Cera de carnaúba na microencapsulação de ureia para liberação lenta.

Abstract

The objective was to use the carnauba wax to encapsulate the urea in order to elaborate a slow release system. Three microencapsulated systems were obtained by the Lyophilization technique, with different ratios between encapsulant and core (1:2, 1:3 and 1:4). The products were evaluated for the mycoencapsulation process through the performance and efficiency analysis, besides characterized by techniques of Thermogravimetry, Exploratory differential calorimetry, Determination of moisture and water activity, determination of charge, Spectroscopy in the infrared region and Electron microscopy of scanning. In situ degradation kinetics, nitrogen release profile and nucleus release mechanism were evaluated in small ruminants. The formulations did not differ much from each other and all showed excellent properties, including inhibition of urea hygroscopicity, especially the formulation 1:2, which exhibited the highest yield values and highest microencapsulation efficiency, while the formulation 1:4 presented Higher thermal stability and lower moisture content. The production of urea microspheres using carnauba wax demonstrated successful results for all developed microencapsulated systems, evidencing the promising potential of using this regional raw material for this purpose. The kinetics showed that the increase of the wax content reduced not only degradation but also the use of urea, as can also be verified in the release profile, where UME2 showed a more controlled release than the other UMEs studied. Carnauba wax provided a higher bioavailability of urea, reducing the risk of intoxication. The main mechanisms of release were diffusion and biodegradation, a fact that prevented the complete use of N, but did not decrease the rate of release. The behavior of the granulometries studied showed that the increase of the particle size tends to regulate the rate of N release better, being more effective than adding wax to the system. Thus, it is concluded that carnauba wax is a promising alternative for the gradual release of urea, with the concentration 1:2 being the most favorable.