Thermal Transport Kinetics of Potato Croquettes During the Frying Process

Heat and mass transfer behaviour of frozen cylindrical potato croquettes was investigated during the deep-fat frying process at different oil temperatures (150, 160, 170, and 180 °C) and times (540, 420, 300, and 240 s), using the product’s actual geometry to better represent real frying conditions. The apparent effective heat transfer coefficient (he), effective moisture diffusivity (De), and effective mass transfer coefficient (ke) were estimated experimentally. Increasing oil temperature led to a gradual decrease in he, whereas De and ke increased consistently across the investigated range. The calculated he values ranged from 82.980 to 119.86 W m−2 °C−1, while De and ke varied between 1.237 × 10−6–1.331 × 10−6 m2s−1 and 6.189 × 10−6–13.312 × 10−6 m s−1, respectively. The time-dependent behaviour of the transport parameters was further analyzed using pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models. Statistical evaluation based on R2 and RMSE showed that PFO best described he, whereas PSO provided superior agreement for De and ke. These results demonstrate that heat and mass transport during frying are dynamic processes that can be quantitatively characterized using simplified kinetic formulations, offering a practical engineering tool for process prediction and optimization.