The nose that sniffs food in University of
Georgia labs never catches a cold. The electronic nose,
or e-nose, is a machine that
can analyze foods in much the same way humans do.
“When
you sense substances in
your nasal cavity, you are really sensing flavors by mouth
and nose,” said Anna
Resurreccion, a UGA sensory
specialist. “In the same way, the e-nose analyzes the
flavors in the head space above
a food sample.”
Although the e-nose can be used to predict human sensory
responses, it must first be
trained by human panelists.
“We first have a consumer test with humans to determine
which food samples are
preferred and which are unacceptable,” Resurreccion
said. “Next the measurements
from the consumer test are analyzed along with data from the
e-nose.”
Mathematical models are then developed that allow e-nose
results to be used in future
tests.
The e-nose can also be used to quantify aromatics or
flavors in foods. For these tests,
10 trained panelists first analyze the food product. Next
tests are run using the e-nose’s
head-space analysis and the results are compared to human
responses.
THE
ELECTRONIC ‘NOSE’
sniffs out particular odors and smells in a way similar to a
human nose, said Anna
Resurreccion, UGA sensory specialist at the Georgia
Experiment Station. But it can go one
step further and analyze what components the odor contains
and how much of the component
is in the overall smell. It won’t entirely take the place of
human test panels, she said,
but it will cut down on those time- and labor-intensive
studies. (Photo courtesy the
UGA College of Agricultural and Environmental Sciences.)
Resurreccion said the e-nose will drastically reduce the
number of consumer tests
needed for routine food testing.
“We use sensory tests with humans when there are no machines
available to simulate
human responses,” she said. “In terms of flavor and acceptance,
the e-nose is a
means to get rapid results without having to do numerous sensory
tests which are both
labor- and time-intensive.”
The e-nose doesn’t totally replace people in sensory
testing. “We still need
people to provide the initial data to calibrate the equipment,”
Resurreccion said.
“The e-nose just reduces the number of sensory tests.”
Over the past year, UGA food scientists have used the e-nose
in sensory tests on
carrots and peanuts. Working with Georgia’s new carrot industry,
scientists used the
e-nose to classify high-quality and low-quality carrots.
“The lower-quality carrots are less sweet and have a harsh,
bitter, carroty,
astringent flavor,” Resurreccion said. “These carrots must be
sorted out and
sold under a generic label or used in juices, rather than being
sold under the Georgia
Sweet Carrots brand name.”
Using the e-nose and consumer panelists, UGA researchers
compared Georgia carrots to
Florida- and California-grown carrots.
“We identified some Georgia varieties that were comparable to
California varieties
and most Georgia varieties beat out Florida carrots,”
Resurreccion said.
“Georgia growers now know which varieties grow best and should
compete well in the
market.”
Resurreccion said methods are also being developed in Florida
to use the e-nose to
determine quality in seafood.
“Measurement of seafood qualities is sensory-based, so the e-
nose should work
well,” she said. “It could someday be used in rapid sensory
tests in packing
plants.”
Three companies make the device. UGA’s e-nose is on loan from
Neotronics Scientific,
Inc., of Gainesville, Ga.
