Effects of micro-nano bubbles on the nucleation and crystal growth of sucrose and maltodextrin solutions during ultrasound-assisted freezing process

The effects of micro-nano bubbles (MNBs) on the ultrasound-assisted freezing process of sucrose and maltodextrin solutions were investigated and different freezing characteristics of both nucleation period and crystal growth period were analyzed. Results showed that the introduction of MNBs was effective for the acceleration of freezing process, including the ice nucleation and crystal growth of both sucrose and maltodextrin solutions. Under optimal combination conditions, both sucrose and maltodextrin solutions with MNBs achieved a remarkable reduction in the supercooling degree and freezing time (Tn = −1.24 ± 0.09 °C, tp = 92 ± 3.88 s and t = 230 ± 4.82 s for sucrose solution, and Tn = −1.97 ± 0.13 °C, tp = 102.9 ± 8.62 s and t = 240.2 ± 3.72 s for maltodextrin solution) as compared with conventional immersion freezing (Tn = −7.87 ± 4.65 °C, tp = 126 ± 17.86 s and t = 303 ± 28.12 s for sucrose solution without MNBs, and Tn = −8.24 ± 4.73 °C, tp = 127 ± 18.12 s, t = 303.83 ± 17.86 s for maltodextrin solution without MNBs). This study suggested that the introduction of MNBs was a feasible method for enhancing ultrasound-assisted freezing process.