Baking & Snack - September 2008 - 94

EXTRUSION TECHNOLOGY

Extruding
Circumstances
Whole-grain and co-extrusion product
trends drive the latest advances in
single- and twin-screw extrusion systems.
BY SHANE WHITAKER
ew developments in extrusion technology
make it easier to produce uniquely textured
and shaped snack foods. Cereal and snack food
processors are also using extruders to create
healthier snacks made with whole grains.
Ten to 15 years ago, it wasn't always clear when highpressure extrusion would be the best option for manufacturing particular products, but after years of R&D,
now it is generally understood which products should be
made using twin-screw extrusion, according to Paul Abbott, vice-president, sales and marketing, Baker Perkins,
Grand Rapids, MI. Thus, extrusion manufacturers are
currently focused on improving the performance of the
equipment rather than exploring its limits, he observed.
Equipment vendors have steadily made advances to
key areas important to users of extrusion technology
- performance, reliability and cost of ownership -
according to Ian Purvis, senior account manager, Baker
Perkins. "The truth is twin-screw extruders are a much
better bang for the buck now than they were five, 10 or
15 years ago," he said. "You get a lot more for the money
in terms of capital cost per pound of product output. Also,
the design, the efficacy of the machine, operator convenience and processing capabilities are all getting better
and better, and you should expect that to continue."
Low-pressure extrusion also underwent a number of
changes in recent years. Reading Bakery Systems (RBS),
Robesonia, PA, has manufactured low-pressure extruders for a half a century, and it recently improved its cutting systems to be stronger and more accurate in terms
of blade setups to cut multigrain and whole-grains
doughs so they fall cleanly onto the belt for baking,
according to John Eshelman, director of pretzel and
snack machinery sales, RBS.

SINGLE VS. TWIN. Extrusion processing options are
varied and include single-screw forming, twin-screw
cooking, co-extrusion and extrusion as a mixing process.
Extruders use high, medium or low pressure. Snack manufacturers must understand the various technologies and
equipment options to determine which extrusion system
might best meet their needs as they expand their product
portfolio. The extruder a bakery selects is always going to
be dependent on the products they want to produce.
Single-screw extruders use an auger to move product
and rely on the friction between the barrel and product
within the auger flights to work the ingredient mixture
and move it along. Single-screw extruders consume less
ᮡ Co-extruded products, including filled sticks, twin-filled bars and filled
"credit cards," continue to gain popularity.
BAKER PERKINS

ᮡ This solid-barrel extruder offers process flexibility through a modular
barrel design and a high-torque motor and gearbox combination.
BAKER PERKINS

September 2008 / BAKING & SNACK

Baking & Snack - September 2008

Table of Contents for the Digital Edition of Baking & Snack - September 2008