Chemical composition and flavour development of cocoa products by thermal and enzymatic technologies

A novel technology to process traditional chocolate-making ingredients has been investigated with the main objective to promote the generation of key chocolate odorant volatiles as a part of the commercial interest of the industrial partner to create a new line of natural products with intense chocolate flavour. The novel technology is based on the thermal generation of flavours (non-enzymatic browning) using a closed-batch reactor that is able to hold six bars of overpressures, speeding up the aromatic reactions, and the use of enzymes to increase the flavours precursors. Pilot scale experiments were carried using sugars, cocoa powder and water in various ratios and were submitted to temperatures from 70°C to 130°C during various reaction times (1 to 10 hours) reaching over pressures from 0.2 to 3.5 bars. The assessment of the evolution of the products obtained was carried out chemically and sensorially. Chemically, using a laboratory-developed headspace solid phase microextration gas chromatography mass spectrometry (HS-SPME-GC-MS) methodology and sensorially with a trained panel of tasters. Temperatures of 130°C with enzymatic pre-treatment of the cocoa resulted with the highest generation of volatiles scoring the maximum in the aromatically but on the other hand 90°C, without enzymatic pre-treatment, had the best taste evaluation