Method for improving, by using power-variable ultrasonic waves, frozen fish fillets treated by means of salt-water immersion process

A method for improving, by using power-variable ultrasonic waves, frozen fish fillets treated by means of a salt-water immersion process comprises the following steps:

• (1) pretreating raw fish to obtain fish fillets;
• (2) precooling the fish fillets;
• (3) stacking the precooled fish fillets to obtain a fish fillet stack;
• (4) freezing the fish fillet stack by using a salt-water immersion process, and performing power-variable ultrasonic wave treatment, which is specifically as follows:
• immersing the fish fillet stack in a sodium chloride solution at −18° C. to −20° C., and performing power-variable ultrasonic wave treatment;
• the concentration of the sodium chloride solution is 25 to 30% (m/m);
• the power-variable ultrasonic wave treatment specifically comprises:
• under an ultrasonic wave frequency condition of 20 kHz, firstly treating for 5 to 10 min under the power of 800 to 600 W, and then changing the power to 200 to 600 W for treating for 5 to 15 min;
• and
• (5) feeding the fish fillets into freezing storage.