MONITORING THE DAMPING CHARACTERISTICS OF LIQUID FOODS IN CYLINDRICAL CONTAINERS

The oscillatory damping characteristics of model food solutions and gels in cans were studied in an apparatus designed for nondestructive testing. Oscillations, resulting from a small angular displacement, were monitored by an accelerometer and recorded by a fast recorder. An empirical damping coefficient, derived from an exponential decay constant was found to be sufficiently sensitive to monitor the apparent viscosity of liquid contents. In the case of gelation, the magnitude of the damping coefficient considerably increased when a very soft gel was formed. When the gel gained rigidity, however, there was a dramatic drop in the coefficient value to levels well below those of the nongelled contents. At this stage, however, there was also an appreciable drop in the system's natural frequency which could easily be recorded. This provided a complementary criterion that enabled unambiguous distinction between “viscous” and gelled contents.