Trehalose and sodium pyrophosphate inhibit ice-induced freezing quality deterioration of surimi: A comparative study on water migration, ice crystal growth, glass transition and state diagram

This study investigated the effects of trehalose (TH) and sodium pyrophosphate (SPP) on surimi freezing quality in terms of water migration, ice crystal growth, glass transition and state diagram. Both trehalose and sodium pyrophosphate could alter water distribution and restrict water fluidity. Trehalose outperformed sodium pyrophosphate in inhibiting ice crystal growth and lowering freezing temperature. State diagram demonstrated that the highest glass transition temperature (Tg’) was for TH/surimi (−30.17 °C), followed by SC/surimi (−38.88 °C), SPP/surimi (−43.84 °C), and pure surimi (−53.87 °C). Trehalose increased Tg’, shortened “temperature region for maximum ice formation” (−17.39∼ −53.87 °C to −19.58∼ −30.17 °C) and reduced un-freezable water content (26.55% to 20.70%) owing to reduced plasticization of water and increased effective molecular weight. Overall, trehalose could better improve surimi freezing quality by aforementioned low-temperature protection effects. This study elucidates anti-freezing mechanisms of trehalose and sodium pyrophosphate for surimi, providing a reference for their application in surimi frozen storage.