Release of phenolic compounds from fermented cocoa powder during fast heating in a novel hot plate reactor.

This article studies the release of phenolic compounds during cocoa heating under vacuum, N2, and air atmospheres, and proposes fast heating (60 °C • s-1) as a methodology that allows the release of polyphenols from fermented cocoa powder. We aim to demonstrate that gas phase transport is not the only mechanism to extract compounds of interest and that convective-type mechanisms can facilitate the process by reducing their degradation. The oxidation and transport phenomena were evaluated both in the extracted fluid and in the solid sample during the heating process. Polyphenols transport phenomena were assessed based on the fluid (chemical condensate compounds) that was collected cold with an organic solvent (methanol) in a hot plate reactor. Out of all the polyphenolic compounds present in cocoa powder, we assessed specifically the release of catechin and epicatechin. We found that high heating rates combined with vacuum or N2 favor the ejection of liquids; then, it is possible to extract compounds such as catechin-which is dissolved/entrained and transported in the ejected liquids-and avoid degradation phenomena.

Co-gasification and co-combustion of industrial solid waste mixtures and their implications on environmental emissions, as an alternative management.

The primary sludge produced by the wastewater treatment plant of a pulp and paper mill has high physicochemical heterogeneity, which limits the efficiency of thermochemical methodologies for the final disposal of this residue. As a solution, co-pelletization of the Primary Sludge (PS) with two other principal Industrial Solid Residues (ISRs) of the plant, Coal Boiler Ashes (CBA) and Wood Waste chips (WW), was proposed as a way to valorize the PS for energy use, while reducing dewatering costs. The energy potential was evaluated through a series of thermal co-processing tests of disaggregated and pelletized mixtures. Due to their differing fixed-carbon-to-volatile-material ratios, combining the ISRs resulted in a reduction of up to 45% of the mass of the ISR generated, improving the disposal conditions and achieving a minimum thermal power of 5.0 MJ/Nm3 through gasification. Finally, the environmental implications of the thermal co-processing of the wastes were assessed, finding very low impacts due to pollutant emissions, in accordance with the legal environmental regulations in force in Colombia.