Ting Duan, Xuzhong Yang, Lihong An, Shuzhen Ma, Xin Liang, Xuerong Shi, Meizhao Chen, Xu Liu, Fei Li, Shaotong He, Jijun Gong, Mingqiang Ye
This study aimed to evaluate the impact of −20 °C static air freezing (−20 °C-SAF), −35 °C blast air freezing (−35 °C-BAF), −30 °C immersion freezing (−30 °C-IF), and −80 °C liquid nitrogen freezing (−80 °C-LNF) on quality of tilapia fillets during 90-day storage period at −18 °C. Utilizing response surface methodology, an optimal formulation for composite coolants was established, comprising 20.00% ethanol, 10.19% propylene glycol, 8.00% NaCl, and 15.00% betaine. Key findings indicated that both −30 °C-IF and −80 °C-LNF methods significantly enhanced freezing rates, generated smaller and more uniformly distributed ice crystals, compared with −20 °C-SAF and -35 °C-BAF ( p < 0.05). During storage at −18 °C, both the −30 °C-IF and −80 °C-LNF treatments improved quality maintenance in comparison to conventional methods ( p < 0.05). Notably, the preservation outcomes achieved with −30 °C-IF were comparable to those obtained with −80 °C-LNF across most assessed quality indices ( p > 0.05), while simultaneously reducing the consumptionof freezing media. These finding position −30 °C-IF as a potentially cost-efficient alternative to premium quick-frozen tilapia products. • An optimal liquid coolant formulation was successfully developed for the immersion freezing of tilapia fillets. • The −30 °C-IF achieved the highest efficiency, marked by the shortest transit time through the zone of maximum ice crystal formation (Z-MICF), followed by −80 °C-LNF. • Both −30 °C-IF and −80 °C-LNF significantly outperformed −20 °C-SAF and −35 °C-BAF, with minimal quality differences observed between the two former methods. • The −30 °C-IF treatment produced the most refined ice crystal morphology, which effectively preserved the integrity of the muscle fibers. • Compared to −80 °C-LNF, the −30 °C-IF method presents a significant advantage in terms of potential cost efficiency.