Incorporação de curcumina em hidroxissal lamelar de zinco

Abstract

Curcumin is a yellow-orange pigment extracted from turmeric and has several functional characteristics, including antioxidant, anticancer, anti-inflammatory and antiaging properties. Its use in the food industry is restricted, as curcumin has great instability to temperature, oxygen, light and humidity. Therefore, in order to protect curcumin and improve its stability, thus avoiding the loss of its characteristics such as color and bioactive properties, the objective of this work was to produce intercalated and adsolubilized curcumin in zinc lamellar hydroxysalts (HSL) using the techniques of coprecipitation and co-adsorption, respectively, evaluating its chemical and physical-chemical characterization. To characterize the compounds, vibrational spectroscopy in the infrared region (FTIR), X-ray diffraction (DRX), thermogravimetric analysis (TGA), instrumental measurement of color and antioxidant activity by total phenolics and DPPH were performed. After intercalation of curcumin and adsolubilization, the solids were characterized. Curcumin intercalated in lamellar zinc hydroxysalt (HSL/CUR) was evidenced with a basal distance of 22.62 Å by Brag's Law, with widening of characteristic bands of curcumin and thermal improvement being observed, and from the thermogravimetric analysis it was possible to estimate the general formula of the compounds, being Zn5(OH)8(NO3)1,97(Curcumin)0,03.1,92H2O. Curcumin adsolubilized in lamellar hydroxysalt previously intercalated with vitamin B3 (HSL/B3) and in double lamellar hydroxide (HDL/B3) was also evidenced with an increase in the basal distance of 22.62 Å and 17.59 Å, respectively. However, there was no thermal improvement in the curcumin adsolubilized in HDL/B3, only in the one adsolubilized in HSL/B3. Therefore, a natural dye with thermal improvement was obtained by the curcumin intercalation method in HSL and by the curcumin adsolubilization method in HSL/B3. The obtained dyes did not oxidize during the processes, preserving their color, and did not lose their antioxidante Properties.