LIGNIN AS A POTENTIAL WALL MATERIAL TO ENCAPSULATE UVAIA (EUGENIA PYRIFORMIS) PHENOLIC EXTRACT

Uvaia (Eugenia pyriformis) is native fruit from Brazil. Its excellent nutritional quality and composition rich in phenolic compounds, especially quercetin, confers to Uvaia a huge potential for economic exploitation. However, the low solubility of quercetin in water and its degradation on the gastrointestinal tract limits its bioavailability and confers to its metabolite’s smaller bioactivity. This can be overcome by their encapsulation using natural polymers. Thus, this study aimed to develop lignin nanoparticles to encapsulate Uvaia extracts through solvent shifting method. The Uvaia extract was obtained through pressurized liquid extraction (1 hour, 70 ºC and 60.0 % ethanol) at constant pressure (10 MPa). The extraction conditions were previously defined through a 2² central composite rotational design (CCRD). Freeze-dried Uvaia extract (0, 5 and 10.0 %wt) and kraft lignin (0, 95.0, and 90.0 %wt) were added (38.5 mg.L-1) to acetone:water (3:1) and stirred overnight. After filtration, water was added to induce particle formation. Acetone was removed by rotary evaporation. Particles were characterized according to the morphology (SEM), size (DLS) and zeta potential. The encapsulation efficiency was evaluated through high-pressure liquid chromatography (HPLC). Overall, the zeta potential of particles was negative. The particle morphology showed particles with a well-defined spherical shape and homogeneous size distribution. The particle with 95.0 % lignin (wt) showed the largest size and the highest encapsulation efficiency 74.8 %. The results suggest that lignin is an efficient biopolymer to encapsulate Uvaia extracts. These findings open new possibilities for the economic exploitation of the fruit and its valorization.