Science of better tasting food

Food Rheology is the science which focuses on understanding the consistency of foodstuff -how it flows in a liquid state- that helps to understand how long food can be stored or remain stable and the texture of the resulting product.

In a study published this week in the journal Physics of Fluids, from AIP Publishing, Taiki Yoshida, Yuji Tasaka and Peter Fischer have developed a better method that builds on a century-old method to test the texture of food.

Improving the texture of food, which includes properties that determine how people experience biting and swallowing, has been an important part of the development of more enjoyable foods.

Traditional methods have been unable to produce information about time-dependent properties. Recently traditional rheological testing methods coupled with inner visualization techniques and ultrasonic imaging have been seen to produce better results.

However, in order to completely understand the properties which can lead to better tasting food, better methods for testing are required to capture the motion inside liquid materials, especially in the case of foods that are complex liquids, like gelled desserts.

To present the updated testing method, researches used a popular Japanese dessert called Fruiche, which includes fruit pulp and whole milk that transforms into a gelled form with an egg carton-shaped structure.

The new method, the ultrasonic spinning rheometry method, developed can measure linear viscoelasticity and phase lag simultaneously in an opaque liquid, and thereby capture information about complex rheological properties.

"Evaluation of food rheology with time dependence is challenging target," researcher Yoshida said.

"Based on the equation of motion, the ultrasonic spinning rheometry method can evaluate instantaneous rheological properties from the measured velocity profiles, so it can present true rheological properties and their time dependence from the perspective of physics of fluids" the researcher said.

The updated method has applications in chemical engineering for understanding polymerisation and dispersion densities, as well as in complex fluids such as clay, with applications in civil engineering and cosmetics.

The researchers plan to further advance the method to include more points at which information can be gathered about the invisible properties of complex liquids.

They also plan to further develop the industrial aspects of the technique, including in-line rheometry for test samples flowing in a pipe.