• DC-EF modulated ice nucleation and crystal growth in an intensity-dependent manner • Moderate fields (5 kV) optimally balanced freezing rate enhancement and protein stability • DC-EF significantly inhibited myofibrillar oxidation and preserved moisture distribution • Findings support DC-EF as a scalable physical strategy for improving frozen aquatic products This study explored the effects of direct current electric fields (DC-EF, 1-11 kV) on the freezing behavior and quality attributes of tilapia. Our results showed that compared with the DC-EF-free group, DC-EF treatments at 1-7 kV significantly accelerated the freezing process, while higher intensities (9-11 kV) exhibited a diminished effect. Specifically, the 3 kV treatment produced the shortest total freezing time, enhancing the freezing rate by 15.7%, while the 5 kV treatment achieved the shortest phase transition period, shortening it by 36.2%. Notably, an additional significant effect was observed at 5 kV, manifested by a reduction in ice crystal size and tissue void formation, concurrent with a marked inhibition of myofibrillar protein oxidation and water migration. Meanwhile, the 7 kV treatment most effectively preserved protein secondary structures, preventing the α-helix to random coil transition. These results demonstrated that the effect of DC-EF on frozen tilapia was intensity-dependent, with moderate fields (5 kV) exhibiting the most beneficial overall effects. This study validated the potential of DC-EF as a viable physical method for enhancing freezing efficiency and maintaining product stability, thereby paving the way for its theoretical understanding and industrial utilization in frozen aquatic product processing.
Chen et al. (Sun,) studied this question.