Optimisation of infrared radiation-assisted heat pump drying for Pangasius krempfi

Abstract

Pangasius krempfi is a high-value aquatic species; however, traditional drying methods such as sun drying and conventional kiln drying present several limitations, including extended drying time, inconsistent product quality, and limited process control. This study aimed to optimise the drying process of P. krempfi using a hybrid drying technology combining a heat pump and infrared radiation. The experimental design followed response surface methodology (RSM) with four independent variables: drying temperature (40-60°C), air velocity (1-3 m/s), material thickness (1-2 cm), and sorbitol concentration (5-25%). Evaluation criteria included drying time, rehydration rate, sensory score, and water activity. Experimental data were analysed using second-order regression and analysis of variance (ANOVA). The results indicate that drying temperature and sorbitol concentration had a significant impact on product quality parameters (p<0.01). The optimal conditions were determined as a drying temperature of 60°C, an air velocity of 1.4 m/s, a sample thickness of 1.0 cm, and a sorbitol concentration of 5%, yielding a drying time of 5.2 h, a rehydration rate of 63%, a sensory score of 18.34/20, and a water activity of 0.57. These findings contribute to strengthening the scientific basis for the adoption of combined drying technologies in the processing of P. krempfi and similar aquatic products.