Secret to Bad-Tasting Diet Sodas Found
By LiveScience Staff
It's
the feel of diet soda in the mouth that
makes it taste crummy, not the flavor of
the artificial sweetener, studies suggest.
Consumers
claim they dislike the taste of aspartame
and Splenda, but research by two University
of Illinois food
scientists shows that swillers
of diet and regular soda are also influenced
by a subtle factor called mouth-feel.
Mouth-feel
refers to a food or beverage's body, fullness
and thickness, the scientists say, and the
presence of high-fructose corn syrup in
regular
soda and its absence in diet
might be a distinguishing factor for discerning
drinkers.
Drink
up!
Soo-Yeun Lee and Shelly Schmidt trained
12 people for four weeks to use a 15-point
scale to rate the characteristics that contribute
to the mouth-feel of diet and regular soda.
The panelists became so skilled that they
were able to accurately identify significant
differences in the mouth-feel of 14 samples
that sensitive lab instruments identified
as very small.
"We
worked with solutions of sucrose and high-fructose
corn syrup, asking panelists to detect when
beverages began to differ from water in
mouth-feel," said sensory scientist
Soo-Yeun Lee. "And they were able to
accurate identify varying degrees of viscosity
on our 15-point scale."
"The
human mouth cavity appears to be a super-rheometer
(the lab instrument that measures viscosity
or thickness)," said Lee's colleague
Shelly Schmidt.
Lee,
Schmidt and S.M. Kappes, Lee's graduate
student at the time, co-authored four studies
about the sensory characteristics of diet
beverages
which were recently published in the Journal
of Food Science.
Halo
and horns effects
Enjoying
food is complex, involving not only taste
and mouth-feel, but also aroma, vision and
hearing.
"If
you bite into an apple and it doesn't crunch,
it affects your perception of the way the
apple tastes," Lee said. "And
if a beverage doesn't feel right in your
mouth, that affects your perception of the
way the beverage tastes too."
If
a food attribute enhances the flavor "sense"
that humans have of something eaten, sensory
scientists call that a "halo effect."
If the attribute diminishes the flavor sense,
scientists say it has a horns effect.
When
color was added to lemon-lime beverages,
panelists believed that the beverage had
more body, meaning the color conferred a
halo effect. But the color also led tasters
to think the beverage had less carbonation,
which it did not, meaning the color also
conferred a horns effect, Lee said.
"We
think the lemon-lime flavor, which is exciting
to the mouth, helps mask the mouth-feel
difference, and that's why diet lemon-lime
drinks were perceived as tasting more like
their non-diet counterpoint than cola-flavored
drinks," Lee said.
"It's
probably also the reason the new lime diet
colas are so popular," Lee
said. "The sour taste of the lime works
with the carbonation to keep the mouth busy
so the consumer doesn't notice the lack
of body as much."
Seeking
a new ingredient
Eventually,
the scientists would like to find an ingredient
that gives body to diet soft drinks without
adding calories or other unpleasant side
effects.
"We
need to find an ingredient that has no calories
but gives the same mouth-feel as sucrose,"
Lee said.
This
ingredient would make diet drinks more appealing.
"If we could make diet soda taste better,
it would be a big step in fighting the obesity
epidemic," Schmidt said.
"Many
people know they should cut calories, but
they won't drink diet pop because they don't
like the taste."
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