The structure of food, including characteristics that determine how consumers feel about biting and swallowing, is an important part of the development of more fun foods. To fully understand these properties, better testing methods and devices are needed to capture the movement into liquid materials, especially in the case of foods that are complex liquids, such as gelled desserts.
Test devices have been improved using different geometries in the test chamber, and more recently, better results have been obtained using information from rheological tests in combination with results from other tests, such as internal visualization techniques and ultrasound imaging. But traditional methods have not been able to produce information on time-dependent properties.
In a study published this week Physics of Fluids Taiki Yoshida, Yuji Tasaka, and Peter Fischer introduce an updated method that can measure linear viscoelasticity and phase delay simultaneously in an opaque liquid. The ultrasound spinning rheometry method they developed replaces the velocity profiles of foods in the motion equation to capture information on complex rheological properties.
The researchers used a popular Japanese dessert called Fruiche, which includes fruit pulp and whole milk that transforms into a jelly shape with an egg-carton-shaped structure. The complexity of this fluid includes properties that are difficult to measure with traditional rheometry methods due to the effect of shear history, shear bands, shear location, wall sliding and elastic instability.
"Evaluating food theology with time dependence is challenging goal," said Yoshida. "Based on the equation of motion, the ultrasound spinning rheometry method can evaluate immediate rheological properties from the measured velocity profiles so that it can present real rheological properties and their time dependence from the physics perspective for fluids."
The updated method has applications in chemical engineering to understand polymerization and density, as well as in complex liquids such as clay, with applications in plant technology and cosmetics. The researchers plan to further develop the method to include more points where information can be gathered about the invisible properties of complex fluids. They also plan to further develop the industrial aspects of the technology, including in-line rheometry for test samples flowing in a tube.
Movement and flow: Simulate the complexity of liquids and threads in the virtual world
Taiki Yoshida et al., Ultrasound Spin Rheumatoid Test on the Rheology of Gelled Food to Make Desserts with Better Taste, Physics of Fluids (2019). DOI: 10.1063 / 1.5122874
Century old food testing method updated to include complex fluid dynamics (2019, November 8)
retrieved November 9, 2019
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