Reduction of process taste in sugar solution with carbon filtration
Josefine Cragnell
Department of Chemical Engineering, Lund University, P. O. Box 124, SE-221 00 Lund, Sweden
In this study different activated carbon products’ ability to adsorb impurities in beet sugar
solution are examined. The impurities arise in the sugar juice during the refining and cause an
unwanted additional flavour and hence the name process taste. Column experiments and
isotherm tests are performed in laboratory scale with various activated carbon products. The
used carbon product in the plant (Jacobi’s AquaSorb H200) is examined more thoroughly in
regard to empty-bed residence time and cycle time. All experiments are evaluated with sensory
analyses since the identity of the impurities is unknown and consequently no concentrations can
be measured. The sugar juice samples which were filtrated with Norit’s GCN 830 Plus,
Chemviron’s Aquacarb 607C and Jacobi’s AquaSorb CS appeared to have the lowest process
taste. The highest empty-bed residence time tested, 38 minutes, resulted in the lowest process
taste.
Introduction
Nordic Sugar in Arlöv is a sugar refinery which
among others produces sugar solutions. One of the
sugar solutions has a lower quality compared to the
other sugar solutions. This sugar solution is called
“smakförbättrad lösning” (SFL) and can be
translated to taste enhanced solution in English. The
SFL is produced in a different way and is sold to a
lower price. Before SFL is transported to the
customers a sensory analysis is performed. In the
sensory analysis a panel tastes the SFL. Sometimes
the SFL fails in the sensory analysis. It depends on
an additional flavour which has been obtained from
the refinery process in the plant. To overcome this
problem and to raise the quality of the SFL the
carbon filter in the plant is investigated.
The activated carbon used in the plant is
manufactured by the carbon company Jacobi and is
called AquaSorb H200. The carbon filter does not
remove the impurities satisfactory and it either
depends on that the carbon filter is poorly designed
or that the activated carbon in the filter has too low
affinity and selectivity for the target impurities.
Perhaps there are other carbon products that have
higher affinity and selectivity for the target
impurities. Therefore seven different activated
carbons from three different suppliers are examined
together with Jacobi’s AquaSorb H200. These
carbons are mentioned below together with their raw
materials.
 Chemviron’s CPG LF, Bituminous coal
 Chemviron’s Aquacarb 607C, Coconut
shell
 Jacobi’s AquaSorb CS, Coconut shell
 Jacobi’s AquaSorb H200, Bituminous coal
 Jacobi’s ColorSorb 5000, Lignite
 Norit’s GCN 830 Plus, Coconut shell
 Norit’s ROX 0,8, Coal
 Norits’s GAC 1240 Plus, Coal
The empty-bed residence time in the carbon filter
can be too short for the applied cycle. Too many
impurities then get breakthroughs before the cycle is
terminated. An empty-bed residence time of 38
minutes and 19 minutes are therefore compared with
the same cycle time.
The cycle time in the plant’s carbon filter can also
be too long for the applied empty-bed residence
time. It also leads to too many impurities get
breakthroughs. To investigate this, the carbon that
has been in the plant for a whole cycle is examined.
All experiments are evaluated with sensory
analyses since the identity of the impurities is
unknown and consequently no concentrations can be
measured.
Adsorption system
A simple adsorption system consist of one
adsorbate (one target impurity) a fluid (where the
impurity is dissolved) and one adsorbent, for
example activated carbon. The fluid enters the
column which contains the activated carbon. The
impurity adsorbs at first in the beginning of the
column bed. The adsorption moves further into the
column bed as more contaminated fluid flows into
the bed (1). The concentration of the impurity in the
fluid transfers ordinarily along the bed like a
sigmoid curve, due to internal and external mass
transfer resistance and axial dispersion. The
concentration of the impurity in the fluid along the
bed is often called concentration profile (2).
When the adsorption takes place near the end of
the bed, the bed is almost saturated and the impurity
soon begins to appear in the outflow. The
breakthrough starts to occur. Normally the cycle is
terminated before or in the beginning of the
breakthrough, depending on the purity requirement
(1).
When a simple adsorption system is evaluated
the sample collection begins right before the
breakthrough takes place.
The fluid at Nordic Sugar consists of a sugar
juice that contains many different impurities that
together give rise to the process taste. The
adsorption cycle is terminated when too many
impurities received breakthrough. In this system
some impurities get breakthroughs in the beginning
of the cycle and some later and some in the end of
the cycle. The breakthroughs occur in other words
continuously during the cycle. For this reason the
sample collection in this study starts from the
beginning of the cycle.
Activated carbon
Activated carbon is a porous adsorbent and the
pore size distribution is typically trimodal (3). The
large micro pore volume in the activated carbon
decides almost completely the capacity since it gives
rise to the large surface area (4). The surface area in
commercial activated carbon is often between 5001500 m2/g (5). The huge surface area and its relative
low price makes activated carbon the most
commonly applied adsorbent (6).
The surface of activated carbon is non-polar or
slightly polar. The slightly polar nature depends on
oxidized functional groups on the surface and
inorganic minerals in the carbon (4). The interaction
between the impurities and the surface of carbon
occur mainly through London forces and close-range
repulsion (6).
The selectivity of the impurities on the adsorbent
is due to their isotherms or their kinetics. The
isotherm competition is favoured when there is a
large difference between the impurities’ onecomponent-isotherms on the adsorbent (4). On
activated carbon the isotherm mainly depends on the
molar mass of the impurity, polarity of the impurity
and solubility of impurity in the fluid. An impurity
with larger molar mass has a superior affinity than
an impurity with smaller molar mass, with the
understanding that they have approximately the
same solubility in the fluid (6).
When a porous adsorbent is used, such as activated
carbon, the kinetic selectivity can be significant (3).
The kinetic selectivity occurs when an impurity
adsorb faster than the other. Generally this happens
as a result of a higher pore diffusion coefficient.
This effect becomes significant when the micro pore
size is comparable to the dimension of the adsobate.
An extreme case of kinetic selectivity is when the
adsorbate cannot enter the pores, which is called
steric hindrance (7).
Scaling down
In most cases when adsorption is applied the
impurities have favourable isotherms. That is when
mass adsorbate per mass adsorbent is higher than
mass adsorbate per volume fluid, during
equilibrium. If the bed is furthermore sufficient
deep, as it normally is in the industry, a constant
pattern is reached (8) (9). At constant pattern the
shape of the concentration profile is constant as it
travels along the bed (2). In this situation the
velocity in the carbon filter of the plant should only
be considered and kept in the scaling down process
since the shape of the concentration profile does not
change with the bed length. This is with the
understanding that the shorter bed (laboratory bed or
pilot bed) is deep enough to develop the constant
pattern (9) (10).
In this study the velocity is not maintained under
the scaling down process. Instead the empty-bed
residence time is maintained, although it is
reasonable to assume that the constant pattern
appears in the laboratory column. The reason for this
inconvenience is that the carbon suppliers have
given Nordic Sugar incorrect instructions and since
it was not possible to convince them, the scaling
down process had to be performed in that way.
Even though this is incorrect, it is possible to
compare the various carbon products since the
experiments are performed under the same
conditions. However, it is difficult to determine if
the result had been the same at the correct
conditions.
In the plant the empty-bed residence time of the
carbon filter is 19,2 minutes and the cycle time is
200 hours. If the velocity in the plant was to be
maintained the empty-bed residence time had been
2,26 minutes and cycle time had been 23,5 hours.
Sensory analyses
There are two different sensory methods,
analytical test and consumer test (11). The aim of
the sensory analysis is to analyse the samples and
not to get the consumers’ opinions about the
products. Therefore analytical test is used. Two
different types of analytical tests are often
mentioned in the literature, the difference test and
the descriptive analysis (12). In this study several
samples will be compared and since no scale has
been elaborated the difference test is chosen.
In the difference test, it is evaluated whether
there are differences between the samples or not.
The most common difference test is duo test and
triangle test. The panel that is used in the difference
test is called discrimination panel. The members of
the discrimination panel must have a special
sensitivity for the requested sensory property (11).
The panel that is used in this study is Nordic
Sugar’s own. The persons in the panel have been
selected after they have undergone extensive tests.
The tests investigated among others the persons’
sensitivity for the process taste.
The difference tests used in this study are duo
test and rank sum test. In the rank sum test the panel
is asked to rank the samples in respect to which
sample that taste most like a sugar solution. In the
duo test two samples are compared in regard to the
same sensory property.
During the performance of the rank sum test it is
important to make sure that not too many samples
are compared at the same time. This depends on that
the taste buds become saturated and the risk that the
panel members lose motivation increase. This also
concerns duo-test where a maximum of three duo
tests are applied during the same test session (12).
Duo test
Statistics
In this study one-sided duo tests are performed.
In one-sided duo tests the number of panellists who
thinks that A (A is the sample with most votes)
tastes most like a sugar solution is calculated and
then the total number of judges is also calculated.
To determine if A tastes significantly more like a
sugar solution than B a table which is calculated
from the binomial theorem is used. In the table the
critical value at a specific level of significance and
total number of judges are read. If the number of
judges that choose A correspond to the critical value
or if the number of judges that choose A is more, A
is significantly more like a sugar solution than B at
that level of significance (11).
Rank sum test
Serving
In this study Friedman’s test is used to examine
if the samples in the rank sum test come from the
same population. Friedman’s test is a non-parametric
statistical evaluation and is widely used in rank sum
tests within the sensory analysis.
In the test the parameter T is calculated
according to the equation below.
The sensory samples are served to the panel after
they have been pH adjusted with 5 M NaOH
solution to pH 6,8 and diluted with tap water to Rt 1
40. The temperature of the samples is 20 °C and the
sample volume is the same for all the samples. The
samples are served in random order to erase the
results which depend on the serving order.
Material
The samples are assumed to belong to a chisquare distribution. The T-value is compared to the
critical tabulated chi-square value which is read
from the number of degrees of freedom, k-1, and
significance level. When the T-value is larger than
or equal to the critical tabulated chi-square value the
null hypothesis can be rejected at that significance
level.
In Friedman’s test the null hypothesis is
formulated as below.
H0=The samples come from the same population i.e.
theirs medians represent the same population.
H1= At least two samples represent populations with
different medians.
In order to get the null hypothesis rejected it is
enough that two of the samples do not come from
the same population (13).
When the null hypothesis in Friedman’s test is
rejected it is desirable to investigate which of
samples that differ significant. To answer this
question the Fishers LSD is calculated according to
the equation below.
If the difference between the sums of rank for
two samples is more than the LSD-value the samples
differ significant from each other (14).
The input material, the beet sugar juice, is the
same for all subsequent experiments. The sugar juice
is collected after an ion exchanger and before the
carbon filters in the operating line. In order to get a
representative material the collection is performed
by extracting different fractions from the stream.
Every fraction is extracted in regard to how many
tons that have passed through the ion exchanger.
The extracted sugar juice is stored in a large
container with a capacity of one cubic meter. In
order to not let the sucrose undergo hydrolysis
during the storage it is necessary to raise the pH
from 3,2 to 4,85 since acid catalyses the reaction.
Below the irreversible hydrolysis reaction is
specified. As can be seen the sucrose breaks down
into fructose and glucose.
The experiments
The ideal approach would be to analyse each
activated carbon for a full column cycle. The column
tests would then have to be performed in parallel
since a cycle is 200 hours (when the residence time
is maintained). Unfortunately there were not so
many columns available which made it impossible.
Instead a column test was made with one carbon
product at a time and the tests were terminated after
an hour of trials. The reason for the short test time
1
Refractometric Dry Substance
(cycle time) was that the taste of the samples was
likely to change if they were stored too long in the
refrigerator.
In order to evaluate the different carbon products
further isotherm tests were performed on all
activated carbons.
All experiments, column tests and isotherm tests,
were carried out at 60 °C. Granulated activated
carbon was used in the column tests and the pH of
the input material was 4,85. In the isotherm tests
powdered carbon was used. The powdered carbon
products had been grinded by respectively carbon
supplier so that 95 % of the carbon mass went
through a 325 mesh sieve. In the first isotherm test
below the input material was pH adjusted to 3,2 with
5 M HCl. In the other isotherm tests the input
materials were pH adjusted to 3,5 with 5 M HCl.
The operating conditions were according to test 1
in table 1 when used and unused Jacobi’s AquaSorb
H200 were compared. The samples were evaluated
in sensory duo tests.
Isotherm tests
In order to ensure that the equilibrium was
reached between the impurities on the adsorbent and
the impurities in the sugar juice an evaluation of the
residence time was done with AquaSorb H200.
Three different residence times were compared, four
hours, six hours and eight hours. The samples were
evaluated in a sensory rank sum test. Below the
operating conditions for the three samples are given
Table 2. The test conditions are given.
Sampl
e
1
2
3
Column tests
In all column tests the experimental setup
revealed below was used.
Residence
time (h)
4
6
8
Carbon dose
(g/L)
40
40
40
pH
3,2
3,2
3,2
Sample
volume (L)
1
1
1
After the establishment of the residence time the
carbon dosage was analysed. Three different carbon
dosages were tested, 20 g/L, 40 g/L and 60 g/L. In
the table below the operating conditions are given.
The samples were compared in a sensory rank sum
test.
Table 3. The test conditions are given.
Sampl
e
1
2
3
The various carbon products that were compared
in the column tests were Chemviron’s Aquacarb 607
C, Chemviron’s CPG LF, Jacobi’s AquaSorb CS,
Jacobi’s ColorSorb 5000, Norit’s GCN 830 Plus and
Norit’s ROX 0,8. Test one in the table below
specifies the operating conditions of the column tests
when the carbon products were tested. The samples
were compared in sensory duo tests.
In the evaluation of AquaSorb H200 the
residence time was varied by varying the flow. The
test conditions is revealed in the table below. The
obtained samples were compared in sensory duo
tests.
Flow
(ml/min)
1
19,2
31,25
2
38,4
15,62
Bed
height
(cm)
39
39
pH
3,5
3,5
3,5
Sample
volume (L)
1
1
1
Table 4. The test conditions are given.
Residence
time (h)
6
Table 1. The test conditions are given.
Residence
time (min)
Carbon dose
(g/L)
20
40
60
The various carbon products were then examined
with the established residence time and carbon
dosage. The carbon products which were tested were
Chemviron’s Aquacarb 607 C, Chemviron’s CPG
LF, Jacobi’s AquaSorb H200, Jacobi’s AquaSorb
CS, Jacobi’s ColorSorb 5000, Norit’s GAC 1240
Plus, Norit’s GCN 830 Plus and Norit’s ROX 0,8.
The operating conditions in the isotherm tests were
the same for all carbon products and they are given
below. The samples were compared in rank sum
tests.
Figure 1. A schematic picture of the experimental setup is
shown above.
Test
Residence
time (h)
6
6
6
Carbon dose
(g/L)
60
pH
3,5
Sample volume
(L)
1
Result
Bed area
m2
Velocity
(m/s)
1,54 10-3
3,39 10-4
-3
-4
1,54 10
1,69 10
Column tests
The samples collected from the carbon filtration
with different activated carbons were evaluated by
comparing the samples in pairs (duo test). The result
showed that the sample which had been filtrated
with Chemviron’s Aquacarb 607C tasted significant
more like a sugar solution than the sample filtered
with Jacobi’s ColorSorb 5000. The sample filtered
with Jacobi’s AquaSorb CS tasted significant more
like a sugar solution than the sample filtered with
Norit’s ROX 0,8. Even the sample filtered with
Norit’s GCN 830 Plus tasted significant more like a
sugar solution than the sample filtered with
Chemviron’s CPG LF. The results were obtained by
calculating the number of votes for the sample with
the most votes. The critical value was then read in a
table. Below a summation is shown of the sensory
analysis.
Table 5. The compilation of the sensory analysis and
colour analysis are shown. The number of votes refers
to the number of judges who thought the sample tasted
more like a sugar solution.
Activated carbon
Chemviron’s
Aquacarb 607 C
Chemviron’s CPG LF
Jacobi’s AquaSorb CS
Jacobi’s ColorSorb
5000
Norit’s GCN 830 Plus
Norit’s ROX 0,8
Test
occasio
n
4
The
number
of votes
22
Mean
value
Colour
(IE)
5,5
52,8
4
4
3
11
19
8
2,8
4,8
2,7
16,7
57,6
19,8
3
2
14
3
4,7
1,5
53,7
28,4
Below the sensory results are revealed from the
column tests then new and used AquaSorb H200
were compared and when AquaSorb H200 with two
different residence times were compared.
Table 6. The compilation of the sensory analysis and
colour analysis are shown.
Duo test, Which sample has the highest process taste?
AquaSorb H200 New V.S
Number of
Colour
AquaSorb H200 used, T=19,2
votes
(IE)
7
AquaSorb H200 New
38,9
12
68,6
AquaSorb H200 used
19
Total
No significance at 5 % significance level. It requires 14 identical
answers for 19 judgments to obtain a significant result at 5 %
significance level.
AquaSorb H200 T=19,2 V.S
Number of
Colour
AquaSorb H200 T=38,4
votes
13
AquaSorb H200 T=19,2
38,9
6
AquaSorb H200 T=38,4
22,9
19
Total
No significance at 5 % significance level. It requires 14 identical
answers for 19 judgments to obtain a significant result at 5 %
significance level.
Isotherm tests
In the evaluation of the residence time a sensory
rank sum test was performed. The Friedman’s
parameter T was calculated to 3,25 and the critical
tabulated chi-square value for 2 degrees of freedom
and 5 % significant level was read to 5,99. The null
hypothesis could not be rejected since 3,25 are less
than 5,99. Therefore, there was no significant
difference between the three residence times.
Table 7. The compilation of the sensory analysis is
given below.
Number of people in the sensory analysis that think
the sample tastes most like a sugar solution. Number
1gives most like and number 3 gives less.
1
2
3
3
3
2
4h
5
1
2
6h
0
4
4
8h
Invert quota
4,614
4,274
3,737
A rank sum test was performed in the carbon
dosage evaluation.
The result showed no
significance since Friedman’s parameter T was 0,33
which was lower than the critical tabulated chisquare value for 2 degrees of freedom and 5 %
significant level, 5,99. Below a summary of the
sensory analysis is shown.
Table 8. A summary of the sensory analysis and the
invert quota are given.
Number of people in the sensory analysis that think the
sample tastes most like a sugar solution. Number 1gives
most like and number 3 gives less.
1
2
3
2
1
3
20 g/L
1
5
0
40 g/L
3
0
3
60 g/L
Not filtered
Invert
quota
4,75
3,25
2,90
2,55
The isotherm tests with different carbon products
were analysed with rank sum tests and one duo test.
All carbon products could not be compared in one
rank sum test and it was therefore necessary to make
several rank sum tests. Below a compilation of those
can be seen.
Table 9. A compilation of the sensory analysis is given.
The question asked was which sample tasted most like
a sugar solution.
Carbon
Test
occasion
Mean
value
Best
1
The
numbe
r of
votes
18
Chemviron’s
Aquacarb 607 C
Chemviron’s CPG LF
Jacobi’s AquaSorb
H200, 60 g/L
Jacobi’s AquaSorb
H200, 40 g/L
Jacobi’s AquaSorb CS
Norit’s GCN 830 Plus
Norit’s GAC 1240 Plus
Norit’s ROX 0,8
18
X
1
1
19
21
19
21
X
1
32
32
1
2
1
2
25
29
28
68
25
14,5
28
34
X
The result showed that the sample filtered with
Norit’s GCN 830 Plus tasted significant more like a
sugar solution than the samples filtered with Jacobi’s
AquaSorb CS, Norit’s GAC 1240 Plus and Norit’s
ROX 0,8. AquaSorb H200, 60 g/L, tasted
significant more like a sugar solution than the
sample filtered with Norit’s ROX 0,8.
Norit’s ROX 0,8 tasted significant lesser like a
sugar solution than the samples filtered with
Chemviron’s 607C, Norit’s GCN 830 Plus and
Chemviron’s CPG LF.
Jacobi’s AquaSorb H200, 40 g/L, tasted
significant lesser like a sugar solution than Norit’s
GCN 830 Plus, Chemviron’s 607C and Chemviron’s
CPG LF.
Table 10. The compilation of the sensory analysis is
given.
Which sample taste most like a sugar
solution?
Number of
votes
Jacobi’s ColorSorb 5000, 60 g/l
Norit’s GAC 1240 Plus, 60 g/l
5
0
No significance
The sample that had been filtered with Jacobi’s
ColorSorb 5000 did not taste significant more like a
sugar solution than the sample filtered with Norit’s
GAC 1240 Plus, see table above.
Discussion
Column test with AquaSorb H200
When the empty-bed residence time was varied
in the column tests with AquaSorb H200 the higher
residence time resulted in a lower process taste. The
colour analysis also showed that the carbon filtration
with higher residence time resulted in a higher
colour reduction. This result is consistent with the
theory, that a higher residence time results in a later
breakthrough and hence fewer substances get
breakthrough during the cycle (with the same cycle
time). Therefore fewer impurities are present in the
sample and a lower process taste is obtained.
The result was not significantly, it fell on one
vote. However, it is possible to draw a conclusion
since the result was relatively unequivocal since 13
out of 19 were of the same opinion. It is possible
with great certainty to assume that the process taste
can be reduced, with the carbon being used today, by
increasing the residence time when the same cycle
time is used.
In the comparison between new carbon and used
carbon the result was that the sample which had
been filtrated with new carbon had almost a
significantly lower process taste than the sample that
had been filtrated with used carbon. The result is
reasonable since the new carbon is free from
impurities in the beginning of the experiment and
has therefore a higher capacity left. The result
showed that the used carbon had lower capacity
compared to the new carbon. The result also showed
that the used carbon had little capacity left since
seven out of nineteen said that the juice that had
been filtrated with used carbon had a lower process
taste than the new carbon.
Isotherm test
In the evaluation of the residence time in the
isotherm test most thought that the sample that had
been filtrated with six hours residence time tasted
more like a sugar solution. Six hours residence time
will therefore be used. The result was not significant
which means that the result may be due to chance. It
was therefore not certain that six hours residence
time was enough to reach equilibrium.
The invert quota of the input material was
approximately 2,5 and during the experiment the
invert quota increased. In order to avoid a high
invert quota in the future the pH of the juice was
raised to 3,5.
Three different carbon dosages were then
examined with six hours residence time. The result
from the sensory analysis was obscurely because the
samples were perceived as very similar. The aim of
the isotherm tests was not to find the carbon which
adsorbs the most impurities with the lowest carbon
dosage. Instead it was to find the carbon that adsorbs
most impurities regardless to carbon dosage. The
highest carbon dosage was therefore selected, 60
g/L. In addition, the highest carbon dosage resulted
in a lower invert which was probably due to the
higher adsorption of glucose and fructose.
Comparison between the various carbon products
In the column tests the juice samples that had
been filtrated with Chemviron’s Aquacarb 607 C,
Jacobi’s AquaSorb CS and Norit’s GCN 830 Plus
got a lower process taste. All of these three carbons
are made of coconut shell. The result depends on
that these carbon products have a greater proportion
of micro pores than the other carbons. The smaller
molecules diffuse faster into these than the larger
molecules and some cannot enter. In this way,
molecules with small molar mass can compete with
molecules that have larger molar mass. The result is
very distinct since the carbons which reduce the
process taste the most reduce the colour worse.
Unfortunately Jacobi’s AquaSorb H200 was not
tested in this experiment since it was out of stock. It
is therefore impossible to determine how AquaSorb
H200 is in comparison to the other carbons in the
column tests.
In the isotherm tests the residence time is
assumed to be sufficient in order to reach the
equilibrium. Since the time needed to reach
equilibrium is applied the kinetics is not important.
In general, the equilibrium should benefit the
molecules with large molar mass because they have
a higher affinity and therefore a more favourable
isotherm. However, there are times when molecules
with larger molar mass cannot enter the micro pores.
This is to the benefit of small molecules. The results
of this test showed that the samples which had been
filtrated with Norit’s GCN 830 Plus, Chemviron’s
Aquacarb 607 C and Chemviron’s CPG LF tasted
most like a sugar solution. Jacobi’s AquaSorb H200
was included in this test and resulted in a higher
process taste with same carbon dosage.
Many members of the panel said after the
sensory analysis that the filtrated sugar juice tasted
very similar to a sugar solution. They were referring
to the three best samples in the isotherm tests. This
comment has never been heard before. The result
indicates that the equilibrium capacity provides the
best separation of the undesirable taste molecules.
Another important comment is that an increasing
in the pH of a fluid that is filtrated with activated
carbon normally reduces the adsorption of the
impurities. This probably also affects the result since
all the experiments were not performed at the same
pH. It is probably possible to increase the adsorption
of the impurities in column tests by decrease the pH
in the sugar juice.
Conclusion
The following conclusions can be drawn from
the results:
 The carbons Norit’s GCN 830 Plus and
Chemviron’s Aquacarb 607 C have a high
selectivity of the target impurities in the
column tests because of their equilibrium
isotherms.

Jacobi’s AquaSorb CS has probably a high
selectivity of the target impurities in the
column tests due to the kinetics.
 Chemviron’s CPG LF has an equilibrium
capacity which benefits the flavour
molecules while the kinetics benefits the
colour molecules.
 The process taste can be reduced by
increasing the empty-bed residence time
when the same cycle time is used.
Future work
It would have been desirable to evaluate the
carbons which resulted in the lowest process taste
more profound, and then compare them with the
currently used. The column tests had then been
performed over an entire cycle which is 23,5 hours
when the scaling down process is done properly. The
pH of the sugar juice had also been adjusted to 3,5.
Nomenclature
= Number of treatments, number of samples and number
of columns.
= Least significant difference.
= Number of blocks, number of persons and number of
rows.
= The sum of rank numbers for each treatment
= Friedman’s parameter.
= The quantile of t- distribution.
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Received for review August 27, 2010