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.

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.

Microencapsulation of sweet orange essential oil (Citrus aurantium var. dulcis) by liophylization using maltodextrin and maltodextrin/gelatin mixtures: Preparation, characterization, antimicrobial and antioxidant activities.

This study evaluated maltodextrin (MD) and gelatin (GEL) in different ratios (SO1, MD only; SO2, MD and GEL = 2:1; and SO3, MD and GEL = 1:1, respectively) as wall materials to microencapsulation of sweet orange essential oil (SOEO, 10% w/w). SOEO microspheres were obtained by emulsification/lyophilization and characterized regarding the microencapsulation yield and efficiency, infrared spectroscopy, ultrastructural aspects (scanning electron microscopy, SEM), thermogravimetric (TG), derivative thermogravimetry (DTG) and differential exploratory calorimetry (DSC) and bioactive properties. Yield and SOEO microencapsulation efficiency (MEE) was of up to 90.19 and 75.75%, respectively. SEM analysis showed SO1, SO2 and SO3 microspheres with irregular shapes. Although improvements in thermal stability of all formulated microspheres were observed, TG and DTG curves indicated slower rates of volatilization and degradation of SOEO in SO1. DSC curves indicated that SO1, SO2 and SO3 microsphere formulations were effective in protecting SOEO, especially in relation to improvements in oxidative stability. Antibacterial and antioxidant properties, as well as total phenolic content of SOEO, were maintained in all formulated microspheres. SOEO microspheres can be prepared using MD and GEL and lyophilization, resulting in high yields, MEE, stability and preservation of antioxidant and antimicrobial properties.