Baking & Snack - May 2019 - 104

CO-EXTRUSION

Sanitation standards
continue to climb higher,
and equipment is rising
to meet the bar with
sanitary design, which
makes equipment faster
and easier to clean.
Reiser

of equipment. When
working with multiple fillings
in one product, this challenge can become
even trickier. The greatest pitfall in balancing it all is
preventing the filling from leaking into the dough or
even outside of the shell. While low-moisture fillings
often work best to prevent this situation, co-extruders
might have to work with a range of viscosities.
To produce an intact final product that consumers
will not only accept but also enjoy, the equipment must
preserve the integrity of the filling and the outer shell,
both of which have very different needs. Controls and
technology can help bakers and snack makers achieve
this balance. Clextral uses a combination of precision
extruder control and independent local control for the
filling equipment to respond to the divergent demands
of shell and filling.
For the dough, Clextral's Evolum extruders feature
independent heating and cooling circuits in each modular barrel segment. These circuits are controlled by the
company's proprietary Advanced Thermal Control
(ATC), which continuously monitors and adjusts to
changes in production parameters.
"We design the screw configuration to provide the
correct cooking-to-resting ratios for the dough, and
inside the twin-screw extruder barrel, the self-cleaning
screw action ensures complete mixing of the ingredients
and transformation of the starch," Mr. Maller explained.
Clextral also uses a precisely controlled system to
protect the filling integrity with local control on the filling platform that is integrated with the plant supervision system. After ingredients are metered and mixed in
the stainless-steel filling tank, strict temperature control
and a recirculation loop maintain the filling's optimum
viscosity before being extruded into the shell.

104 Baking & Snack May 2019 / www.bakingandsnack.com

Choosing the proper equipment configuration is also critical in preserving dough
and filling integrity. Handtmann tailors its
co-extrusion systems to the manufacturers'
product, combining different machine specifications to optimize dough and
filling handling. "We can offer a
dough filler to handle an airy,
soft dough that will maintain the structure during the
co-extrusion process in
combination with a filler
that will handle stiff and
dry or viscous fillings," said
Cesar Zelaya, bakery sales and
technology manager, Handtmann.
When tailoring co-extrusion equipment to
the dough and filling, it's important to approach them
separately, as their needs are so different, according to John
McIsaac, vice-president, strategic business development,
Reiser. "We work to make sure the dough is fully developed as it is formed around the inner filling," he said. "This
involves both work on the Vemag machinery and the coextrusion process." Reiser's bakery specialists collaborate
closely with the baker or snack manufacturer to develop
the appropriate equipment setup before optimizing the
process to create the desired dough volume and crumb.

Gentle co-extrusion is key
to maintaining the integrity
of the entire product, and
it's something suppliers
have had to adapt the
equipment to for the baking
and snack industries.
"Each customer is after certain attributes that make
their product unique to them," Mr. McIsaac said. "We
certainly have the equipment and technology, but more
importantly, we have the people and expertise to work
with our producer customers. Our bakery specialists
first learn about the customer's product and the process.
We then match the equipment to the process."
When approaching the filling, Reiser's bakery specialists start with the finished product and work backward with the intention of maintaining the filling's
final quality. "The filling is often made up of larger

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