Phase Transition Analyzer

The Phase Transition Analyzer™ was developed in the Wenger Technical Center to measure the "controlling" glass (Tg) and melt (Tm) transitions of a complex mixture of biopolymers that often comprise an extruded food or feed product.

The "controlling" Tg and Tm is the temperature at which sufficient amount of sample is softened to allow for particle compaction (Tg) or melted to allow for flow (Tm) through an orifice.

Key Features

• Temperature range: 5 - 200°C
• Heating and cooling rates up to 25°C/min
• Pressure measurement and control up to 210 bar
• Software package to measure and record temperature, pressure and sample movement
• Real-time graphical display of data during testing
• Data analysis software to determine Tg and Tm

The Wenger Phase Transition Analyzer is a closed-chamber capillary rheometer, which uses a combination of pressure, temperature, time and moisture to measure the Tg and Tm of a biopolymer. It consists of two sealed chambers, separated by an interchangeable capillary die, that prevents sample moisture loss so testing can be at temperatures far exceeding 100°C. The sample chamber is of fixed volume, and a constant pressure is maintained on the sample throughout the test. The sample movement, which is tracked and recorded during testing, is used to determine the sample’s controlling Tg and Tm.

The Wenger Phase Transition Analyzer provides knowledge about the Tg and Tm of a biopolymer that can be directly applied to the extrusion cooking process. When a sample’s Tg and Tm is combined with a mass and energy audit of an extrusion system, it enables an extrusion technologist to accurately map the process – a valuable aid to troubleshooting and better characterization of the extrusion operation. The Phase Transition Analyzer data also has been correlated to important properties of both raw materials and extruded products.