Thermal analysis of coffee beans of Castilla variety grown in Colombia

This article presents the main results achieved after thermally characterizing coffee beans of the Castilla variety. Such beans were produced in the Southeastern region of Santander, Colombia. Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) tests were carried out. We determined various stages of thermal degradation within the beans, along with their thermal transitions. We also determined the variation of calorific capacity throughout the process. Thermal characterization allowed us to carry out an analysis of the resulting gases, using infrared (IR) spectroscopy. We check the resulting experimental data against the Bruker IR database. We were able to detect three sectors within the coffee bean that exhibited mass loss, for a heating rate of 5°C/min, and for temperatures up to 1000°C. Zones were in the following regions: 58.5°C and 324°C, with a mass loss of 50.26%; 324°C and 432°C, with a mass loss of 14.67%; and 432°C and 513°C, with a mass loss of 4.46%. Residual mass was of 24.11%. We obtain similar data with tests at a rate of 10°C/min. We deem this information as relevant for coffee production, especially in those processes related to local production. Similarly, for the start of the characterization of this Castilla variety produced in a well-defined regions of Colombia.

Keywords: Thermochemical properties of coffee, thermogravimetric analysis, differential scanning calorimetry, infrared analysis.