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This study aimed to evaluate the physical–chemical properties (particle size, zeta potential, encapsulation, and thermal stability), antioxidant properties, antibacterial properties and casein-flavonoid interaction studies of soluble complexes, called caseinates of red propolis. The caseinates of red propolis were successfully prepared using the spray-dryer technique, which presented two populations of nanometre and micrometre particles, and were able to encapsulate flavonoids and isoflavonoids from the red propolis extract as a soluble complex. SEM analysis demonstrated casein nanoparticles and fat globules combined with lipophilic compounds (terpenes) from red propolis extract. FTIR analysis proved the encapsulation of flavonoids into caseinates. The thermogravimetric assays demonstrated thermal stability of red propolis caseinates and DTA analysis observed the denaturation during the coagulation temperature. The fluorescence, antioxidant, Folin–Ciocalteu method and chromatographic assays have shown that flavonoids bind to the amino acid residues present in the casein protein matrix, demonstrating a reversible interaction between flavonoids and casein amino acids. Dissolution studies prove the formation of a casein-flavonoids soluble complex and can bring benefits and increase the process of absorption of flavonoids by biological membranes. Despite the interaction of flavonoids with casein amino acids, caseinates of red propolis demonstrated antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. The caseinates of red propolis can be easily incorporated in foods such as cakes, pies, dairy and cocoa such as foods bio-preservatives. The caseinates of red propolis can be manufactured by the pharmaceutical and nutraceuticals industries as intermediary bioproduct in the powder form for supplements, capsules and oral emulsion systems for beverages as yogurts. [ABSTRACT FROM AUTHOR]

Objectives: The goal of this study was to develop novel compositions of edible protein coatings based on immunoglobulin (Ig) fraction from bovine milk. Protein coatings can be used to protect foods against microbial, chemical, and physical damage. We developed novel compositions of edible protein coatings based on immunoglobulin (Ig) fraction from bovine milk. A lot of Ig could be obtained from under-utilized side streams of dairy industry. To the best of our knowledge, such use of the Ig fraction has not been published earlier. Materials and Methods: Bovine colostral Ig's were incorporated in edible films based on various milk proteins and investigated the characteristics of the films including solubility of Ig's and nisin and on technological properties of films. Ig's specific to cariogenic bacteria Streptococcus mutans and Streptococcus sobrinus were produced to colostrums by hyperimmunizing cows before parturition. Results: The milk Ig rich fraction suited well as a component of milk protein films. The Ig's dissolved from the films very rapidly. Nisin, commoly used for food protection, was used as a model of antimicrobial peptide. Nisin was released biologically active from both β-lactoglobulin (β-lg) and β-lg/Ig films. Nisin exerted its bactericidal effect at clearly lower concentrations in the β-lg/Ig films when compared with β-lg film. Nisin also retained its activity better in film containing Ig-enriched whey. Incorporating Ig-enriched whey into films enhanced adhesion and tensile strength of the films. The Ig-enriched whey also affected strongly on the appearance of films based on commercial whey protein concentrate in a dose-dependent way by making the films more smooth, transparent, and clear which are all favoured properties in most food and pharmaceutical applications. Conclusions: Biologically active Ig's can be successfully incorporated in and released from milk protein based edible films. The content of Igs in films affected considerably technological properties of these films. Composition of other proteins in films had effect on preservability and release of Igs. [ABSTRACT FROM AUTHOR]

Finding new green ways of producing proteins has never been of such critical public interest, both to meet consumers' needs and to preserve the environment. Milk proteins are among the most attractive protein types due to their high nutritional value and attractive functional properties. In this work, the separation of caseins by conventional chemical acidification was compared with electrodialysis with bipolar membrane coupled to an ultrafiltration module (EDBM-UF), a green process that allows the precipitation of caseins by H+ generated in situ by the bipolar membrane and, simultaneously, the production of a separated NaOH stream from OH− electrogenerated by the bipolar membrane. Caseinate production using this NaOH stream by-product and the quantity of NaOH needed to produce caseinates from both methods were also investigated. Hence, the purity and composition of caseins and caseinates were compared in terms of protein, ash, and lactose contents as well as mineral composition. The results showed for the first time that caseinates can be produced by solubilizing caseins with NaOH stream from the EDBM process. Furthermore, the caseins and caseinates produced by EDBM-UF were equivalent in terms of lactose and protein contents to their respective caseins and caseinates that were chemically produced but presented slightly lower sodium content and 3 to 4 times higher magnesium and calcium contents. The fact that calcium and magnesium are likely bound to milk caseins would ensure their favorable absorbability. These caseins or caseinates from the new EDBM-UF process could be suitable as an improved protein-based calcium or magnesium supplement, both for their enhanced nutritional quality and because they are produced by a "green" process. [ABSTRACT FROM AUTHOR]