Non-destructive Evaluation of Voids in Kamaboko by an Ultrasonic Pulse Echo Technique

Abstract

Kamaboko containing a lot of voids which arise from the air bubbles taken in the grinding process of fish meat during manufacturing is complained about its poor quality. An ultrasonic pulse echo technique was applied to evaluate the size and number of these voids in kamaboko by using a standard ultrasonic inspection apparatus (a single-type). The frequency used was 2.25MHz. The number of voids larger than 1mm diameter in kamaboko was determined by counting the number of ultrasonic echo pulses on the oscillograms. The number of echo pulses gradually increased as the increase of the number of voids while the voids' number was small. However, an abrupt saturation of detecting echo pulse took place. This may be caused by a rapid growth of the shaded space generated by void particles which reflected ultrasonic pulse wave. This phenomena was simulated by a simplified model calculation, which suggested a way of avoiding saturation. The non-destructive detection of voids in kamaboko using ultrasonic technique is concluded to feasible.