Designing the perfect piece of chocolate

Date:
April 21, 2022
Source:
Universiteit van Amsterdam
Summary:
We like some foods, and dislike others. Of course, the way food
tastes is important, but mouthfeel, and even the sound that food
makes when we bite it, also determine whether we enjoy the eating
experience. Is it possible to design edible materials that optimize
this enjoyment? Physicists and food researchers show that indeed
it is.



FULL STORY ==========================================================================
We like some foods, and dislike others. Of course, the way food tastes is important, but mouthfeel, and even the sound that food makes when we bite
it, also determine whether we enjoy the eating experience. Is it possible
to design edible materials that optimize this enjoyment? Physicists and
food researchers show that indeed it is.


==========================================================================
In research that was published in Soft Matterthis week, researchers
from the University of Amsterdam, Delft University, and Unilever,
demonstrate that the mouthfeel of an edible substance can be designed,
just like properties of many other materials can. That is: they create metamaterials, materials that are not found in nature but that are
carefully constructed in the lab. Their building material of choice is
not wood, concrete or glass -- they build their materials from chocolate.

Designing mouthfeel As both professional and amateur bakers know very
well, chocolate is not an easy material to work with. Simply heating it
up and cooling it down can turn soft chocolate into much more brittle
tempered chocolate, or vice versa.

Therefore, the first challenge for the researchers was to get their
building material under control. They did this by very carefully heating
it up, adding some cold chocolate, cooling it down again... and then
putting it in a 3D printer. This allowed them to print essentially any
shape of chocolate material they wanted, while guaranteeing that the
base material always had the same properties.

The first shape of edible material that the scientists experimented with
was an S-shaped chocolate with many twists. The goal was to test how this material would break and how that breaking would be experienced in the
mouth. Not surprisingly, the breaking properties depended strongly on
the direction of 'biting'. When the chocolate was pressed from above,
many different cracks occurred one after another, but when pressed in
the direction perpendicular to the picture, usually only a single crack occurred. This was tested mechanically, as in the picture linked to below,
but also by feeding the chocolates to a panel of 10 -- very willing --
test persons. Both the mechanical tests and the test panel confirmed
moreover that the ease of bite was better in the direction shown in link
to the picture below.

The more cracks, the better Most people enjoy the experience of food
crackling down in their mouths -- the more cracks, the better. Having
shown that such an experience can be designed, the researchers now tried
some different structures, searching for a structure where the number
of cracks can be 'programmed' into the material.

It turned out that spiral-shaped chocolate metamaterials like the ones displayed above have quite interesting and tunable properties. Not only
does the number of windings directly control the number of cracks
when the material is pressed mechanically; the test panel could
also clearly distinguish between less and more cracks when eating
the chocolates. Moreover, sound recordings showed that the sound the
chocolates makes when being bitten reflects the number of cracks, adding
to an enjoyable eating experience.

The perfect piece of chocolate The final question was of course: is
designing an enjoyable eating experience a matter of trial and error,
or can nice edible materials actually be designed and fine-tuned
before creating them? The researchers found that with a well- chosen mathematical model, they can indeed optimize certain shapes of chocolates
with respect to, for example, their resistance to break when bitten from certain directions.

The design of edible metamaterials had not been studied before. The
new research opens the door to ways to design foods that are enjoyable
to eat - - and more generally, to design materials that optimize the interaction between humans and matter.


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


========================================================================== Related Multimedia:
* Chocolate_shape_samples ========================================================================== Journal Reference:
1. Andre' Souto, Jian Zhang, Alejandro M. Arago'n, Krassimir
P. Velikov,
Corentin Coulais. Edible mechanical metamaterials with designed
fracture for mouthfeel control. Soft Matter, 2022; 18 (15): 2910
DOI: 10.1039/ D1SM01761F ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220421141148.htm

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