Optimization of process conditions for drying of catfish (Clarias gariepinus) using Response Surface Methodology (RSM)

Abstract

Drying is applied to lower the moisture content of fish to a level that can prevent the growth of mould and infestation of micro-organism and thus minimizes microbial degradation. The goal of this work was to optimize the process conditions during electrical oven drying of catfish. Moisture content (MC) was quantitatively investigated during the drying process of catfish sizes using response surface methodology (RSM) to obtain minimum moisture content. The independent process variables for the drying process were temperature (50–70 °C), product thickness (10–20 mm), salt concentration (0–20%) and drying time (480–600 min.). Two factorial interaction (2FI) regression model describing the effects of independent drying process variables on the moisture content was developed. The effects of temperature and drying time were more pronounced for MC than the thickness and salt concentration.The optimum conditions were found to be temperature = 63.43 °C, product thickness = 14.81 mm, salt concentration = 9.07% and drying time = 600 min. At these optimum conditions, moisture content was found to be 2.64% w.b. Validation of experimental results with the empirical model was evaluated using coefficient of correlation (R2) which was found for the model equation as, R2 = 0.994. Keywords: Optimization, Oven drying, Drying parameters, Catfish, Response surface methodology