RESUMO
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.
Assuntos
Antioxidantes/química , Cymbopogon/química , Microesferas , Óleos Voláteis/química , Liofilização , Gelatina/química , Polissacarídeos/químicaRESUMO
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.