Use of Ultrasonic sound is very common as a diagnostic tool in the medical industry but its application in other areas was restricted somewhat till recently. In biological research sonicator that generates the ultrasonic sound waves is used to disrupt the cell wall in microorganisms to extract enzymes and study their characteristics. Lately food industry is finding use of this technology for cutting cheese, accelerating some reactions, improving juice extraction from fruits and cleaning processing equipment. There are also other reported use of Ultrasonic sound in food industry though it is not wide spread. Recently a totally new application of Ultrasonic energy has been reported in bakery industry in the manufacture of sponge cakes.
"The authors note that as breads, sponges and biscuit owe their distinctive appeal to their aerated structure, the goal of their study was to investigate the potential use of power ultrasonic in improving this essential attribute. As the formation of air cells during mixing is known to be important to a cake's texture, the effect of application of ultrasonic waves during the batter mixing stage was studied in terms of batter and sponge cake quality, said the Malaysian team. In terms of previous food processing applications, power ultrasound has been used to reduce total fermentation time of yoghurt after inoculation, to shorten the ice cream freezing process time and to reduce the drying time of orange peel, said the researchers. They note that the technique has also been used to minimize flavour loss, induce greater homogeneity and to generate significant energy savings during heat pasteurization of sweet juices".
Ultrasonic waves work through the phenomenon of cavitation which creates high temperature and pressure in a liquid medium, bringing about changes in the viscosity characteristics of the system. Though the cake batter is not considered a liquid system, still its behavior as a soft medium enables the Ultrasonic waves to improve the ultimate quality of the sponge cake on baking. Though the above study was limited in scope as it was carried out under laboratory conditions, it has the potential to become the standard for the bakery industry in many applications.V.H.POTTY