Microencapsulation of Cymbopogon citratus D.C. Stapf Essential Oil with Spray Drying: Development, Characterization, and Antioxidant and Antibacterial Activities.

This study aimed to microencapsulate Cymbopogon citratus essential oil (CCEO) with spray drying using maltodextrin and gelatin. The effects of the operational conditions (inlet temperature (130-160 °C), CCEO concentration (5-15%), maltodextrin concentration (10-20%)) on the physicochemical stability and antioxidant and antibacterial activities of the CCEO microcapsules were determined. The CCEO microencapsulation process had yield and encapsulation efficiency values varying from 31.02 to 77.53% and 15.86-61.95%, respectively. CCEO microcapsules had antibacterial effects against Staphylococcus aureus and Escherichia coli with minimum inhibitory concentration varying from 10 to 20%, and total phenolic contents and antioxidant activities varying from 1632 to 4171.08 µg TE/g and 28.55-45.12 µg/g, respectively. CCEO microcapsules had average diameters varying from 5.10 to 10.11 µm, with spherical external structures without cracks and apparent pores. The best desirable process conditions for CCEO microencapsulation were process inlet temperature of 148 °C, maltodextrin concentration of 15%, and CCEO concentration of 10%. The results showed that CCEO microcapsules with increased stability and low degradation of active components can be prepared by spray drying using maltodextrin and gelatin with the production of microcapsules, which could be exploited as potential food preservatives.

Lemongrass (Cymbopogon citratus DC. Stapf) essential oil microparticles: Development, characterization, and antioxidant potential.

Maltodextrin (DE 20) and gelatin (4:1, w/w, respectively) were investigated as encapsulant materials for lemongrass (Cymbopogon citratus DC. Stapf) essential oil microencapsulation by freeze-drying. Three formulations were prepared: M1 (5% essential oil), M2 (10% essential oil), and M3 (15% essential oil), all in w/w. Microparticles were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, water activity measurement, thermogravimetric and derivative thermogravimetric analysis, differential scanning calorimetry, and antioxidant activity analysis. Yield and microencapsulation efficiency were also determined. The results showed the promising potential of maltodextrin and gelatin as encapsulants and confirmed the feasibility of preparing C. citratus essential oil microparticles by freeze-drying. Microencapsulation improved the oil's thermal and oxidative stability, providing protection from volatilization and environmental conditions. Scanning electron microscopic examination of M1 revealed a closed, pore-free surface. M1 had higher yield and microencapsulation efficiency, showing great commercial potential for its reduced storage, transport, and distribution costs.

Carnauba wax as a wall material for urea microencapsulation.

BACKGROUND: The high ureolytic activity of rumen microbiota is a concern when urea is used in ruminant feed, because it leads to fast urea conversion, resulting in possible intoxication and lower nitrogen utilization. This study intended to microencapsulate urea using carnauba wax to obtain slow-release systems in the rumen. The experiment was conducted in a randomized block design, arranged in a 3 × 2 factorial, with the urea encapsulated with carnauba wax in ratios of 1 : 2; 1 : 3, and 1 : 4 (UME 2; UME 3, and UME 4) and two particles sizes (small, PS ; and large, PL ). RESULTS: All formulations showed excellent properties, including inhibition of urea hygroscopicity. The formulation UME 2 exhibited the greatest yield (91.6%) and microencapsulation efficiency (99.6%) values, whereas the formulation UME 4 presented the greatest thermal stability (259.5 °C) and lowest moisture content (1.81%). The UME 2 formulation presented a slower release than the other UME formulations studied. CONCLUSION: The production of urea microspheres using carnauba wax was successful for all microencapsulated systems developed, evidencing the promising potential for use in ruminant animal diets. The UME 2 formulation with large particles is the most recommended because it permitted greater resistance to microbial attack, allowing a slower release of urea into the rumen, reducing the risk of intoxication or ruminal alkalosis. © 2018 Society of Chemical Industry.

Physical factors affecting plasmid DNA compaction in stearylamine-containing nanoemulsions intended for gene delivery.

Cationic lipids have been used in the development of non-viral gene delivery systems as lipoplexes. Stearylamine, a cationic lipid that presents a primary amine group when in solution, is able to compact genetic material by electrostatic interactions. In dispersed systems such as nanoemulsions this lipid anchors on the oil/water interface confering a positive charge to them. The aim of this work was to evaluate factors that influence DNA compaction in cationic nanoemulsions containing stearylamine. The influence of the stearylamine incorporation phase (water or oil), time of complexation, and different incubation temperatures were studied. The complexation rate was assessed by electrophoresis migration on agarose gel 0.7%, and nanoemulsion and lipoplex characterization was done by Dynamic Light Scattering (DLS). The results demonstrate that the best DNA compaction process occurs after 120 min of complexation, at low temperature (4 ± 1 °C), and after incorporation of the cationic lipid into the aqueous phase. Although the zeta potential of lipoplexes was lower than the results found for basic nanoemulsions, the granulometry did not change. Moreover, it was demonstrated that lipoplexes are suitable vehicles for gene delivery.