Drying kinetics and color changes of anchovies in solar and open sun drying

Abstract The drying process is a critical heat treatment widely used in the food industry due to the increasing global demand for dried foods. Anchovies, being highly perishable yet nutritionally valuable, require effective drying to extend their shelf life. This study aimed to evaluate the impact of three drying methods namely, open sun drying (OSD), solar greenhouse tunnel dryer (GTD), and forced convective solar dryer (FCD) on the drying kinetics and color changes of anchovies. A total of 20 kg of anchovies were dried using each method to compare drying rates, moisture content, and color kinetics. Results revealed that GTD achieved the highest drying rate and required the shortest drying time (6 h), compared to 9 h for OSD and FCD. The drying rate was dependent on moisture content, and the Henderson and Pabis model accurately described the moisture ratio of anchovies dried using OSD. In contrast, the Midilli et al. model best fitted the moisture ratio data for GTD and FCD. The lightness (L*) of dried anchovies exhibited the highest reduction in GTD, followed by FCD and OSD, with a first-order kinetic model effectively fitting the lightness data. Effective moisture diffusivity values were 6.43737 × 10–10, 7.44735 × 10–10, and 1.02148 × 10–09 m2/s for OSD, FCD, and GTD, respectively. This study highlights the advantages of solar drying methods, particularly GTD, in enhancing drying efficiency, reducing drying time, and preserving product quality.