Experimental study and modelling of heat and mass transfers in cashew nuts during steaming and drying operations

Résumé fourni par la source

Cashew nut shelling can be a difficult operation due to the presence of cashew nut shell liquid (CNSL), the kidney-shaped shell morphology, and the fragility of the kernels, all contributing to a high proportion of broken kernels. Improving the yield of whole kernels requires a thorough understanding of the process. This study aimed to characterize liquid water and water vapor transport during soaking, steaming, and drying operations, which precede and facilitate shelling, and to develop a dynamic model to simulate these phenomena. Water and gas (vapor and air) transport pathways were identified using controlled pressurization and partial sealing experiments. A two-compartment model incorporating a preferential pathway through the hilum was used to simulate the transfer mechanisms. Experimental validation was conducted using the temperature and moisture content kinetics measured during steaming (100 °C) and drying (60 °C, 11 ± 2% RH, 2 m/s). The results indicate that the shell surface, including the hilum, dehiscence line, and peduncular pore, is the primary route for water and gas (vapor and air) transport. The model exhibited good predictive capabilities, with adjusted R² values of 0.994 and 0.992 for moisture content and temperature, respectively, during steaming, and 0.723 and 0.985, respectively, during drying.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.