Ice crystal size.
The freezing rate, and subsequently, ice crystal size determine the
quality of frozen food. It is critical that we obtain quantitative
information from frozen food about the size and distribution of ice
crystals in a nondestructive manner. Research has been conducted on
harnessing the ultrasonic properties of food to develop a non-invasive,
rapid technique that measures the ice crystal size distribution of
frozen food. Work has involved measuring ultrasonic transmission through
a frozen food system. The results show that changes in ultrasonic
velocity are highly correlated with temperature variation in the
product. The ultrasonic velocity of ice is about twice that of water.
Ultrasonic velocity profiles could provide significant data about
freezing history comparable to temperature profiles. They could be used
to monitor the phase change of water within frozen foods. Contact: Kumar
Mallikarjunan, Department of Biological Systems Engineering, Virginia
Polytechnic Institute and State University, 312 Seitz Hall, Mail Code
0303, Blacksburg, VA 24061. Phone: 540-231-7937. Fax: 540-231-3199.