Asian Journal of Research and Review in Agriculture

Preserving fish, a highly perishable commodity with ~80% moisture content, demands efficient drying technologies to maintain nutritional quality and extend shelf life. This study optimized a newly developed rotary cage-tray fish dryer, designed with dual heat sources (charcoal-wood and gas) with a mechanized turning system, to enhance process efficiency and product quality during catfish (Clarias gariepinus) drying. Using an I-Optimal response surface experimental design (version 10), 48 runs were conducted with six input factors; gas pressure (kPa), fish length (cm), fish weight (kg), number of turns, charcoal-pot load, and fish appearance alongside six responses: drying time, physical appearance, taste and flavor, drying rate, mean temperature and drying efficiency. Optimal operating conditions were determined as: gas pressure (1.109 bar), fish length (24.733 cm), fish weight (0.979 kg), number of turns (6), and charcoal-pot load (two-third filled), yielding a curved fish appearance. Desirability values ranged from 0.672 to 0.683, reflecting robust optimization outcomes. Confirmation experiments validated the model, with predicted and actual response values showing low standard deviations (e.g., drying time SD < 0.5 h) and errors (<2%), affirming high predictive accuracy. The optimized system reduced drying time by 15–20% compared to baseline settings and improved sensory attributes (taste, flavor) by minimizing over exposure to heat. This work demonstrates the efficacy of surface response methodology in fine-tuning complex drying systems, offering a data-driven approach to balance efficiency and quality in fish preservation.