Lisina microencapsulada em matriz lipídica das ceras de abelha e de carnaúba enriquecida com tanino da Mimosa tenuiflora: caracterização e degradabilidade.

Abstract

The objective was, through the emulsification and oven drying technique, to form systems containing lysine (Lys) as (core) microencapsulated in a lipid matrix of beeswax (BW) and carnauba wax (CW) (wall material), enriched with tannin from Jurema Preta (TJP). The microencapsulated systems were characterized in terms of microencapsulation yield (MY), microencapsulation efficiency (ME), differential scanning calorimetry (DSC) and by scanning electron microscopy (SEM) techniques. Degradability was evaluated in vitro (DaisyII ANKOM) and in situ (animals fistulated in the rumen), both were conducted in non-woven fabric (NWF) bags with dimensions of 5 x 5 cm containing 2 g of sample and the Incubation times were (0; 15; 30; 60; 120; 180; 1440 and 2880 min), for which ruminal parameters were also investigated. MY results were 75.66; 77.46; 78.48; 79.46% for BW+Lys+0TJP; BW+Lys+1TJP; BW+Lys+2TJP; BW+Lys+3TJP respectively and 80.15; 84.10; 84.29; 84.47 for CW+Lys+0TJP; CW+Lys+1TJP; CW+Lys+2TJP; CW+Lys+3TJP respectively. The ME results were 81.06±0.48; 81.30±0.59; 84.69±1.29; 85.17±0.97 for BW+Lys+0TJP; BW+Lys+1TJP; BW+Lys+2TJP; BW+Lys+3TJP respectively and 79.12±1.18; 85.17±1.99; 87.35±3.12; 89.28±3.87 corresponding to CW+Lys+0TJP; CW+Lys+1TJP; CW+Lys+2TJP; CW+Lys+3TJP. The DSC results for BW presented an endothermic event (Event 1) at 68 °C, related to its melting and another endothermic event (Event 2) at 385 °C, related to its thermal degradation. CW presented an endothermic event at 82 °C, related to its melting point. Lys showed three endothermic events at 83, 264 and 309 °C. TJP presented an endothermic event at 99 °C. As for microencapsulated systems, it is observed that the events of the isolated phases (wax, Lys and TJP) were maintained or underwent some change according to the presence or absence of tannin and its increasing level. It is also verified that the microencapsulated Lys presented a higher thermal degradation temperature in relation to its free form, attesting to the protection of the BW and CW encapsulating matrices. There was no interaction between wax and tannin level (P>0.05) for degradation and retention of dry matter (DM). There was a statistical difference in DM retention between BW and CW in the incubation times (15; 1444 and 2880 min). Ruminal pH and temperature remain relatively constant throughout the incubation periods. The use of BW and CW as a lipid matrix associated with TJP as encapsulating agents presents MY and ME of Lys, and with high thermal stability. Formulations with 3% TJP, regardless of the ceride used, result in a greater amount of DM and nitrogen (N) retained in the lysine microcapsule. The encapsulation of Lys in BW and CW lipid matrix, associated with TJP results in an increase in DM and non-degraded N, both in vitro (Daisy) and in situ (fistulated animal) evaluation, and without compromising pH and rumen temperature. CW was more efficient than BW in protecting crude protein (CP) against ruminal degradation, and the in situ incubation time influenced the retention and degradation of CP in encapsulated products, regardless of TJP levels.