World Grain - October 2014 - 54

FEATURE: THE NEW LOOK

Ultrasound ... for dough?
Scientists looking at dough performance usually employ rheological methods,
which measure the deformation of matter. Ultrasound probes matter's interior and,
in the case of dough, provides information about the bubbles that determine finished
product texture.
Although rheology is usually the cereal scientist's choice, ultrasound deserves consideration, too, according to Martin Scanlon, PhD, professor of food technology, department of food science, University of Manitoba, Winnipeg. He recently explained how
low-intensity ultrasound could help predict dough's mechanical performance during
mixing, sheeting and extrusion.
Ultrasound methods measure how fast sound propagates through a substance, in
this case, through dough, and how effectively it dissipates. It can probe the size and
prevalence of bubbles because their density differs from the dough matrix. Doughs with
a greater number of bubbles are softer, and doughs developed by sheeting will have
larger bubbles.
"Bubble sizes in dough can potentially be determined using ultrasonic techniques,"
Dr. Scanlon said. "All rheological tests on dough are affected by bubbles, and more
importantly for the breadmaking process, all dough process steps are affected by the
bubbles a dough contains."
to help do the gluten-free job. The
Mixolab measures the consistency of
doughs during mixing and under changing temperature. These results describe
starch gelatinization and retrogradation
- factors in shelf life. Mixing under
constant temperature gives information
on changes in water level, consistency,
stability and other rheological factors.
The second instrument Chopin recommends is the Rheo F4. It measures
the pressure within a sealed temperature-controlled tank containing a dough
sample. Its results describe total gas production (a.k.a. yeast activity) and retention of that gas and, thus, measure characteristics of dough during proofing. Gas
retention is lacking in gluten-free doughs
and causes complex problems with volume and baking performance. Protocols
can be customized to handle yeast-raised
gluten-free products. By knowing the
dough's tolerance, the baker can set up
the oven to properly bake them. Its information also helps optimize proofing conditions and mixer settings.
THE OTHER ROAD
Wheat's protein enables creation of
the light, airy texture that makes many
baked foods so popular. "But protein
content does not guarantee flour perfor54

mance," Shadow observed. "Different
types of end products require flour with
different characteristics."
The Perten Glutomatic measures gluten
quality in flour, wheat, durum and semolina. It provides a simple test, suitable for
use at grain or flour receiving stations.
"Results of this test help wheat millers test
flour streams for gluten formation quality
and quantity," Shadow said. "The results
are used to calculate flour blends and vital
wheat gluten addition."
For those who want to dig deeper into
the protein performance of their flours,
the Brabender GlutoPeak instrument reports the performance curve of the tested material, unfolding the complexity of
aggregation and breakdown of the gluten network. A small quantity of flour, 7
to 9 g, is mixed with water, and the test
is run for one to 10 minutes, depending
on the sample. Strong flours, such as
those suitable for bread or pasta, show
high torque and short gluten aggregation time, also termed peak maximum
time (PMT). Weak flours, as are used for
cookies and crackers, reveal low torque
and long PMT, and very weak flours for
making wafers or batters exhibit much
delayed PMT or no aggregation at all.
The company's GlutoPeak provides
a quick test method to check delivered

As tested by a gluten quality instrument,
strong flours show strong torque. Photo courtesy
of Brabender.

grain or flour in relation to its quality
specs. "The results will help the miller
to control and optimize the receipt of
grain," said Marc Gelautz, marketing,
Brabender GmbH & Co. KG, Duisburg,
Germany. "He can decide quickly which
quality the grain has. Later in the process,
the instrument can help find the best mixtures of flour for requested quality."
The instrument is easy to handle in
daily use, taking only minutes to perform its analysis. "Every new flour can
be checked very quickly," Gelautz said.
"For R&D, it would be also very helpful because of the short test times when
new types of flour are checked." The
GlutoPeak correlates well to bake tests,
thus minimizing the number of such
procedures needed.
Digging deeper into protein performance, the Bastak 6100 gluten washer
gives results that determine the best use
for a given lot of wheat or flour. "After

Two flour samples can be tested for their gluten levels at once in this automatic washing
system. Photo courtesy of Bastak.

analysis by this instrument, the user can
determine the best use - baking, feed
or other products," said Suzan Kizilok,
foreign trader and food engineer, Bastak
October 2014 / World Grain / www.World-Grain.com

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World Grain - October 2014

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