Ice recrystallization inhibition behavior by wheat flour and its synergy effect with antifreeze protein III

Ice recrystallization (IR) is an undesirable phenomenon in which the size of an ice crystal grows in the frozen medium. Based on the Ostwald ripening theory, the IR kinetics of wheat flour system were investigated under isothermal conditions (−10 °C). The results showed that 30% (w/w) sucrose solution had an IR rate of 3.34 ± 0.29 μm3/min, however adding 5% (w/w) wheat flour reduced the rate to 0.56 ± 0.15 μm3/min. To understand the inhibitory effect of wheat flour, the size distribution was analyzed. The results indicated that wheat flour reduced both the size and size distribution of the ice crystals in the sucrose solution, suggesting that narrowing the size distribution is the candidate mechanism for IR inhibition. Further, combining antifreeze protein III with the wheat flour system decreased IR rate in a synergistic manner. In presence of wheat flour, only 0.1 μg/mL of AFP III was sufficient to lower IR rate significantly, while without it, 0.5 μg/mL of AFP III was required.