Nanoparticles of Betalain-Gelatin with Antioxidant Properties by Coaxial Electrospraying: Preparation and Characterization

Betalains are bioactive compounds with attractive antioxidant properties for the food industry, endowing them with potential application in food coatings to maintain quality and extend shelf life. However, they have low stability to factors such as light, temperature, and humidity. An alternative to protect bioactive compounds is nanoencapsulation; one of the most used techniques to produce an encapsulation is coaxial electrospraying. In this research, the preparation and characterization of gelatin-betalain nanoparticles were carried out using the coaxial electrospray technique. Betalains were extracted from pitaya (Stenocereus thurberi) and encapsulated in gelatin. The obtained material was evaluated by SEM, FTIR, TGA, and DSC techniques and for its antioxidant capacity. By SEM, nanoparticles with spherical and monodisperse morphologies were observed, with betalain concentrations of 1 and 3% w/v and average diameters of 864 and 832 μm, respectively. By FTIR, the interaction between betalain and gelatin was observed through amino groups and hydrogen bonds. Likewise, the antioxidant activity of the betalains was maintained at the time of encapsulation, increasing the antioxidant activity as the concentration increased. The results of the DPPH, ABTS, and total phenols methods were 645.4592 μM T/g, 832.8863 ± 0.0110 μM T/g, and 59.8642 ± 0.0279 mg GAE/g for coaxial nanoparticles with 3% betalains, respectively. Therefore, the coaxial electrospray technique was useful for obtaining nanoparticles with good antioxidant properties, and due to the origin of its components and since the use of toxic solvents is not necessary in the technique, the material obtained can be considered food grade with potential application as a coating on functional foods.

Preparation and Characterization of Extruded Composites Based on Polypropylene and Chitosan Compatibilized with Polypropylene-Graft-Maleic Anhydride

The preparation of composites of synthetic and natural polymers represent an interesting option to combine properties; in this manner, polypropylene and chitosan extruded films using a different proportion of components and polypropylene-graft-maleic anhydride (PPgMA) as compatibilizer were prepared. The effect of the content of the biopolymer in the polypropylene (PP) matrix, the addition of compatibilizer, and the particle size on the properties of the composites was analyzed using characterization by fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), tensile strength, and contact angle, finding that in general, the addition of the compatibilizer and reducing the particle size of the chitosan, favored the physicochemical and morphological properties of the films.

Thermoluminescence response of new KCl(X)Br(1-X):EuCl3 sintered phosphors exposed to beta and gamma radiation

Alkali halides crystals have been the subject of intense research for an understanding of their radiation-induced defects and luminescence properties. They exhibit noteworthy thermoluminescence (TL) properties when exposed to ionising radiation. Currently, these materials are grown employing expensive and rather complicated techniques. In this work, the results on the TL properties of new alkali halides phosphors fabricated by a simple and inexpensive procedure are presented. The samples were made by mixing KCl, KBr and EuCl3 salts, and compressing them at a pressure of 3.2 x 10(7) Pa during 3 min, followed by sintering at 700 degrees C during 24 h under air atmosphere. The dosimetric response of the samples showed an increase with radiation dose in the 1.5-20.0 Gy dose range for beta and gamma radiation. The TL glow curves in sintered samples presented significant differences in their peak structures compared with monocrystalline samples, indicating that the nature of the trapping states and the recombination mechanisms may be different.