Quality Maintenance of Litopenaeus vannamei during Frozen Storage Using Choline Chloride-Sorbitol Natural Deep Eutectic Solvents

To explore the antifreeze and water-retaining effects of natural deep eutectic solvents (NADES) as green antifreezes on frozen Litopenaeus vannamei, shrimps were soaked in NADES prepared with mixtures of choline chloride (ChCl) and sorbitol at different molar ratios before frozen storage. The effect of NADES on the quality of frozen shrimps was evaluated by measuring changes in thawing loss rate, pH, and thiobarbituric acid reactive substances (TBARS) value during a 60-day storage period. Compared with the distilled water and sorbitol groups, NADES (ChS25) with a ChCl/sorbitol ratio of 2:5 demonstrated excellent antifreeze effects, significantly reducing the thawing loss rate, delaying the decline in water-holding capacity, and minimizing damage caused by ice crystal formation during frozen storage. Analyses of pH, total volatile basic nitrogen (TVB-N) content, and TBARS value indicated that ChS25 effectively inhibited protein and amino acid decomposition as well as lipid peroxidation, slowing down the decline in freshness. Moreover, ChS25 alleviated the deterioration of sensory properties (color, springiness, hardness, and chewiness) of shrimp during storage, effectively maintaining the quality of frozen shrimp. In conclusion, this study provides a theoretical basis for applying green, low-calorie NADES antifreezes in aquatic product preservation.