Ultrasound measurements to monitor the specific gravity of food batters

This paper describes the design and application of a low cost ultrasound system to monitor the specific gravity of batter as it is mixed. The quantity of air is believed to be the main factor in determining the quality of the finished product and specific gravity measurement is common for assessing the quality and progress of the mixing process. A probe is designed to allow measurements in reflection and the relationship of ultrasound gain to specific gravity determined theoretically and justified experimentally. Operation was conducted in pulsed mode using a nominally 2.25 MHz, 15 mm diameter transducer. The work may have application to measurements on industrial sludges in which similar material properties are observed.