Development of reduced-salt gel of silver carp meat batter using low frequency ultrasound: Effect on color, texture, cooking loss and microstructure

Purpose: To develop reduced-salt silver carp meat gels using low frequency ultrasound. Methods: Silver carp meat batters were prepared with 0.5, 1 (reduced-salt) and 2 % (regular salt), and sonicated (20 KHz, 500 W) for 30 and 40 min, or unsonicated (control). Changes in gel properties were evaluated in terms of color, texture, cooking loss and microstructure using color measurement, puncture test, cooking loss and scanning electron microscopic (SEM) analysis, respectively. Results: Ultrasound and salt exposure led to marked effects on color, texture and cooking loss in fish meat gels (p < 0.05). Reduction in salt content increased the lightness (L*) and cooking loss; and also decreased the sample values of greenness (-a*), breaking force, rupture distance and gel strength. Scanning electron microscopy (SEM) on regular-salt level samples showed that ultrasonic exposure decreased dense aggregates and increased the number and distribution of small cavity samples. Reduced-salt samples (1 % salt) subjected to 30 min sonication had better color (lighter) than control (0 min sonication), better texture (higher gel strength) and cooking loss comparable to that of regular-salt level sample subjected to 30 min sonication, and similar to microstructures from normal salt samples without ultrasound exposure. Conclusion: Low frequency ultrasound is suitable for preparing reduced-salt fish meat gels under suitable ultrasonic conditions.