Monitoring of single eye growth under known gas pressure: Magnetic resonance imaging measurements and insights into the mechanical behaviour of a semi-hard cheese

• A dedicated setup was developed to measure simultaneously pressure and volume in a cheese eye.
• Low pressure (< 3.5 kPa) was found to be able to inflate an eye in semi-hard cheese.
• Eye growth in semi-hard cheese occurred in the linear domain.
• No time-independent elasticity was found to control eye growth.
• Linear viscoelasticity fits well with the eye growth in semi-hard cheese.

A dedicated setup was developed for simultaneous measurement of pressure and volume in a single eye of semi-hard cheese. A known level of gas pressure was applied to the cheese eye and the resulting eye inflation was monitored using Magnetic Resonance Imaging (MRI). Image analysis methods were developed to measure the eye volume, horizontal and vertical diameters of the eye and the deflected shape of the top surface of the cylinder of cheese under study. Two amounts of pressure were applied to attempt to reproduce a creep-recovery experiment in situ. In the last stage, lowering of pressure was applied in order to investigate time-independent elasticity. The core of the semi-hard cheese was found to show no relevant time-independent elasticity during processing in a 90 h experiment. A low amount of pressure (< 3.5 kPa) was able to inflate already existing eyes in semi-hard cheese within the linear domain.