Development and optimization of general drying models for cod (Gadus spp.) using supercritical carbon dioxide

This study aimed to investigate the supercritical carbon dioxide (SC-CO2) drying of cod (Gadus spp.) by developing and optimizing a general mathematical drying model. We applied a central composite rotatable design (CCRD) considering the time (180–360 min), temperature (35–45 °C), and CO2 flow rate (15–25 kg/h) as independent factors, aiming at the reduction of moisture and water activity (aw) of Gadus morhua. Time and flow rate (FR) were the main factors affecting the moisture and aw responses. The mathematical models developed were validated with the accuracy and bias factors and generalized using Gadus chalcogrammus samples, resulting in the acceptable range of 1.003–1.121. The optimal parameter values for drying performance were 312.38 min, 45.38 °C, and 27.4 kg/h (R2 = 0.999). Our results suggest a promising application of SC-CO2 as a fish drying technology, describing a generalist-validated and optimized SC-CO2 drying model for Gadus spp.