Continuous production of oligofructose syrup from Jerusalem artichoke juice by immobilized endo-inulinase

Article abstract of DOI:10.1016/j.procbio.2010.08.028

A commercially available endo-inulinase from Aspergillus niger was successfully immobilized onto a chitin carrier with 66% yield. The immobilized endo-inulinase showed maximal activity at 65 °C that was 5 °C higher than the optimum temperature of the free

Full text of DOI:10.1016/j.procbio.2010.08.028

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Process Biochemistry 46 (2011) 298–303
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Process Biochemistry
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Continuous production of oligofructose syrup from Jerusalem artichoke juice by
immobilized endo-inulinase
Quang D. Nguyena,∗, Judit M. Rezessy-Szabóa, Bálint Czukorb, Ágoston Hoschkea
a Department of Brewing and Distilling, Corvinus University of Budapest, H-1118 Budapest, Ménesi út 45, Hungary
b Central Food Research Institute, H-1022 Budapest, Herman Ottó út 22, Hungary
a r t i c l e i n f o
a b s t r a c t
Article history:
A commercially available endo-inulinase from Aspergillus niger was successfully immobilized onto a chitin
carrier with 66% yield. The immobilized endo-inulinase showed maximal activity at 65 ◦C that was 5 ◦C
higher than the optimum temperature of the free enzyme. Also, the optimum pH shifted from 4.5 to 5.0
for free form and 5.5 to 6.0 for the immobilized form. The immobilized endo-inulinase was stable at 4 ◦C
for at least 1 year. The residual activity of 90% and 95% of free and immobilized enzymes were recovered
after 5 days of incubation without substrate at 60 ◦C and pH between 4.5 and 6.5. Kinetic parameters
(Km and Vmax) for free and immobilized endo-inulinase were 2.04% (w/v) and 80.88 U/mg protein, and
2.19% (w/v) and 291.58 U/g support, respectively. The half-life time of immobilized endo-inulinase in
a packed-bed column reactor was estimated to be 48 days. A continuous production system of inulo-
oligosaccharides (IOS) from inulin and Jerusalem artichoke (JA) juice was set up and operated. Using this
system, syrups with high IOS content (from 35% to 65%) were successfully prepared.
Received 21 December 2009
Received in revised form 31 August 2010
Accepted 31 August 2010
Keywords:
Inulinase
Inulo-oligosaccharides
Prebiotics
Immobilization
Bioconversion
© 2010 Elsevier Ltd. All rights reserved.
1. Introduction
subsequent stimulation of growth of Bifidobacteria. The effects of
fructo-oligosaccharides (DP2–4), oligofructose (DP2–8), and mildly
Oligo- and polysaccharides that contain specific ␤(2 → 1) gly-
cosidic linkages have an important role in nutrition, because the
upper part of the human intestinal tract lacks enzymes that cleave
these linkages [1]. Inulin and fructo-oligosaccharides (FOS) are
known as non-digestible food ingredients that beneficially affect
the health status of a human body by selectively stimulating the
growth and/or activity of bifidobacteria already resident in the
colon, considered to be prebiotic [2]. Many health-beneficial effects
of fermentable fructans, especially the pentamers (DP5) and the
hexamers (DP6) have been reported including the prevention of
diabetes, cancer and the control of lipid metabolism [3–6]. Prebi-
otic effectiveness of inulin-type fructans depend not only on the
dietary dosage, but also on the degree of polymerization (DP).
Coudray et al. [7] reported that only the combination of oligofruc-
tose (DPav 4) and HP-inulin (DPav 25) at 1:1 ratio resulted in
synergistic effects on internal calcium absorption and balance in
rats. Relating to the growth and utilization of inulin-type fructans,
Biedrzycka and Bielecka [8] found that the effects of highly poly-
merized inulins were more diverse and depended on the presence
of other bacteria to initiate degradation, followed by the possible
polymerized inulin (DP9–22) were evident than the effects of HP-
inulin [9]. The ␤(2 → 1) fructans with a chain length of up to 10
residues are soluble and particularly ‘bifidogenic’ [1]. Moreover,
there is no doubt that carbohydrates with small molecular size are
able to pass through a cell wall easily and serve as a substrate for
probiotic bacteria. Long chain inulins (10–65 monomers) are poorly
soluble in water and have less pronounced bifidogenic properties
[1]. The utilization of these long chain inulins are expected to more
time in the colon. Nevertheless, the relationship between the DP of
fructans and prebiotic effects has not been clearly defined.
Endo-inulinase (2,1-␤-d-fructan fructanohydrolase, EC 3.2.1.7)
cleaves the internal ␤(2 → 1) fructosyl linkages of inulin to produce
short-chain oligofructose/inulo-oligosaccharides (IOS). In recent
years, some researchers have concentrated their efforts on sepa-
rating endo-inulinase from invertase and exo-inulinase in order
to hydrolyze inulin and produce oligosaccharides [10,11]. How-
ever, others have focused on the process yields [12] and percentage
of total amount of inulo-oligosaccharides, and gave less attention
to individual IOS. For example, the production of high content
IOS (DP2–7) was carried out by Cho et al. [13] using dual endo-
inulinase system (from Xanthomonas sp. and from Pseudomonas
sp.). Mutanda et al. [6], however, have purified endo-inulinase from
a Novozym 960 preparation and optimized process parameters for
the production of IOS (F3, F4 and F5). In both studies, free enzyme
technology was used that limited the adaptability to industrial
∗
Corresponding author. Tel.: +36 1 482 6041; fax: +36 1 482 6558.
E-mail address: quang.nguyenduc@uni-corvinus.hu (Q.D. Nguyen).
1359-5113/$ – see front matter © 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.procbio.2010.08.028

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Q.D. Nguyen et al. / Process Biochemistry 46 (2011) 298–303
299
scale production because of high cost, stability of operation and
the lack of reusability of the enzyme. In contrast, the advent of
immobilized enzyme technology has led to increase in efforts to
replace conventional enzymatic process with immobilized enzyme
preparations. The advantages of immobilization technology include
(a) allowing the enzymes to process large amounts of substrate
since it can be separated easily from the mixture of substrate
and product(s) thus enabling the enzyme to be reused [14]; (b)
imparting greater stability to the enzyme [15,16], so that it can
be used for the development of continuous process; (c) affording
greater control of the catalytic process; and (d) permitting the eco-
nomical utilization of an otherwise cost-prohibitive [17]. Powerful
and economical effects of immobilized enzyme preparation are
demonstrated by immobilized glucose isomerase in food process-
ing [18] or glucose oxidase/peroxidase in clinical diagnostic [19].
Taking into consideration that chitin is a biopolymer from natu-
ral sources (shellfish) and its promising characteristics including
biocompatibility, hydrophilic feature, biodegradability, and anti-
bacterial properties [20,21], this material has the potential as a low
cost, bifunctional support for enzyme immobilization in both food
and pharmaceutical applications. According to Chang and Juang
[21], more than 10 enzymes could be effectively immobilized by
chitosan. However, the major advantages of this method are indus-
trial applicability and environmental friendly. The immobilization
yield depends largely on the method applied as well as on the
nature of the enzyme. The present study reports the production of
short-chain inulo-oligosaccharides from Jerusalem artichoke juice
using immobilized endo-inulinase from Aspergillus niger.
Fig. 1. Scheme of continuous production system of oligofructose using immobilized
endo-inulinase. Immobilized inulinase was packed onto column reactor with double
sides. Temperature of bioreactor was maintained by thermostat. Substrates (S, inulin
or Jerusalem artichoke juice) were prepared in buffer and fed from bottom of column
using controlled peristaltic pump. Products (P) were collected in other tank. Samples
of both sides (input and output) were taken and analyzed by HPLC.
2.5. Effect of pH and temperature on endo-inulinase activity and stability
The effect of pH on the endo-inulinase activity was studied by monitoring
enzyme activity of both free and immobilized preparations in appropriate buffers at
60 ◦C. Buffer systems used were sodium acetate (pH 3.0–5.5), phosphate (pH 5.5–8.0)
and sodium glycine (pH 8.0–10.0). The optimum temperature of free and immobi-
lized endo-inulinases was determined by measuring the activity between 40 ◦C and
85 ◦C and at optimum pH. Stability of endo-inulinase was investigated by incubating
either 25 mg of support or 25 Unit of free enzyme at different pH (5.0, 5.5 and 6.0)
and at various temperatures (50 ◦C, 55 ◦C, 60 ◦C, 65 ◦C, and 70 ◦C) for a week. Sam-
ples were withdrawn at different time intervals and inulinase activity was assayed
according to the method described above.
2. Materials and methods
2.1. Materials
Endo-inulinase preparation from A. niger was purchased from Megazyme Inter-
national Ireland Ltd. (Co. Wicklow, Ireland). According to the information provided
by the supplier, this enzyme has higher activity on dahlia fructan (65 U/mg) than
on kestose (3.7 U/mg). Therefore, it could be classified as an endo-acting enzyme.
Chitin (Product No. C7170) was obtained from Sigma–Aldrich Inc. (Budapest, Hun-
gary). The inulin with high DP (DPav 25) from dahlia tubers was a Fluka product (F
57614). All other chemicals and reagents were of analytical grade.
2.6. Kinetic studies
Michaelis–Menten constants of free and immobilized enzyme preparations
were determined by monitoring the amount of reducing sugars released from 1%
to 5% (w/v) dahlia inulin (Fluka) Reactions were carried out under optimum condi-
tions (pH 5.5, 60 ◦C for free and pH 6.5, 65 ◦C for immobilized enzyme, respectively).
The values of Km and Vmax were calculated from the initial velocity rates by linear
regression using the Hanes–Woolf method [26].
2.2. Enzyme assay
Free endo-inulinase activity was assayed by incubating 0.5 ml of adequately
diluted enzyme solution with 1 ml of 2% (w/v) inulin from dahlia tubers and 0.5 ml
of 0.1 M sodium acetate buffer (pH 5.5) at 55 ◦C for 30 min [12]. In the case of the
immobilized endo-inulinase, 0.1 g of support was incubated in 10 ml of 1% (w/v)
inulin from dahlia tubers prepared in 0.1 M sodium acetate buffer (pH 5.5) at 55 ◦C
for 30 min. The reducing sugars released were determined by the Somogyi–Nelson
[22,23] method. One enzyme unit is defined as the amount of enzyme that releases
1 ␮mol fructose equivalent per minute under the assay conditions.
2.7. Analysis of oligofructose
Bioconversion was monitored by HPLC (Waters) using the Aminex HPX-42C
0.78 cm × 30 cm column (Bio-Rad, USA) and the Waters 410 RI detector. Distilled
water was used as a mobile phase and data were collected and integrated using
Millennium 4.0 for MS Windows software. The amount of oligofructose was defined
as the sum of the amount of fructo-oligosaccharides in DP range from 3 to 7.
2.3. Determination of protein content
Protein content of samples was determined by the Bradford dye-binding proce-
dure [24] using Bio-Rad Protein Assay Kit (Bio-Rad, USA).
2.8. Bioconversion system
The schematic continuous bioconversion system is presented in Fig. 1.
A
2.4. Immobilization of endo-inulinase
packed-bed column bioreactor (1 cm × 30 cm, 30 ml) containing 10 g (wet weight)
of immobilized endo-inulinase was connected to a peristaltic pump that controlled
the flow rate.
The enzyme was immobilized in three steps [25]. In the first step, chitin was
deacetilised using 0.5N HCl. 10 g of chitin was scaled in a 500 ml glass, then 300 ml
of 0.5N HCl was added and stirred continuously at room temperature for 3 h. The
deacetilised chitin (chitosan) was collected by passing the mixture through a fil-
ter paper and washing in distilled water. The chitosan was then dried overnight at
60 ◦C. In the second step, 10 g of chitosan was scaled into a glass containing 500 ml
of 100 mM sodium acetate buffer (pH 5.5). Subsequently, 10 ml of 25% glutaralde-
hyde was added and mixed gently for 1 h at 4 ◦C. The activated chitosan was filtered
and washed in 100 mM sodium acetate buffer (pH 5.5). In the last step, 5 mg of
endo-inulinase was immobilized onto 1 g carrier (activated chitosan) by initially
suspending 10 g of the carrier in 100 ml of 100 mM sodium acetate buffer (pH 5.5)
followed by the addition of 2 ml of endo-inulinase (50 mg protein). The content
was rotated gently at 4 ◦C overnight using mini-shaker. The immobilized endo-
inulinase preparation was collected by filtration and inulinase activity was checked.
The enzyme activity and protein content were also determined in the filtrate.
In case of dahlia inulin, due to its poor solubility in water, the volumetric pro-
duction of the column was investigated from 2.5% (w/v) up to 11% (w/v) of substrate.
In case of Jerusalem artichoke juice, wide range of substrate concentrations (5% w/v,
10% w/v, 15% w/v, 20% w/v, 25% w/v and 30% w/v based on dry material content)
were prepared. To prevent contamination, 0.02% sodium azide was added to the
substrate. The temperature was maintained using a thermostat. Based on prelim-
inary results the flow rates were kept constant (25 ml/h). Considering the optimal
pH of the immobilized endo-inulinase was in the range of 5.5–6.0, different con-
centrations of substrates (inulin and Jerusalem artichoke juice) were adjusted to pH
5.5 using 50 mM sodium acetate buffer before feeding to the column. The column
was fed from bottom and the bioreactor was operated at 60 ◦C. Bioconversion was
carried out continuously at 60 ◦C for 2 months. Samples were taken in both sides
(substrate and product) after the elution of three times of packed volume.

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0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
1.20
1.00
0.80
0.60
0.40
0.20
0.00
100
80
60
40
20
0
40
50
60
70
80
90
Temperature (OC)
3
4
5
6
7
8
9
10
pH
Immobilized enzyme
Free enzyme
Immobilised enzyme
Free enzyme
Fig. 3. Effect of temperature on the activity of free and immobilized endo-inulinase.
Activities were assayed at pH 5.5 and at different temperatures. Data are means of
three parallel experiments.
Fig. 2. Effect of pH on the activity of free and immobilized endo-inulinase. Activities
were assayed at 55 ◦C and at different pH values using sodium acetate, phosphate
and Tris/HCl buffers. Data are means of three parallel experiments.
lization with covalent linkages, some properties of enzyme such as
optimum pH and temperature do change. Ettalibi and Baratti [29]
reported that after immobilization, optimum pH of inulinase from
Aspergillus ficuum shifted from 4.7 to 5.0. Other immobilized inuli-
nase also showed a shift in pH optima from 5.0 to 5.5 [27,30–32].
The free and immobilized endo-inulinase preparations were
optimally active at 60 ◦C and 65 ◦C, respectively (Fig. 3). The opti-
mum temperature of immobilized enzyme preparation was 5 ◦C
higher compared to free enzyme. Temperature optima of endo-
inulinase from Pseudomonas sp. and A. ficuum (Novozym 230)
increased by 2.5 ◦C and 10 ◦C, respectively, for immobilized prepa-
ration compared to the soluble form [12,29]. Other authors also
reported higher temperature optimum for immobilized inulinase
than free enzyme [33–35]. However, this is not universal to all
enzymes as well as for all immobilization methods. In case of cap-
sules, Fernandes et al. in 2009 [36] reported that free inulinase
displayed the highest activity at 60 ◦C, whereas the immobilized
enzyme showed maximal activity at 55 ◦C. Both free and immobi-
lized endo-inulinase preparations from A. niger lost their activity
rapidly when incubated at temperatures higher than 70 ◦C, most
likely due to its mesophilic origin.
2.9. Statistical analysis
Result values are the mean of triplicate trials or enzyme activity assays. Calcula-
tion of standard deviation, analysis of variances (ANOVA) and other statistical probe
tests were performed using the SPSS software package for MS Windows version 12
(SPSS Inc., USA) and the Statistica v8.0 software package (StatSoft Inc, USA).
3. Results and discussion
After the immobilization process, neither inulinase activity nor
protein content was detected in the supernatant fraction, confirm-
ing that the endo-inulinase covalently bonded to the carrier. The
activity on chitosan (immobilized enzyme fraction) was assayed
and 66% of inulinase activity was recovered. Higher yield (82.60%)
of immobilization was reported by de Paula et al. in 2008 [27] when
immobilized the crude inulinase from Kluyveromyces marxianus
var. bulgaricus onto gelatin. Gill et al. [25] reported 100% yield using
DEAE-Sephacel, QAE-Sephadex and ConA-linked amino-activated
silica beads as carriers. On other carriers (Dowex and Amberlite),
only 63% and 39% enzyme activity was retained [25]. Moreover,
immobilization of fructosyltransferase in Pectinex Ultra SP-L onto
Eupergit C carrier resulted in a maximum of 96% of relative activity
[28]. Thus, the present results are in line with other immobilization
methods.
Both immobilized and free endo-inulinase preparations were
completely stable, when stored at 4 ◦C for 1 year. Also, both prepa-
rations were stable in a pH range between 4.5 and 6.5, and at
temperatures below 55 ◦C (data not shown). More than 98% of the
residual activity was retained after 5 days of incubation under the
relevant conditions (please specify the conditions). After 5 days
of incubation at 60 ◦C and in the same pH range (specify the pH
range), approximately 90% free endo-inulinase and >95% of the
The optimum pH of endo-inulinase was shifted from 4.5–5.0 to
5.5–6.0 after immobilizing onto chitin carrier (Fig. 2). These find-
ing are in agreement with the results (from 5.5 to 6.5) published
by Gill et al. [25] when inulinase from Aspergillus fumigatus was
immobilized onto QAE-Sephadex carrier. Generally, after immobi-
Table 1
Relative activity of free and immobilized endo-inulinase at different time intervals when incubated at pH 5.5 and at different temperatures.
Support Incubation time (h)
0
2
4
8
16
24
48
72
96
120
144
55 ◦
Free enzyme
Immobilized enzyme 100.0 4.4 99.8 4.1 99.4 2.9 99.1 3.2 99.4 2.1 98.6 3.4 98.7 1.9 97.5 4.3 97.5 4.7 97.1 3.8 97.6 3.3
60 ◦C
Free enzyme
Immobilized enzyme 100.0 3.3 99.6 4.1 99.6 1.9 99.5 3.3 98.5 4.2 97.8 2.8 97.1 3.6 96.5 2.1 96.9 2.8 95.2 4.3 95.3 4.8
65 ◦C
Free enzyme
Immobilized enzyme 100.0 3.3 99.5 2.5 98.7 4.2 97.1 3.4 96.5 2.5 95.3 1.9 94.7 4.1 94.1 2.5 93.7 4.3 92.6 4.1 91.4 3.9
70 ◦C
Free enzyme
C
100.0 2.3 99.4 3.8 98.1 2.6 98.1 2.2 97.6 4.2 97.3 3.9 97.5 5.1 97.2 4.2 97.0 3.7 96.4 3.6 96.8 4.5
100.0 3.6 99.5 5.1 98.1 1.7 98.2 3.9 97.2 3.9 96.4 4.3 95.7 2.6 95.0 3.6 93.1 4.1 92.2 4.1 91.5 3.3
100.0 4.3 96.8 4.8 88.5 4.1 79.5 4.6 64.3 2.8 51.8 4.0 46.5 2.6 40.8 1.4 37.9 2.4 35.5 1.9 33.7 1.5
100.0 2.8 52.7 1.2 42.7 1.8 26.7 1.2 22.0 1.1 14.9 0.8 11.9 0.4
7.6 0.8
5.6 0.5
1.5 0.1 0.00 0.1
Immobilized enzyme 100.0 4.2 95.2 3.5 87.9 3.9 81.1 3.7 73.6 2.1 66.9 3.7 61.7 2.9 59.2 1.5 57.9 3.2 51.8 2.8 49.1 4.0
Data are means of three parallel experimental runs.

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301
80
70
60
50
40
30
20
10
0
residual activities were recovered in case of free and immobilized
endo-inulinases, respectively. The half-life (t1/2) of free enzyme
at 65 ◦C and 70 ◦C were estimated to be 1 day and 2 h, respec-
tively (Table 1). For the immobilized endo-inulinase preparation,
approximately 90% and 55% of activities were retained after 5 days
of incubation at 65 ◦C and 70 ◦C, respectively. These results are in
agreement with de Paula et al. [27], who reported the immobiliza-
tion of inulinase from Kluyveromyces marxianus var. bulgaricus onto
a gelatin carrier. Other papers dealing with immobilization of inuli-
nase from A. fumigatus onto a chitin carrier reported that more than
70% of residual activity was obtained after incubation of immo-
bilized inulinase at 64 ◦C for 24 h [25]. Tanriseven and Aslan [28]
reported that free enzyme was fully inactivated at 75 ◦C, whereas
immobilized enzyme retained approximately 30% of its activity.
The immobilized enzyme therefore possessed better heat tolerance
than the free enzyme due to cross-linkages of the enzyme with
glutaraldehyde (covalent linkages between enzyme and carrier),
which protected the conformation of the active site from distortion
or damage by heat [37,38].
0
10
20
30
40
50
60
Operaꢀon ꢀme (days)
Fig. 4. Long-term stability of immobilized inulinase in packed-bed column biore-
actor. Data are mean of three experimental runs at 60 ◦C and at pH 5.5.
Currently, the Hanes–Woolf plotting method has become more
acceptable because it eliminates the effects of lower substrate
concentrations in a kinetic study with Lineweaver–Burk. Km and
Vmax of free endo-inulinase were 2.04% (w/v) and 80.65 U/mg pro-
tein according to Hanes–Woolf plot. For the immobilized enzyme
preparation, the Km and Vmax were 2.19% (w/v) and 291.58 U/g sup-
port. This showed the immobilization procedure did not change
the enzyme affinity toward inulin substrate. Generally, when
entrapped inulinase/invertase in hydrogels for sucrose hydrol-
ysis, these immobilized enzyme preparations exhibited higher
Km than free form due to limitation of diffusion of substrate
inside the matrix [39–41]. In the present study, minimal diffu-
sion limitations were observed. This could be explained by the
immobilization method used. Unlike the entrapment method, in
the present study, the enzyme was covalently linked to chitin
carriers and remained on the surface. Thus, it is much easier to
form the enzyme/substrate complex by decreasing the effects of
substrate diffusion. Also, some authors [42,43] reported that the
covalently linked enzyme preparation was not affected by diffu-
sion limitations. These findings were well reviewed by Kotwal and
Shankar [17]. The Km obtained in the present study is in agreement
with the Km (3.53 mM ≈ 1.94 g/100 ml) of endo-inulinase from A.
niger (Novozym 960) reported by Mutanda et al. [6] and signif-
icantly higher than the Km value (1.3 mM inulin, that is, about
0.75 g/100 ml) for exo-inulinase from A. fumigatus reported by Gill
et al. [25].
the stability of the immobilized enzyme. The optimum temper-
ature of immobilized endo-inulinase was 65 ◦C. It is well known
that reducing the temperature of the operating column leads to
the prevention of loss of enzyme activity in the long-term pro-
cess, although it reduces the bioconversion rate. In theory, the
rate of enzyme activity doubles when the operating temperature
is increased by10 ◦C. Another important factor is the contamina-
tion of the process, which could be overcome by operating at high
temperature. In the food industry, 60 ◦C is generally accepted as
the temperature limit that prevents microbial contamination. The
half-life of the immobilized endo-inulinase in terms of continu-
ous hydrolysis of Jerusalem artichoke juice or dahlia inulin at 60 ◦C
and pH 5.5 was estimated to be 48 days (Fig. 4). Some authors
reported that the half-lives of thermostable exo-inulinase from A.
fumigatus immobilized on chitin, QAE-Sephadex and ConA-linked
amino-activated silica beads under these conditions were 35, 22
and 45 days, respectively [25]. This shows that on the same car-
rier (chitin), immobilized commercial endo-inulinase preparation
exhibited longer (13 days) operation time than the other prepara-
tions.
An increase in substrate concentration (inulin) led to an increase
in relative percentage of DP7, DP6, DP5, DP4 and DP3 (Table 2),
which were 9.0%, 11.2%, 13.3%, 12.2% and 24.3%, respectively. In
case of low concentration of inulin substrate (2.7% w/v), the most
dominant inulo-oligosaccharide in the product was DP3 (33%). In
case of Jerusalem artichoke juice, various concentrations (7.5%
w/v, 10% w/v, 15% w/v, 20% w/v and 25% w/v) of substrate were
loaded onto the bioreactor. According to RI detector response
Temperature and pH play an important role in the long-term
operation of the column, because these factors act directly on
Table 2
Concentration of inulo-oligosaccharides in output fraction of packed-bed column containing immobilized endo-inulinasea.
Substrate
Relative inulo-oligosaccharide content in product (%)
DP7 DP6 DP5
2.6 0.04 3.0 0.6 8.1 0.3
DP4
7.4 0.5
DP3
2.7% (w/v) inulin
5.0% (w/v) inulin
7.6% (w/v) inulin
11% (w/v) inulin
7.5% (w/v) JA juice
33.0 0.6
31.2 0.2
26.0 0.3
24.3 0.2
13.4 0.4
19.3 0.8
13.5 0.5
18.4 0.5
13.7 0.3
17.2 0.8
13.4 0.5
16.5 0.6
13.5 0.8
15.6 0.4
5.1 0.2
7.6 0.2
9.0 0.4
7.3 0.8
10.7 0.5
7.3 0.5
12.4 0.2
7.3 0.4
13.1 0.7
7.3 0.7
13.3 0.8
7.3 0.3
13. 6 0.7
4.0 0.5
10.8 0.8
11.2 0.6
8.9 0.6
10.0 0.5
8.9 0.6
9.6 0.5
8.8 0.5
9.7 0.3
8.9 0.6
10.6 0.2
8.5 0.5
9.9 0.8
11.4 0.8
12.3 0.5
13.3 0.5
9.9 0.2
12.3 0.7
9.7 0.8
11.2 0.4
9.8 0.7
11.5 0.7
9.8 0.2
12.6 0.9
9. 8 0.7
11.8 0.4
9.8 0.5
11.9 0.7
12.2 0.2
12.2 0.8
14.7 0.7
12.3 0.4
14.3 0.7
12.3 0.8
14.1 0.3
12.7 0.3
13.6 0.6
12.7 0.4
14.0 0.7
S
P
S
P
S
P
S
P
S
P
10% (w/v) JA juice
15% (w/v) JA juice
20% (w/v) JA juice
25% (w/v) JA juice
S: substrate (input); P: product (output).
a
Data are means of three different samples.