The effect of magnetic field on the quality of channel catfish under two different freezing temperatures

The effect of magnetic field on quality changes of frozen channel catfish under two different freezing temperatures was investigated in this paper. During the freezing process of channel catfish under -18 °C and -40 °C, which represented slow freezing and fast freezing conditions, static magnetic field (SMF) intensities of 0, 1.7, 3.5, 7.0 and 10.7 mT were applied. The temperature was monitored during the freezing process, and parameters of weight loss, pH, and textural properties were measured and compared. The results show that for the freezing condition of -40 °C, the time spent at the maximum ice crystals formation stage was significantly reduced after the application of SMF. The total weight loss of SMF samples frozen at both freezing temperatures had a significant reduction. The pH was closer to the fresh samples after 7.0 - 10.7 mT and 10.7 mT SMF intensities were applied to -18 °C and -40 °C, respectively. SMF had a beneficial effect on improving the hardness and chewiness properties of frozen fish, while it was only obvious at -18 °C freezing condition.