Optimization of phosphate and salt application to physical and sensory properties of frozen Nile tilapia fillets

Abstract

This study was optimized a critical process, a soaking step, using phosphates with a combination of NaCl and soaking time, with response surface methodology (RSM). A Box-Behnken's design with three-factors, three-levels was used to design the experiment. Physiochemical properties (weight gain, cooking loss, cooking yield, drip loss, moisture, phosphate content) and sensory properties of raw fillets (appearance, texture) and cooked fillets (appearance, odor, taste, texture) were investigated. Three factors of phosphate concentration (X<inf>1</inf>), NaCl concentration (X<inf>2</inf>) and soaking time (X<inf>3</inf>) were optimized. It was found that a significant effect with high R² of models was observed in weight gain, cooking yield, phosphate content and appearance (raw), taste (cooked) and texture (cooked). Those responses were optimized and a goal condition was obtained at 1.4% of phosphate concentration, 2.7% of NaCl concentration, and 115 min of soaking time. This solution gave a high satisfaction, with a high weight gain of 6.52%, cooking yield of 81.12%, low phosphate content of 3876 mg/kg, and high appearance score of 7.5, taste of 6.2, and texture of 6.6, respectively by using 9-point hedonic scaling. It is concluded that phosphates concentration, NaCl concentration, and soaking time are significant factors for the physical and sensory properties of frozen Nile tilapia fillets.