Direct encapsulation of small molecule hydrophilic and hydrophobic actives in alginate microspheres using a novel impinging aerosols method

Encapsulation of pomegranate polyphenols by ionic gelation: Strategies for improved retention and controlled release

This study aimed at producing pectin hydrogel beads by ionic gelation proce to carry pomegranate extract (PE) evaluating approaches to increase its retention and protect the polyphenols from environmental conditions that interfere in the stability and color of these compounds, such as the pH of the medium. Several strategies were tested to reduce the mass transfer and consequently increase its retention. The insertion of a filler (gelatinized starch), the employment of different concentrations from the external environment, the adsorption using blank pectin-starch beads, and the electrostatic coating using chitosan were performed. The release of entrapped compounds over time was employed to evaluate the release pattern of PE in water media. Diffusion coefficients calculated from these experiments were then used to estimate the PE release behavior. The encapsulation efficiency (EE) was significantly improved (42 % to 101 %) when equalizing the concentration of the external medium with that from the beads formulation. Furthermore, the increase in the PE concentration was proportional to the rise in the mechanical strength (MS) of the beads which indicates a modification of internal structure due to the presence of polyphenols. The adsorption was efficient in entrapping the active compound, and despite the high PE content observed for all beads (average value of 2960.26 mg of gallic acid equivalent/100 g sample), they had the lowest diffusion coefficient from the release in water media. Finally, the coating was able to reduce the release rate in most of the tests (DAB uncoated = 0.5 DAB coated), however, during the electrostatic deposition a loss of about 32 % of the phenolic compounds in the chitosan solution was observed which led to a reduced EE. Despite the obtention of retarded release, coating studies need to be improved. Some adjustments in the execution of this technique are necessary so that the losses are reduced and the process becomes viable for the use of beads in food.

Application of sodium alginate extracted from a Tunisian brown algae Padina pavonica for essential oil encapsulation: Microspheres preparation, characterization and in vitro release study

In recent years, there has been considerable interest in essential oils encapsulation and in developing biodegradable microparticles. The aim of this present work was to prepare clove essential oil loaded microspheres, by a modified emulsification method, using sodium alginate extracted from a Tunisian Brown seaweed Algae Padina pavonica as biopolymer. The obtained microparticles were characterized by FT-IR, DSC and SEM. Loading capacity yield, encapsulation efficiency (%EE) and in vitro release of the essential oil were also investigated. Sodium alginate microspheres were successfully prepared as confirmed by physico-chemical characterizations. %yield of microspheres and %EE of essential oil were 72.73% and 24.77% ± 7.47%, respectively. SEM showed pseudospherical microspheres with rough surface ranging, in size, from 1500 μm to 3000 μm. In vitro dissolution study indicates a controlled released of the essential oil which follows, mainly, classical Fickian diffusion. Thus, this present work highlighted the potential of this polysaccharide as a biopolymer to formulate polymeric microspheres.