Stable launches rig for pectin and gelatine users

UK provider of texture analysis equipment Stable Micro Systems this week announced the launch of an annular pumping rig for measuring the relative proportions of viscous behaviour and elastic behaviour in visco-elastic materials.

Of particular pertinence for food manufacturers using ingredients such as gelatine and pectin, the new rig allows existing users of TA.XT2i and TA.XTPlus texture analysers to perform a well-established test, without a traditional rotational rheometer.

Visco-elastic materials exhibit both elastic (spring-like) and viscous (liquid-like) behaviours when subjected to stress or strain. Stable Micro Systems' new rig studies the melting, setting and curing phenomena of these materials, such as gels and non-self-supporting materials. It works by measuring changes in force as a ribbed cylindrical probe follows a sinusoidally oscillating path through the sample held in a vessel.

According to Stable Micro Systems​ the "frequency" (speed) of the oscillations plays an essential role in the test. Lower frequencies tend to favour viscous behaviour, as the sample is given time to flow past the probe, whereas high frequencies cause samples to behave more like solids. Similarly, temperature needs to be controlled and accurately measured, as it has a significant impact on the material's internal structure and mechanical properties.

The temperature of the annular pumping rig can be controlled by circulating water through the walls of the sample vessel. Unlike traditional rheometers, the company claims that the temperature can be measured both on the outer surface of the ribbed probe and on the inner surface of the vessel, giving important information on the temperature gradient within the gap.