Encapsulação de curcumina em fibras e cápsulas de amido de batata por mecanismos eletrohidrodinâmicos

Abstract

The encapsulation of curcumin in a low cost, abundant and biodegradable polymer matrix was addressed in this study. The objective of this work was to encapsulate curcumin at different concentrations (0, 0.5, 0.75 and 1% w/w) in fibers and capsules of native potato starch by electrospinning and electrospraying processes. Initially, different conditions for the production of fibers and capsules were evaluated, varying the polymer concentration and the resting time of the polymer solution. The conditions used for curcumin encapsulation were 20% starch/24 h and 10% starch/48 h, for fibers and capsules, respectively. Morphology and size distribution, FTIR spectra, thermal properties, encapsulation efficiency, thermal resistance, and antioxidant properties were evaluated. The production of fibers with homogeneous morphology, cylindrical and without beads was obtained with the incorporation of 0.75% of curcumin in the polymeric solutions, while the concentrations of 0.5 and 1% formed fibers with the presence of beads and uniform morphologies were observed for the capsules, regardless of the compound concentration. The starch fibers and capsules showed diameters ranging from 94 nm to 464 nm and 1183 nm to 1371 nm, respectively. The fibers and capsules loaded with curcumin had mean diameters ranging from 108 nm to 142 nm and 1373 nm to 1787 nm, respectively. The FTIR spectra indicated interactions between curcumin and starch, for both, fibers and capsules. The encapsulation of curcumin in the form of fibers or capsules increased its thermal stability, as observed by thermogravimetric curves. High efficiency of curcumin encapsulation was found for fibers with 79% and for capsules with 97% of efficiency. Curcumin encapsulated into starch fibers and capsules showed greater thermal resistance at 180ºC for 2 h, when compared to non-encapsulated curcumin. The antioxidant activity of starch fibers containing 1% of curcumin had the greatest capacity to inhibit the ABTS radical, with 45% inhibition. Native potato starch fibers and capsules incorporated with curcumin are promising materials for application in food or active food packaging, since the efficient encapsulation guaranteed the protection of this compound against heat treatment and maintained its antioxidant activity.