Betaine-based natural deep eutectic solvents (NADESs) for enhanced cryoprotection: Insights into hydrogen bonding behavior and antifreeze mechanisms

The physicochemical properties, hydrogen-bonding networks, and freezing and thawing behaviors of betaine-based NADESs were investigated in this study. Results showed that the NADESs with moderate acidity (pH 6.66–8.10) are suitable for meat and aquatic products and their mild antioxidant activities may reduce the oxidative damage of frozen foods during cryopreservation. Moreover, the hydrogen bond networks in NADESs weaken with higher water content but strengthen at lower temperatures. The NADES possesses a more potent antifreeze property compared to water and sucrose, remaining unfrozen even at −80 °C. Furthermore, the presence of NADESs can mitigate the formation and growth of ice nucleation and suppress the recrystallization process. Additionally, the thawing time can be shortened by 2–4 times with the assistance of NADESs when compared with the water. The simultaneous effects of NADESs during freezing, storage and thawing stages can provides extensive cryoprotection. Applications in frozen shrimp surimi further announced the potentials of NADESs as cryoprotectants for the frozen food industry.