The use of power ultrasound within the food industry is an innovative subject. Application of sound to monitor a process or product is common, e.g. in quality assurance. However, the use of ultrasound to directly improve processes and products is less popular in food manufacturing. In the present work, ultrasound-assisted immersion freezing was investigated on apple samples. Because the apple parenchyma is mechanically anisotropic, the influence of applying ultrasound on radial or tangential orientated samples was also examined. Apple cylinders were immersed in an ultrasonic bath system, which operates at 40 kHz frequency. Experiments were carried out at a power level of 131.3 W (0.23 W/cm2), and ultrasound was applied intermittently for different times from temperatures below and close to the initial freezing point. Results showed that ultrasound application at 0°C or −1°C for 120 s in total, with 30 s intervals, significantly improved the freezing rate represented by the characteristic freezing time up to 8% (P