Impact of In-Situ CO_2 Nano-Bubbles Generation on Freezing Parameters of Selected Liquid Foods

摘要

The impact of in-situ CO2 nano-bubbles generation on the freezing properties of soft serve, milk, and apple juice was investigated. Carbonated (0, 1000, and 2000 ppm) liquid foods contained in a tube were submerged and cooled for 90 min in a pre-set ethylene glycol bath (-15 degrees C). Before the enclosed liquid reached 0 degrees C, the vibration was discharged through ultrasound in the bath to create nano-bubbles within the carbonated food samples, and the changes in temperature for 90 min of each food were recorded as a freezing curve. The time for onset of nucleation of control soft serve mix was halved in samples with 2000-ppm CO2 due to the presence of nano-bubbles. Likewise, the nucleation time for milk with and without nano-bubbles at the same CO2 concentration of 2000 ppm was 7.9 +/- 0.1 and 2.8 +/- 0.8 min(,) respectively. The generation of CO2 nano-bubbles from 2000-ppm CO2 level in 10 (o)Bx apple juice displayed -9.3 +/- 0.3 degrees C nucleation temperature while the control one had -11.7 +/- 0.9 degrees C.