Changes in the quality of aquatic products during liquid nitrogen quick-freezing: a review

Freezing is a common preservation technique that extends the shelf-life of food by inhibiting microbial and enzymatic activity. Among the various methods, liquid nitrogen quick-freezing (LNQF) stands out for its ultra-rapid freezing rate, which is pivotal for preserving the quality of highly perishable aquatic products. However, a comprehensive framework linking the physical advantages of LNQF to the underlying biochemical mechanisms of quality preservation is lacking. This review systematically bridges this gap by comparing the operational principles, advantages, and limitations of predominant LNQF methods, including immersion freezing, cold gas cycle freezing, and spray freezing. This study then meticulously details the quantitatively demonstrated benefits of LNQF on the quality parameters of various aquatic products. A key distinct contribution of this review is the proposal of ferroptosis, an iron dependent, lipid peroxidation-driven cell death pathway, as a novel and plausible mechanistic hypothesis to explain the quality degradation inhibited by LNQF. Furthermore, this review explores the synergistic potential of combining LNQF with pretreatment. Finally, we provide a critical outlook on intelligent process control and sustainable development within the field. This work not only synthesizes current knowledge but also provides a new theoretical lens (ferroptosis) and a practical framework (hybrid techniques) to guide future research and innovation in the high-quality frozen aquatic product industry.