Cold-pressed grape seed oil contains many bioactive compounds and its production enables the valorization of grape seeds as a by-product of winemaking. However, the incorporation of oils into food is ...associated with losses of active compounds and incompatibilities with the complex food matrix. Encapsulation is considered a process that could overcome these obstacles and enable a more diverse use of plant oils in the food sector. In this study, we developed an improved encapsulation process, submerged-nozzle dispersion (SND). SND aims at the encapsulation of active ingredients using highly viscous carrier materials. We used SND for the encapsulation of cold-pressed grape seed oil in alginate. The alginate stabilized the emulsions and provided stable conditions for the formation of encapsulates. The dried encapsulates were in the form of elongated particles with an average width below 150 μm; the oil content in encapsulates reached above 80% and encapsulation efficiency was up to 90%, depending on the formulation. Encapsulates exhibited satisfactory mechanical properties, suggesting they could mix well with other food ingredients. The SND encapsulation process developed in this study could be successfully applied to the encapsulation and protection of cold-pressed plant oils to be used as a source of valuable nutrients in foods.
•Agar was impregnated with Zn-minerals to produce nanocomposite films.•Nanocomposites exhibited different morphologies, properties and functionality.•Reinforcing with minerals improved mechanical, ...optical and thermal properties.•Nanocomposite films release Zn(II) inducing antimicrobial effect.
New mineralized, agar-based nanocomposite films (Zn-carbonate and Zn-phosphate/agar) were produced by a combination of in situ precipitation and a casting method. The presence of minerals significantly influenced the morphology, properties and functionality of the obtained nanocomposites. Reinforcement with the Zn-mineral phase improved the mechanical properties of the carbonate-mineralized films, but had a negligible effect on the phosphate-mineralized samples. Both nanocomposites showed improved optical and thermal properties, better Zn(II) release potential in a slightly acidic environment and exhibited antimicrobial activity against S. aureus. These results suggest that Zn-mineralized agar nanocomposite films could be potentially used as affordable, eco-friendly and active food packaging materials.
•Zn-mineralized alginate nanocomposites were produced in one-step method.•Presence of Zn-mineral phase has increased total nanocomposite Zn(II) content.•Stability and Zn(II) release are modulated by ...the presence of mineral phase.•Nanocomposites release Zn(II) inducing strong antimicrobial effect.
New bioactive and antimicrobial biomaterials were produced by alginate-mediated biomineralization with Zn-mineral phase. The synthesis procedure is simple, cost-effective and resulted in two different Zn-mineralized alginate nanocomposites, Zn-carbonate/Zn-alginate and Zn-phosphate/Zn-alginate. The presence of Zn-mineral phase and its type, have significantly affected nanocomposite morphology, stability, total metallic loading and potential to release Zn(II) in physiological environment. Antimicrobial experiments showed that both types of Zn-mineralized nanocomposites exhibit strong antimicrobial effect against Escherichia coli, Staphylococcus aureus and Candida albicans. These results suggest that alginate biomineralization, where minerals are salts of essential metallic ions like Zn(II), represents a good strategy for designing multifunctional biomaterials for potential biomedical applications.
Capsulation of non-dewaxed propolis in gum Arabic via freeze-drying maintains higher bioflavonoid content in comparison to spray-drying. Encapsulated propolis also prolongs fish oil shelf life.
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•Gum Arabic encapsulates non-dewaxed propolis better than inulin or maltodextrin.•Freeze-drying is more efficient in encapsulating propolis than spray-drying.•Encapsulated propolis powders prolong shelf life of oil rich in omega-3 fatty acids.•Omission of dewaxing is reflected in higher phenol levels and better stability.•Different analysis confirm successful encapsulation of propolis with gum Arabic.
The aim was to obtain alcohol-free, water-dispersible propolis powder from non-dewaxed propolis extract, with high levels of phenols, with either freeze-drying or spray-drying. Optimisation was performed with different wall materials, centrifugation settings and propolis:carrier ratios, and was carried out by monitoring the effect of one parameter at a time on the dependable variables. The powders obtained contained high phenol levels, which included known bioactive components, and also showed high dispersibility in cold water and high antioxidant activity. Furthermore, the propolis powders were stable in water for up to 24h, and the release of encapsulated phenols did not change across different environmental values, as pH 3–6. Differential scanning calorimetry showed that propolis interacts with and stabilises the carrier material (gum Arabic), also high pressure liquid chromatography showed that the profiles of the powders remained unchanged across all encapsulation techniques. This study demonstrates that the same propolis formulations can be fine-tuned to suit specific final applications and confirms that freeze-drying is a viable alternative to the more established spray-drying for encapsulation of propolis. This study also demonstrates that non-dewaxed propolis extract is a better alternative for encapsulation purposes, as no phenolic compounds are lost during its processing.
•Bimetallic mineral phase was incorporated in alginate to produce nanocomposites.•Presence of mineral phase within alginate was confirmed by FTIR and Raman analysis.•Nanocomposite morphology was ...influenced by the type of mineral precursor.•Nanocomposites exhibited strong antimicrobial effect.
Two bimetallic (Zn/Cu) alginate based nanocomposites, impregnated with carbonate or phosphate mineral phase, were prepared by a facile procedure. Mineralized samples exhibited different morphologies and properties when compared to the non-mineralized sample. Antimicrobial testing against Escherichia coli, Staphylococcus aureus and Candida albicans showed that mineralized samples are more efficient than non-mineralized in elimination of microorganisms. The results of this study suggest that bimetallic mineralized alginates could be potentially used as affordable, easy to produce antimicrobial materials.
U ovoj disertaciji je ispitivana inkapsulacija prehrambenih aroma uz primenu različitih metoda inkapsulacije i u kombinaciji sa prirodnim i sintetičkim nosačima. Cilj istraživanja je bio dobijanje ...inkapsulata kako tečnih tako i čvrstih aroma koje se najčešće koriste u prehrambenoj industriji. Ispitivana su tri nosača za inkapsulaciju aroma: karnauba vosak, alginat i polivinil alkohol. Kao model arome su korišćene: etil vanilin, komercijalno dostupna aroma kokosa i D-limonen.Karnauba vosak je korišćen kao nosač za inkapsulaciju etil vanilina, pri čemu su dobijene sferne čestice čiji je prečnik uglavnom bio ispod 250μm. Čestice na bazi karnauba voska sa etil vanilinom su dobijene primenom disperzione (emulzifikacione) metode i disperzione tehnike (disperzija komprimovanim vazduhom). Metodom disperzije vazduhom su dobijene čestice pravilnijeg sfernog oblika sa većom inkapsulacionom efikasnošću. Takođe, termička svojstva inkapsulisanog etil vanilina su poboljšana u poređenju sa slobodnom aromom. Termičko otpuštanje inkapsulisanog etil vanilina se odigravalo na višim temperaturama (do~270°C) u poređenju sa slobonom aromom (do ~220°C).Ca-alginatne čestice sa tečnim i čvrstim aromama su dobijane metodom elektrostatičke ekstruzije. Inkapsulacijom etil vanilina u Ca-alginatni matriks su ostvarena bolja termička svojstva inkapsulisane arome uz postizanje kontrolisanog termičkog otpuštanja arome u širem temperaturnom opsegu u odnosu na slobodnu aromu. Aroma kokosa i D-limonen su inkapsulisani u Ca-alginatne čestice primenom iste procedure kao i u slučaju inkapsulacije etil vanilina. Alginat je pokazao dobra emulgujuća svojstva, što je osnovni uslov za postizanje visoke inkapsulacione efikasnosti. Rezultati termičke analize su pokazali da obe arome u inkapsulisanom obliku imaju bolja termička svojstva u odnosu na slobodne arome. Rehidracija je korišćena za ispitivanje adsorpcije vode u inkapsulate uz razvoj novog modela rehidracije.Polivinil alkohol je u kombinaciji sa alginatom korišćen za dobijanje čestica sa inkapsulisanim etil vanilinom metodom elektrostatičke ekstruzije. Primenom viših napona kod metode elektrostatičke ekstruzije-elektrospininga dobijeni su filmovi na bazi polivinil alkohola koji se sastoje od nanovlakana. Filmovi na bazi polivinil alkohola su pokazali dobra hemijska, mehanička, termička i antimikrobna svojstva.
Partially purified polysaccharides (FP) and hot alkali extract (FNa) obtained from fruiting bodies of the wild basidiomycete Grifola frondosa were examined for their antimicrobial, antioxidant and ...cytotoxic activity. The structural properties of FP and FNa samples were investigated by FT-IR and high resolution 1H- and 13C-NMR spectroscopy. From a group of various G - and G + bacteria the antibacterial effects were highest against the G + B. cereus. FNa was the better antioxidant shown by the lower EC sub(50) values of DPPH scavenging ability, ferric-reducing antioxidant power and ferrous ion-chelating ability. Ferric-reducing antioxidant power and ferrous ion-chelating ability were mostly linked to total polysaccharides, total- and beta -glucan content, as well as total protein content. Both extracts displayed a moderate dose dependent antiproliferative action towards malignant human breast cancer MDA-MB-453, cervical adenocarcinoma HeLa and myelogenous leukemia K562 cells not observed in the non cancer derived MRC-5 fibroblasts. The highest effect was found in HeLa cells for FP extract. The mean diameter of Ca-alginate bead loading FP was 960.7 mu m while the mean diameter of beads encapsulating FNa extract was 1051.7 mu m.
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