Steva Lević

Microencapsulation of Flavors in Carnauba Wax

The subject of this study is the development of flavor wax formulations aimed for food and feed products. The melt dispersion technique was applied for the encapsulation of ethyl vanillin in wax microcapsules. The surface morphology of microparticles was investigated using scanning electron microscope (SEM), while the loading content was determined by HPLC measurements. This study shows that the decomposition process under heating proceeds in several steps: vanilla evaporation occurs at around 200 °C, while matrix degradation starts at 250 °C and progresses with maxima at around 360, 440 and 520 °C. The results indicate that carnauba wax is an attractive material for use as a matrix for encapsulation of flavours in order to improve their functionality and stability in products.

Entrapment of ethyl vanillin in calcium alginate and calcium alginate/poly(vinyl alcohol) beads

Electrostatic extrusion was applied to the encapsulation of 3-ethoxy-4-hydroxybenzaldehyde (ethyl vanillin) in calcium alginate and calcium alginate/poly(vinyl alcohol) beads. The calcium alginate/poly(vinyl alcohol) hydrogel spheres were formed after contact with the cross-linker solution of calcium chloride, followed by the freeze-thaw method for poly(vinyl alcohol) gel formation. The entrapment of aroma in beads was investigated by FTIR and thermal analysis (thermogravimetry/differential thermal gravimetry; TGA/DTG). The mass loss in the temperature range of 150–300°C is related to degradation of the matrix and the release of ethyl vanillin. According to the DTG curve, the release of ethyl vanillin occurs at about 260°C. TGA measurements of the stored samples confirmed that formulations were stable for a period of one month. FTIR analysis provides no evidence for chemical interactions between flavour and alginate that would alter the nature of the functional groups in the flavour compound.

Carnauba wax microparticles produced by melt dispersion technique

Melt dispersion technique was investigated for carnauba wax microparticles production. Microbeads with spherical shape and narrow size distribution were produced. The main objective of this study was to investigate the effect of significant process variables (initial wax concentration, stirring speed, stirring time, and surfactants) on sphericity, size distribution, and morphological properties of wax microparticles. Optimal conditions were evaluated on the basis of particle size distribution and visual analysis. Surface morphology of microparticles was characterized by scanning electron microscopy (SEM). Effects of process conditions on the size distribution of particles were evaluated by sieve analysis. Main purpose of these investigations was to apply optimized parameters to aroma encapsulation for their use in food and feed industry.

Synthesis and antimicrobial properties of Zn-mineralized alginate nanocomposites

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.

Effects of different carrier materials on physicochemical properties of microencapsulated grape skin extract

AbstractThe goal of this study was to investigate the characteristics of grape skin extract (GSE) spray dried with different carriers: maltodextrin (MD), gum Arabic (GA) and skim milk powder (SMP). The grape skin extract was obtained from winery by-product of red grape variety Prokupac (Vitis vinifera L.). The morphology of the powders, their thermal, chemical and physical properties (water activity, bulk and tapped densities, solubility), as well as release studies in different pH conditions were analyzed. Total anthocyanin content and total phenolic content were determined by spectrophotometric methods. MD and GA-based microparticles were non-porous and spherical, while SMP-based ones were irregularly shaped. The process of spray drying Prokupac GSE using these three carriers produced powders with low water activity (0.24–0.28), good powder characteristics, high yields, and solubility higher than 90%. The obtained dissolution/release profiles indicated prolonged release of anthocyanins and phenolic compounds in different mediums, especially from GSE/GA microparticles. These results have shown that grape skin as the main by-product of wine production could be used as a source of natural colorants and bioactive compounds, and microencapsulation as a promising technique for the protection of these compounds, their stabilization in longer periods and prolonged release.

Mineralized agar-based nanocomposite films: Potential food packaging materials with antimicrobial properties

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.

Biointerface dynamics – Multi scale modeling considerations

Irreversible nature of matrix structural changes around the immobilized cell aggregates caused by cell expansion is considered within the Ca-alginate microbeads. It is related to various effects: (1) cell-bulk surface effects (cell-polymer mechanical interactions) and cell surface-polymer surface effects (cell-polymer electrostatic interactions) at the bio-interface, (2) polymer-bulk volume effects (polymer-polymer mechanical and electrostatic interactions) within the perturbed boundary layers around the cell aggregates, (3) cumulative surface and volume effects within the parts of the microbead, and (4) macroscopic effects within the microbead as a whole based on multi scale modeling approaches. All modeling levels are discussed at two time scales i.e. long time scale (cell growth time) and short time scale (cell rearrangement time). Matrix structural changes results in the resistance stress generation which have the feedback impact on: (1) single and collective cell migrations, (2) cell deformation and orientation, (3) decrease of cell-to-cell separation distances, and (4) cell growth. Herein, an attempt is made to discuss and connect various multi scale modeling approaches on a range of time and space scales which have been proposed in the literature in order to shed further light to this complex course-consequence phenomenon which induces the anomalous nature of energy dissipation during the structural changes of cell aggregates and matrix quantified by the damping coefficients (the orders of the fractional derivatives). Deeper insight into the matrix partial disintegration within the boundary layers is useful for understanding and minimizing the polymer matrix resistance stress generation within the interface and on that base optimizing cell growth.

Physico-Chemical Characteristics and Sensory Quality of Dry Fermented Sausages with Flaxseed Oil Preparations

Abstract The aim of this study was to determine the extent of changes in physico-chemical and sensory properties of dry fermented sausages where pork backfat was partly replaced by flaxseed oil used as liquid (FXL), after encapsulation (FXE), and pre-emulsified with alginate (FXA) and soy protein isolate (FXI). During production and storage, similar pH values of all products were observed. FXL sausages had significantly lower (p<0.05) weight loss which led to significantly higher moisture content, significantly lower fat content, hardness and chewiness. Also, FXL sausages had the lowest grades in terms of sensory attributes, such as colour, odour, taste, texture and overall acceptability. Flaxseed oil preparations affected the parameters of instrumental colour analysis of sausages. All modified products had significantly higher yellowness (relative to control) and FXI sausages relative to other modified products. Regarding consumer sensory evaluation, FXA sausages stood out among modified products because all other modified products had significantly lower grades relative to control. The thirty-day storage period did not lead to significant changes (p>0.05) in any of the observed sensory characteristics.

Microencapsulation of anthocyanin-rich black soybean coat extract by spray drying using maltodextrin, gum Arabic and skimmed milk powder

Abstract Black soybean coat is insufficiently valorised food production waste rich in anthocyanins. The goal of the study was to examine physicochemical properties of spray dried extract of black soybean coat in regard to carrier materials: maltodextrin, gum Arabic, and skimmed milk powder. Maltodextrin and gum Arabic-based microparticles were spherical and non-porous while skimmed milk powder-based were irregularly shaped. Low water activity of microparticles (0.31–0.33), good powders characteristics, high solubility (80.3–94.3%) and encapsulation yields (63.7–77.0%) were determined. All microparticles exhibited significant antioxidant capacity (243–386 μmolTE/g), good colour stability after three months of storage and antimicrobial activity. High content of total anthocyanins, with cyanidin-3-glucoside as predominant, were achieved. In vitro release of anthocyanins from microparticles was sustained, particularly from gum Arabic-based. These findings suggest that proposed simple eco-friendly extraction and microencapsulation procedures could serve as valuable tools for valorisation and conversion of black soybean coat into highly functional and stable food colourant.

Novel approaches in nanoencapsulation of aromas and flavors

Abstract In recent years, people’s dietary habits become more oriented toward healthy, safe, and, at the same time, tasty food. The perception of food taste is mostly affected by the addition of flavors and aromas during processing. Due to sensitivity of flavors and aromas in their native form, aroma encapsulation is already well established in the food industry. The benefits ascribed to encapsulation are reflected in easier handling of liquid flavors by its conversion into a dry form, improved stability when exposed to oxygen, light, and/or elevated temperatures, improved shelf-life, decreased release of volatile flavor components, masking of off-flavors and off-tastes, ability to impact textural properties of final products, and prolonged/controlled release. Among numerous encapsulation methods, spray drying has been predominantly used for encapsulation of flavors and aromas. However, the innovations in the field of encapsulation, particularly galloping nanotechnologies, have gained considerable attention from the food sector in the past decade, with applications for aromas as well as for other food compounds. This chapter reviews the current state of knowledge on nanoencapsulation of aromas and flavors, overviewing the processes and techniques utilized for coacervation, nanoprecipitation, molecular inclusion, and production of nanoparticulate formulations such as nanoemulsions, liposomes, solid–lipid nanoparticles (SLNs), and nanostructure lipid carriers (NLCs). Furthermore, the chapter gives insight into physicochemical and morphological characteristics of aroma nanoencapsulates, summarizing advantages and limitations of aroma nanoscale formulations versus microparticle formulations produced by conventional microencapsulation technologies. Finally, a critical prospect of potential application of aroma nanoencapsulates in real food products will be given, supported by examples available in literature.