneconomic management. However, whey is a rich source of proteins such as lactoferrin (Lf), lactoperoxidase (LPO) and beta-lactoglobulin (BLG), with many structural and functional properties, that represents great potential for use in the food and pharmaceutical industry. In a doctoral thesis we demonstrated that the temperature stability of Lf depends on the degree of saturation with Fe3+ ions, while the latter does not affect the pH stability of Lf. By carrying out enzymatic hydrolysis of Lf using different enzymes and enzymatic reaction conditions, we obtained diverse Lf hydrolysates with antibacterial and antioxidant activity. We demonstrated for the first time the antibacterial activity of Lf and Lf peptides against Latilactobacillus sakei. The structural and enzymatic activity of LPO depended on pH, temperature, type and molar concentration of the buffer, while the presence of 10 mM Ca2+, Mg2+ and Na+ only affected the structural stability of LPO. Partial removal of Fe3+ and Ca2+ from LPO resulted in lower temperature stability and lower enzymatic activity of LPO. BLG as part of WPI was used to form gels by the heat and cold gelation method, which successfully encapsulated vitamin D3 and Lf peptides. WPI gels formed under different conditions had different stability in simulated gastric fluid due to structural differences. In addition, we demonstrated that BLG A binds two vitamin D3 molecules at all different pH values that affect its quaternary structure. With the research covered in the doctoral thesis, we demonstrated many positive physico-chemical and functional properties of the analyzed proteins, that will have positive contribution to the efficient use of whey.
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