Synthesis of an adsorbent-bioactive complex with antioxidant properties: Thermal stability.

Bioactive compounds from jaboticaba peel were adsorbed on microcrystalline cellulose isolated from sorghum bagasse (MCC) to maintain their antioxidant activities (AA), as they are sensitive to pH, temperature, light, and the presence of oxygen. For this reason, there are limitations to keeping them active during storage or industrial processing, and new processes need to be studied. The synthesis conditions of the adsorbent-bioactive complex formed by the adsorption process of total phenolic compounds (TPC) in MCC and their stability against temperature variation (90–130 °C) were analyzed. In the synthesis of the complex, it was observed that in the kinetic study, pseudo-second order model fitted the experimental data, and in the equilibrium isotherms, the Langmuir model best describes the synthesis. The thermodynamic parameters (ΔG ads , ΔS ads , and ΔH ads) showed that TPC interacts with MCC by chemical adsorption through a spontaneous and exothermic process. Approximately 90% of the TPC was released in the first 60 min of the aqueous desorption process. In the thermal stability study, the complex reduced the degradation of TPC and AA compared to jaboticaba peel powder, reaching a percentage of reduction in its degradation of 71% at a temperature of 130 °C. [Display omitted] • A way to stabilize total phenolic compounds in microcrystalline cellulose is presented. • Thermodynamic study showed that TPC interacts with MCC by chemical adsorption through a spontaneous and exothermic process. • The complex reduced the thermal degradation of total phenolic compounds in 71% at the temperature of 130 °C. • The complex reduced by approximately 58%, 52% and 31,8 the degradation by the DPPH, ABTS and FRAP assays. • The complex can be used in industrial processes that use high temperatures without losing its functional characteristics. [ABSTRACT FROM AUTHOR]