Roasting impact on the chemical and physical structure of Criollo cocoa variety (Theobroma cacao L)

This work analyzed the effect of infrared roasting at 100, 150, and 200 degrees C on the main physical and chemical changes of cocoa. Raw and roasted cocoa were analyzed using Brunauer-Emmett-Teller, Fourier transform infrared spectroscopy, modulated differential scanning calorimetry (MDSC), thermogravimetric analysis (TGA), SPME, and GC-MS. Using MDSC, the fusion of fat at around 35 degrees C, and the desolvation of water and volatile compounds were identified. TGA detected loss of mass of various groups of chemical compounds, including those present pre-roasting and generated during roasting. The unroasted cocoa's total sugar content of 2.71% decreased to 0.64% when roasted at 200 degrees C, whereas roasting at 200 degrees C generated seven (7) pyrazines. Tetramethylpyrazine is the most abundant, reaching the highest concentration when roasted at 150 degrees C, but decreases when roasted at 200 degrees C, due to the high temperature. To obtain the maximum production of favorable pyrazines, the temperature must be controlled based on the quality objectives of the final product. Practical applications The process of roasting cocoa is of great importance to the chocolate and derivatives industry. Knowledge of the chemical and physical changes that occur during roasting can help to optimize the operating conditions to obtain a better-quality product, in particular by conserving and developing the flavor and aroma of fine Criollo cocoa varieties. This will support the industrialization of fine cocoas, presenting an option for improving the economic and social development of marginalized countries and communities.