Development of alginate/pectin microcapsules by a dual process combining emulsification and ultrasonic gelation for encapsulation and controlled release of anthocyanins from grapes (Vitis labrusca L.).

The aim of this study was to investigate the physicochemical, morphological, and gastrointestinal release properties of an anthocyanin-rich extract of grapes in alginate and pectin beads as carriers; the effects of ultrasonic gelation combined with emulsification were also investigated. In general, the alginate beads showed smaller size and more regular shape compared to pectin. The effect of emulsification combined with ionic gelation was more pronounced in the alginate beads and resulted in higher retention of anthocyanins, higher antioxidant capacity, and also allowed the best release profile during intestinal digestion. Thus, the simultaneous strategy could be an interesting delivery system and enhance the release of anthocyanins, providing an opportunity for the development of ingredients with different bioactive properties.

Effects of salts and sucrose on the rheological behavior, thermal stability, and molecular structure of the Pereskia aculeata Miller mucilage.

The rheological behavior, thermogravimetric analysis (TGA), and atomic force microscopy (AFM) of the Pereskia aculeata Miller (OPN) mucilage treated with sodium chloride (NaCl), calcium chloride (CaCl2), and sucrose were evaluated. The experimental design was divided in a fractional factorial 25-1 for the screening of factors (OPN, sucrose, NaCl, CaCl2, and pH) and then in a 5 × 3 × 3 full factorial (OPN, sucrose, and NaCl). The model solutions used for the screening of factors presented shear-thinning behavior and the OPN mucilage concentrations were the factors that had significant effect on the apparent viscosity. Sucrose addition increased the thermal stability of the OPN mucilage solutions. OPN mucilage, sucrose, and NaCl were the variables with significant effect on thermogravimetric responses. The samples presented Newtonian behavior in 0-1.25% OPN mucilage concentrations and non-Newtonian behavior adjusted by power-law in 2.50-5.00% OPN mucilage concentrations with predominance of elastic behavior, contributing to the formation of stronger gels. The presence of sucrose in the systems containing OPN mucilage changed their rheological properties and salt additions caused reduction in viscosity. The AFM results provided a better understanding of the mechanism of OPN mucilage interactions in different solutions that justify the changes in viscosities.

Ultrasound-assisted oil-in-water nanoemulsion produced from Pereskia aculeata Miller mucilage.

For the preparation of nanoemulsions, the correct choice of emulsifiers, together with the emulsification methods, directly influences the final product quality. The present study reports the ultrasound-assisted preparation of oil-in-water nanoemulsions produced with mucilage extracted from leaves of Pereskia aculeata Miller (ora-pro-nobis; OPN). The OPN mucilage (%) and soybean oil (%) concentration range, and the process operating parameters, ultrasonic power amplitude (%) and sonication time (min), were optimized based on the mean droplet diameter (d32). The effect of the mucilage and oil concentrations was also investigated by the response variables such as polydispersity, density, turbidity, viscosity, zeta-potential, and interfacial tension. The higher OPN mucilage concentrations (%) with lower amounts of soybean oil (%) favored nanoemulsion formations (116 ≤ d32 ≤ 171 nm) and increased polydispersity, density, and zeta-potential. On increasing OPN mucilage and soybean oil the turbidity of the dispersions increased. All colloidal systems showed Newtonian behavior, and the viscosity in the systems increased due to the greater OPN mucilage concentration in the aqueous phase at a certain oil concentration. In addition, lower values of equilibrium interfacial tension were found with increasing OPN mucilage concentrations. Finally, from the stability test, it can be pointed out that the OPN mucilage concentration should be between 1.0 and 1.5% and the oil concentration should be less than 5%, so that lower d32 values are maintained over time. Therefore, mucilage extracted from OPN and the ultrasound technique can be used in the preparation of nanoemulsions.