Ultrasound-assisted thawing accelerates the thawing of common carp (Cyprinus carpio) and improves its muscle quality

The effects of different power (0, 100, 300, and 500 W) ultrasonic-assisted immersion thawing (UT) on the thawing time and muscle quality (thawing/cooking loss, shear force, colour, water distribution and microstructure) of common carp (Cyprinus carpio) were investigated. The results showed that the thawing time decreased gradually with the increase of ultrasonic power, and the thawing time of ultrasonic thawing at 500 W (UT-500) was the shortest among all the thawing methods (P < 0.05). However, the thawing and cooking losses of UT-500 samples were the largest among all thawed samples, while those of UT-300 samples were the smallest (P < 0.05). In addition, the result of fish colour indicated that UT-300 was beneficial for maintaining the colour of fish muscle after thawing. Low field nuclear magnetic resonance analysis showed that UT-300 effectively reduced the fluidity and loss of immobilised and free water. Microstructure analysis showed that the microstructure of UT-300 sample was more complete than that of other thawing treatment samples. Therefore, appropriate ultrasonic power (300 W) during thawing could accelerate the thawing process of frozen common carp, and maintain its muscle quality.