Influence of Ultrasound on Freezing Rate of Immersion-frozen Apples

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 < 0.05), compared to immersion freezing without ultrasound. Results of the effect of ultrasound waves applied on radial or tangential cut samples sonicated for 120 s from −1°C and/or 0°C indicated that at the power level considered there were no significant differences among the ultrasonic radial or tangential irradiated samples of these treatments, though the freezing rates were enhanced and different (P < 0.05) from the control treatment. Some evidence of the influence of ultrasound to induce primary nucleation was also observed.

[1]  J. G. Brennan,et al.  Food engineering operations , 1969 .

[2]  Julian F. V. Vincent,et al.  Anisotropy of apple parenchyma , 1990 .

[3]  R. Volz,et al.  Air volume measurement of 'Braeburn' apple fruit. , 2004, Journal of experimental botany.

[4]  Farid Chemat,et al.  Ultrasound as a preservation technology , 2003 .

[5]  T. Inada,et al.  Ultrasonic-induced nucleation of ice in water containing air bubbles. , 2003, Ultrasonics sonochemistry.

[6]  P. Zeuthen,et al.  Food preservation techniques , 2003 .

[7]  A. Wilhelm,et al.  Power measurement in sonochemistry , 1995 .

[8]  Da-Wen Sun,et al.  Heat and mass transfer models for predicting freezing processes – a review , 2001 .

[9]  N. Galili,et al.  Determining quality of fresh products by ultrasonic excitation : Ultrasonic applications in the food industry , 1994 .

[10]  Zaritzky Noemi.  Physical–Chemical Principles in Freezing , 2011 .

[11]  J. V. García-Pérez,et al.  Ultrasonic drying of foodstuff in a fluidized bed: Parametric study. , 2006, Ultrasonics.

[12]  Da-Wen Sun,et al.  Innovative applications of power ultrasound during food freezing processes—a review , 2006 .

[13]  T. Lucas,et al.  Transport phenomena in immersion‐cooled apples , 1998 .

[14]  P. W. Cains,et al.  Sonocrystallization: The Use of Ultrasound for Improved Industrial Crystallization , 2005 .

[15]  S. Simal,et al.  Ultrasonic Mass Transfer Enhancement in Food Processing , 2003 .

[16]  L. Otero,et al.  Size and location of ice crystals in pork frozen by high-pressure-assisted freezing as compared to classical methods. , 1998, Meat science.

[17]  Da-Wen Sun,et al.  Handbook of Frozen Food Processing and Packaging , 2005 .

[18]  Acoustic enhancement of diffusion in a porous material. , 2003, Ultrasonics.

[19]  Dietrich Knorr,et al.  Applications and potential of ultrasonics in food processing , 2004 .

[20]  Malcolm Povey,et al.  The sonocrystallisation of ice in sucrose solutions: primary and secondary nucleation. , 2003, Ultrasonics.

[21]  Bing Li,et al.  Microstructural change of potato tissues frozen by ultrasound-assisted immersion freezing , 2003 .

[22]  J. Floros,et al.  Acoustically assisted diffusion through membranes and biomaterials , 1994 .

[23]  Bing Li,et al.  Effect of power ultrasound on freezing rate during immersion freezing of potatoes , 2002 .

[24]  D J McClements,et al.  Ultrasonic characterization of foods and drinks: principles, methods, and applications. , 1997, Critical reviews in food science and nutrition.

[25]  Malcolm J. W. Povey,et al.  Ultrasound in Food Processing , 1995 .

[26]  Bajram Zeqiri,et al.  Studies of a novel sensor for assessing the spatial distribution of cavitation activity within ultrasonic cleaning vessels. , 2006, Ultrasonics.

[27]  C. Sterling.  Effect of Low Temperature on Structure and Firmness of Apple Tissue , 1968 .

[28]  L. Otero,et al.  Freezing rate simulation as an aid to reducing crystallization damage in foods. , 1999, Meat science.

[29]  R. Chivers,et al.  A study on the primary and secondary nucleation of ice by power ultrasound. , 2005, Ultrasonics.

[30]  J. Vincent,et al.  COMPRESSIVE STIFFNESS AND FRACTURE PROPERTIES OF APPLE AND POTATO PARENCHYMA , 1993 .

[31]  C. Rosselló,et al.  Influence of ultrasound intensity on mass transfer in apple immersed in a sucrose solution , 2007 .