Ultrasound and salt reduction effect on physicochemical and rheological properties of meat emulsions

Power ultrasound and salt reduction effects on meat emulsions' physicochemical and rheological properties were determined. Therefore, meat emulsions with different NaCl concentrations (1, 1.5, 2, and 2.5%) were treated in an ultrasonic bath (40 kHz, 200 W, & 9.34 W/cm² ) at different times (0, 15, and 45 min). Results showed that salt reduction and ultrasound time significantly (p < 0.05) affected the cooking loss, water holding capacity, water activity, pH, color, hardness, viscosity, storage modulus (G'), loss modulus (G″), and phase angle δ. Meat emulsions with low salt content (1 and 1.5% NaCl) showed significantly higher values of cooking loss than standard emulsions (2.5% NaCl), while ultrasound duration of 15 min reduced the cooking loss (12 to 27%). Hardness, color, pH, and water activity (aw) decreased with salt reduction. Ultrasounds increased the hardness, viscosity, G', and G'' values in reduced-salt meat. The experimental data of apparent viscosity were properly fitted to the mathematical model of Ostwald-de-Waele. Ultrasound increased consistency (k) and decreased flow behavior index (n) in emulsions with 1.5 to 2.5% NaCl. Ultrasound at 15 min induced gelation in emulsions with 1.5 and 2.0% NaCl (40 and 20% NaCl reduction). The formulation with 2.0% NaCl was found to be the maximum concentration that did not sacrifice meat emulsion quality. When combined with 15 min of ultrasound, this formulation yielded results comparable to the standard formulation. PRACTICAL APPLICATION: Results contribute to developing reduced-salt meat emulsions using power ultrasounds. Therefore, using ultrasounds allows for a 20% reduction in salt content while maintaining the quality of the meat emulsion.