Physics models better define what makes pasta al dente
Mathematical model describes swelling, elasticity, adhesion of noodles as
they cook

Date:
April 13, 2022
Source:
American Institute of Physics
Summary:
Researchers examined how pasta swells, softens, and becomes
sticky as it takes up water. They combined measurements of pasta
parameters, such as expansion, bending rigidity, and water content
to solve a variety of equations to form a theoretical model for
the swelling dynamics of starch materials. The team observed how
the noodles come together when lifted from a plate by a fork. This
provided them with a grounding of how water- driven hygroscopic
swelling affects pasta's texture.



FULL STORY ========================================================================== Achieving the perfect al dente texture for a pasta noodle can be
tough. Noodles can take different times to fully cook, and different
recipes call for different amounts of salt to be added. To boot, sometimes noodles will stick to each other or the saucepan.


==========================================================================
In Physics of Fluids, by AIP Publishing, researchers from the United
States examined how pasta swells, softens, and becomes sticky as it
takes up water.

They combined measurements of pasta parameters, such as expansion,
bending rigidity, and water content to solve a variety of equations to
form a theoretical model for the swelling dynamics of starch materials.

Author Sameh Tawfick, from the University of Illinois at Urbana-Champaign,
said exploring the properties of noodles was a straightforward pivot
from the lab's main work of studying the fluid structure interaction of
very flexible and deformable fibers, hairs, and elastic structures.

"Over the last few years, we joked about how pasta noodle adhesion is
very related to our work," he said. "We then realized that specifically,
the mechanical texture of noodles changes as function of cooking, and
our analysis can demonstrate a relation between adhesion, mechanical
texture, and doneness." When the pandemic hit, the idea gained traction,
and students and postdocs started working on it at home and in the lab.

The team observed how the noodles come together when lifted from a
plate by a fork. This provided them with a grounding of how water-driven hygroscopic swelling affects pasta's texture.

As pasta cooked, the relative rate of the noodle's increase in girth
exceeded the rate of lengthening by a ratio of 3.5 to 1 until it
reached the firm texture of al dente, before becoming uniformly soft
and overcooked.

As pasta is pulled from liquid, the liquid surface energy creates a
meniscus that sticks noodles to one another, balancing the elastic
resistance from bending the noodles and aided by adhesion energy from
the surface tension of the liquid.

The degree to which a noodle was cooked was directly related to the
length of the portion that adhered to its neighbors.

"What surprised us the most is that the addition of salt to the boiling
water completely changes the cooking time," Tawfick said. "So, depending
on how much salt is added to the boiling water, the time to reach al
dente can be very different." Tawfick hopes the group's work inspires
others to find simple methods for studying soft materials and looks to investigate the role of salt in swelling.


========================================================================== Story Source: Materials provided by American_Institute_of_Physics. Note: Content may be edited for style and length.


========================================================================== Related Multimedia:
* Pasta_noodles_hanging_vertically_after_cooling ========================================================================== Journal Reference:
1. Jonghyun Hwang, Jonghyun Ha, Ryan Siu, Yun Seong Kim, Sameh Tawfick.

Swelling, softening, and elastocapillary adhesion of cooked pasta.

Physics of Fluids, 2022; 34 (4): 042105 DOI: 10.1063/5.0083696 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220413104141.htm

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