Comparative Study of Chocolate Cooling Supported by Computational Fluid Dynamics

The sensorial perception of dark chocolate has been studied and is commonly related to cocoa varieties’ post-harvest or manufacturing process. Although physical and chemical changes during the transformation of cocoa into chocolate are known, there is still a gap concerning the impact of heat transfer on sensory evaluation. This work aimed to apply experimental measurements and numerical simulations in a comparative study of the thermal behaviour of dark chocolate during refrigeration and evaluate its impact over physical properties and sensory evaluation. Temperature presented an initial phase with high cooling rate, shorter at 10 °C due to the higher temperature difference. After, a steady phase was observed at 10 °C, followed by a temperature decrease until 8000 s. The behaviour at 25 °C did not present such plateau, increasing from 27.1 °C to 27.5 °C, a consequence of the dissipation of latent heat during phase transition and the short temperature gradient. Numerical simulations were more correlated to experimental data at 25 °C, presenting a temperature difference < 2 °C. The instrumental evaluation of appearance presented a higher luminance of chocolate surface at 25 °C cooling temperature, which may indicate a higher propensity for occurring fat bloom during storage. Sensory evaluation revealed no significant differences on appearance, texture, and flavour/aroma between cooling at 10 °C and 25 °C.