Why Diet Soft Drinks? - Anton

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Why Diet Soft Drinks?
Nowadays, sugar-sweetened soft drinks are consumed in numerous households worldwide.
They represent a considerable contribution to the total daily intake of calories, but do not
contribute to a person's feeling of satiety. Several studies were undertaken to shed light on
the effects of soft drink consumption on health. The literature cites a study carried out in
the US that found that the consumption of soft drinks sweetened with sugar is connected to
serum uric acid levels. Another study showed that obesity and type 2 diabetes in the United
States increased alongside the rise in the consumption of soft drinks that contain sugar.
by KARIN BIEBERNIK and KLAUS RITTSTIEG (co-author)
It is no wonder that an increasing
consciousness regarding calorie intake
went side-by-side with an increasing
demand from consumers for caloriereduced soft drinks. The requirements
for constant product quality remained
unchanged, resulting in the demand for
instrumentation to specifically monitor
calorie-reduced soft drinks.
The concentration of the product after
syrup dilution and addition of carbon
dioxide was the main issue when it came
to beverage analysis and monitoring
of constant product quality. Online in-
strumentation is already widely used[1],
but instrumentation for measurements
on bottled or canned products in the
laboratory is also in demand.
At present, diet soft drinks are gaining
more and more market share in many
countries. This goes hand-in-hand
with an increased demand for a fast
measuring method for the quality control of these products. Considering
that the composition of these diet soft
drinks varies greatly as far as flavor,
sweeteners and other additives are
concerned, this demand represents a
PBA-SD Generation M Packaged Beverage Analyzer for Regular and Diet Soft Drinks.
PFD
DietQC
TM
ME
big challenge for innovative suppliers of
laboratory equipment.
The solution for soft drinks
with and without sugar
While the density measurement of soft
drinks that contain sugar is a frequently
performed and well-known procedure,
the measurement of diet soft drinks
proves to be more difficult to accomplish.
As mentioned earlier, the composition
of diet soft drinks can vary widely. For
this reason, a method was needed that
allows the reduction of the number of
analyses with the laboratory reference
method. The goal was to come up with
an easier and faster alternative method
that requires only an occasional check
measurement using the laboratory
reference method in-between: a reduced
amount of ref-erence determinations
makes the lives of operators easier in
their day-to-day routine.
This alternative method that allows
correlation with the reference methods
was realized in the form of a PBA-SD, a
Packed Beverage Analyzer for Regular
and Diet Soft Drinks. The PBA-SD
allows the correlation to the laboratory
reference methods and provides quality
control of soft drinks with and without
sugar. A PBA-SD Generation M consists of
a DMA 5000 M density meter, a CarboQC
ME beverage carbonation module, a
PFD filling device and a DietQCTM ME
measuring module. A PBA-SD measuring
system is calibrated against the reference
laboratory meth-ods of the respective
beverage (compare Table 1).
CarboQC ME
DMA 5000 M
Sources: Anton Paar GmbH
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drink Technology + Marketing · June 2011
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Table 1: Some common diet beverages and laboratory reference
methods for the determination of the monitored substance.
Beverage
Monitored substance
Laboratory reference method
Cola diet beverage
Phosphate
Photometric method or
ion chromatography
Cola diet beverage
Caffeine
HPLC
Most diet beverages
Total acids
Titration
The measurement of colorless and
turbid diet drinks is performed via a
density determination of the highest
precision with a DMA 5000 M density
meter. Typical diet soft drinks only show
small density differences in the range of
0.001 g/cm2 when compared to water.
Extensive tests showed that this small
density increase can be accurately determined by a DMA 5000 M density
meter. The determination takes only
five minutes and meets the very high
requirements for repeatability.
The vast majority of diet soft drinks
is colored. A suitable complement
that reduces the measuring time and
increases repeatability was found in the
DietQCTM ME measuring module.
Measuring principle of DietQCTM ME
DietQCTM ME is a colorimeter that determines the light absorption in the
spectral range of visible light. Based on
the DietQCTM ME measurement, the diet
concentration of cola beverages and
other colored diet drinks is determined.
A thermostatted measuring cell ensures
fast and reproducible results.
Laboratory measurement
for multiple demands
A daily zero check is carried out to
eliminate salinity influences of process
water. This check can be performed
within five minutes by the operator. If
required, an adjustment of the PBA-SD
is made with process water.
As there is no absolute method for
measuring the diet concentration,
the adjustment of a PBA-SD system
is performed with the respective
laboratory reference method. This allows precise concentration adjustment
for each type of diet drink. A new
drink Technology + Marketing · June 2011
measuring method for each diet drink
type is automatically created and saved
by the master instrument.
Direct sampling from a closed sample
container, be it a glass bottle, PET
bottle or can, is performed by means
of the PFD filling device. The PFD filling
device allows filling under pressure.
This renders degassing of the sample
obsolete.
As the amount of dissolved CO2 affects
the density, a CO2 correction needs to
be performed. This is achieved with
a CarboQC ME carbonation module.
CarboQC ME determines the dissolved
CO2 content. The CO2 result is used to
mathematically compensate the CO2 influence on the density result.
Depending on the selected output
information on the DMA 5000 M screen,
information on density, CO2 content,
diet concentration as well as sample
temperature are displayed.
diet soft drinks are measured by the
high-precision DMA 5000 M with CO2
correction. Colored diet soft drinks are
determined by a temperature-controlled
high-precision color measurement. This
method does not show any crosssensitivity to process water salinity.
Modularity scores
PBA-SD systems are user-friendly and
do not require sample preparation such
as degassing. The return of investment
manifests itself in the omittance of
chemicals. These systems also save
the operators time and effort. Already
existing PBA-S systems can easily
be upgraded due to their modular
setup. The optional use of a Soft Drink
Analyzer M, a combined density and
sound velocity meter, instead of the DMA
5000 M is planned for the imminent
future: this combination will allow the
additional determination of fresh °Brix
and inverted °Brix of soft drinks that
contain sucrose which is subject to the
sugar inversion process.
Further plans for future extensions
comprise the addition of modules for the
simultaneous measurement of dissolved
oxygen or pH. This modular concept
allows full flexibility for possible future
requirements.
Key No. 00000
References
[1]
K. Ghanaviztchi, Immediate Startup for Diet
Drinks, drink Technology + Marketing 4/10,
pp 16 – 19.
Numerous measurements with different
soft drink samples showed that PBA-SD
systems allow the determination
of diet soft drinks as well as soft
drinks containing sugar. Not only the
simultaneous measurement of °Brix,
the diet concentration of colored and
colorless samples and of CO2, but also
the simple operation and speed of
determination, e. g. three minutes for
cola diet drinks, render this measuring
system a perfect tool for a soft drink
producer's quality control laboratory.
It is easy to use, and its user-friendly
touchscreen features are an additional
asset.
The °Brix content of soft drinks that
contain sugar and turbid or colorless
The Authors
Karin Biebernik and Klaus Rittstieg (co-author)
are both working for Anton Paar GmbH in Graz,
Austria, www.anton-paar.com.
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