Abstract
Dust explosions represent a major hazard in food processing industries, particularly when dealing with organic powders. Cocoa powder, although widely produced and consumed, has received little scientific attention regarding its explosibility compared to other food powders such as flour or sugar. This work investigates the potential explosiveness of cocoa powder by analysing its chemical and physical properties and identifying the main parameters influencing ignition sensitivity. Five commercial cocoa powders were selected, and an experimental campaign consisting of thermogravimetric analysis (TGA), crystallization and melting studies using reaction calorimetry, granulometric analysis, ICP-MS for metallic content, and pH/colorimetric analysis was carried out. A Matlab-based fitting model was developed to extract kinetic constants from TGA data, while a second code was implemented to calculate the theoretical Minimum Ignition Energy (MIE) from the collected experimental data. Results show that kinetic constants, crystallization enthalpies, particle size distribution, and metallic content significantly influence cocoa powder explosiveness. In particular, the presence of potassium carbonate/hydroxide and aroma additives can alter ignition susceptibility with respect to pure cocoa powders. The correlation between metal content (notably Al and Mg), pH, and colour was confirmed, indicating that darker powders with higher alkalinity may present lower ignition sensitivity. The theoretical protocol for MIE estimation developed in this work provides a valuable predictive tool that can reduce the need for extensive practical testing, also contributing to both the understanding of cocoa powder explosiveness and the safer handling of such powders in food industries.
