Desenvolvimento, caracterização e potencial antioxidante de sistemas nanoemulsionados contendo extrato de casca de bacaba (Oenocarpus bacaba Mart.)

Abstract

Oenocarpus bacaba Mart. is a palm tree native from the amazon whose fruit processing generates the peel as a by-product that is rich in antioxidant compounds with potential to be used in the development of new food, pharmaceutical and cosmetic products. The work aimed to develop a nanoemulsified system containing bacaba peel extract, characterize it, and evaluate its stability and its antioxidant potential. The HLB (Hydrophilic-lipophilic balance) for baru oil was determined and 32 systems were developed with different proportions of water, oil and surfactants (Span 80 and Tween 80). From the various systems developed, 16 had emulsified characteristics and from these, three were selected for the incorporation of bacaba peel extract in the proportion of 0.5% (w/w). Formulations with and without extract were prepared and submitted to centrifugation, evaluation of pH, electrical conductivity and refractive index and submitted to the preliminary stability test, where only two formulations (1NEC and 1NEB) remained stable. Thus, the formulations approved in the preliminary stability test were reprepaired and submitted to the accelerated stability test for a period of 90 days at temperatures of 25 ± 1 °C, 40 ± 1 °C, 5 ± 1 °C, as well as exposed to light radiation, and the physical-chemical parameters were analyzed every 30 days. Still, the tests of the hydrodynamic droplet diameter, zeta potential, rheological profile and the analysis of the antioxidant potential were carried out. The formulations remained stable at temperatures of 25 ± 1 and 5 ± 1 °C, being unstable to light radiation and 40 ± 1 °C. The hydrodynamic diameter of the globules for the 1NEB and 1NEC formulations was compatible with that of nanoemulsions (142,9 and 198,0 nm) with a polydispersion index of 0,3, typical of monodisperse systems and zeta potential of -34,7 and - 35,1 mV providing electrostatic stability to the systems. The formulations presented rheological behavior typical of non-Newtonian pseudoplastic fluids with thixotropy, with an increase in viscosity promoted by the incorporation of the extract in the system. The extract's antioxidant potential was demonstrated by its ability to reduce the radicals DPPH (15,60 mgL-1 ) and ABTS+ (643,69 mM Trolox g-1 ) and its incorporation into a nanoemulsified system favored this action even more, showing results of 8,13 mgL-1 and 933,88 mM Trolox g-1 . It was verified the same antioxidant activity profile for the extract and formulations, that is, the lower the IC50 values, the greater the antioxidant activity equivalent in trolox. The results suggest that the bacaba peel extract has potential application in different industrial sectors such as food, pharmaceutical and cosmetic, in order to take advantage of a by-product that would otherwise be discarded.