The science of delicious food

Food texture has a crucial influence on the enjoyment of eating and acceptance of new food. It can make the difference between passing on a plate and love at first bite.

To date, most studies on food texture centre on relating a food’s overall composition to its mechanical properties. However, an understanding of how microscopic structure and changes in the shape of food affect food texture remains underdeveloped.

Researchers from Denmark and Germany conducted a series of experiments relating to food microstructure and rheology. The study published in Physics of Fluids by AIP Publishing looked at two dishes — foie gras and pâté — and showed how soft solids and some liquids deform to create texture. They used coherent anti-Stokes Raman scattering (CARS) microscopy to relate the molecular makeup of the fat in foods with the rheological and mechanical properties of the food.

“Using soft matter physics tools and models, we connected structural information in the food across length scales,” said author Thomas Vilgis. “We joined microscopy and rheology to understand the mouthfeel of food from a gastrophysical standpoint.”

Both deriving from duck livers, the two dishes are similar enough in overall structure, and their differing fat distribution provided a window into how fat affects texture.

“There are further different interesting aspects that can be targeted to create new products with the same features as these products,” said author Mathias P Clausen.

The researchers wanted to determine if they could create foie gras-like textures using other ingredients, such as non-animal based, and also whether or not they could create melting and creamy texture from different fat sources.

They used CARS microscopy to vibrate chemical bonds in foods to tunable frequencies and cause them to emit light. The technique has been used for decades in other fields but, so far, has received relatively little use in food science.

The fat in foie gras had arranged into an irregularly shaped, weakly linked fat network embedded in a protein matrix, which made its mouthfeel harder, more brittle and more elastic than pâté’s.

Microscopic structure of fat (red) explains texture differences between foie gras (left) and pâté (right). Image credit: Matias A Via and Mathias P Clausen.

The greater number of rounder and smoother fat particles and lack of an interconnected network were responsible for the pâté’s softer texture.

Clausen hopes their research stokes further interest in investigating which microscopic features of foods can be tweaked. The group looks to study other components of foods with advanced microscopy, such as protein arrangement, and see if they can use their findings to create foods that mimic the texture of foie gras.

Top image credit: ©stock.adobe.com/au/yuliiaholovchenko