Evaluation of the effect of roasting process on the energy transition and the crystalline structures of Arabica, Robusta, and Liberica coffee from Jambi Indonesia

The effect of the roasting process has been evaluated to determine of the energy transition and the crystalline structure of three types of coffee, Arabica, Robusta, and Liberica coffee both green and roasted coffee with the roasted temperature at 200°C and 230°C. The crystalline structure of the coffee was evaluated with X-ray powder diffraction (XRD). The result exposes that the three types of green coffee showed that an amorphous structure whereas the roasted coffee denotes a crystal structure of sucrose. The varied temperature in the roasting process leads to changes in the crystal structure shown by the peak shift of 2θ for all types of coffee. The added cations, such as Fe²⁺, Ca²⁺, and Mg²⁺ ions on Liberica coffee induced of changes in the crystal structures, which are assigned by the peak shift, that imply of metal ions of the sucrose complexes happened in the solution, except for the addition of Mg²⁺ ion. (paper)