Compostos fenólicos obtidos da pirólise de resíduos de café

Abstract

Phenolic compounds are present in great abundance in nature including coffee biomass. The residue resulting from the processing of coffee is equivalent to a large quantity in mass, comprising bark, pulp and sludge, and being primordial its reutilization in attention to the use of biomass by an environmentally correct alternative. In the present work we intend to evaluate the formation and obtaining of phenolic compounds using pyrolysis as a transformation process. The green, arid and black coffee beans (Coffea arabica) were used as sample, being submitted to pyrolysis with entrainment of N2 gas and condensation by cooling. The condensed portions were collected at temperatures of 250°C, 500°C and 650°C in order to select classes of components according to the molecular breaks and volatilization of these components. Once the phenolic compounds had ionizable groups and differences in solubility, each of the condensed samples were extracted with dichloromethane and ethyl acetate using pH modifiers and analyzed by methods capable of identifying and quantifying the phenolic constituents using complementary techniques of liquid chromatography, total determination of wet phenolic compounds and IR spectroscopy. The methods of analysis confirmed the presence of fatty acids and provided the verification of some phenolic compounds: chlorogenic acids, gallic acid, catechin, t-cinnamic acid, rutin, trigonelline and caffeine. It was evidenced the presence of different phenolic compounds in the 3 ranges of pyrolysis temperatures collected. The total content of phenolic compounds was obtained, demonstrating that the pyrolysis process performed presents about 1% of yield, indicating an alternative to the use of biomass as a focus on lignin.