A Novel Technique For The Decolorization of Sugarcane Juice PDF
A Novel Technique For The Decolorization of Sugarcane Juice PDF
A Novel Technique For The Decolorization of Sugarcane Juice PDF
ABSTRACT: A novel technique for the decolorization of sugarcane juice has been developed. In this method, the
coloration caused by polyphenols during the refining of cane sugar was removed by treatment with octadecylsilylsilicagel. The efficiency of color removal was nearly 90%.
Keywords: sugarcane juice, polyphenols, octadecylsilyl-silicagel, decolorization
Introduction
ODS treatment
To remove insoluble impurities, the following treatments
were conducted: the frozen sugarcane juice was defrosted,
and centrifuged at 17000 x g for 15 min. The supernatant was
the centrifuged juice (CJ).
Ultrafiltration is effective for clarifying sugarcane juice
(Kishihara and others 1989; Kishihara and others 1993). CJ
was subjected to ultrafiltration and the ultrafiltered juice (UJ)
was then subjected to ODS treatment.
An ODS cartridge was conditioned with pure water before
use. The UJ (1000 ml) was loaded onto the ODS cartridge at a
flow rate of 8.3 ml/min. The eluate was designated Sugar
Fraction (SF). The cartridge was washed with 120 ml of pure
water. These washings (SWF) were combined with SF and the
mixture was concentrated to 57.5 brix in vacuo to obtain
syrup. The syrup was next subjected to a crystallization test.
The residue on the cartridge was eluted with 170 ml of 20%
or 50% ethanol, and the eluates (PF1 and PF2, respectively)
were concentrated to dryness. The cartridge was regenerated with 120 ml of pure water. A schematic diagram of the
process is presented in Figure 1. The operation was carried
out 50 times.
Crystallization of sucrose
The syrup was subjected to a crystallization test by using
an automatic laboratory boiling pan, as reported previously
by Kishihara and others 1994. The first obtained crystals
were called A-sugar. The mother liquid was called A-molasses. The crystallization was carried out 3 times and B-sugar,
C-sugar, B molasses, and C molasses were obtained, respectively (Table 1)
Analytical methods
Polyphenol was determined using Folin-Ciocalteu re 2002 Institute of Food Technologists
A-molasses
B-molasses
C-molasses
726
1510
3053
Ca
Mg
1.6
1.3
0.19
0.17
0.11
0.10
of A-sugar, granulated sugar, and raw sugar are shown in Figure 4. A-sugar had a good shape and little color.
The mineral content of the juice before and after ODS
treatment is shown in Table 2. Most of the minerals were
found to remain after this treatment.
As mentioned above, ODS treatment did not remove minerals. It was therefore assessed that these minerals do not inhibit the crystallization of sugar. The color value of the sugars is shown in Table 2. The color value of A-sugar was below
50 IU (equivalent to most of the refined sugar available on
the market). To obtain refined sugar, 2 types of factories are
required, namely, a raw sugar factory and a sugar refinery. It
is possible for the refinery process to be omitted and obtain
white sugar.
Even for C-molasses, the color value was smaller than for
raw sugar. C-molasses from a sugar factory or refinery are
used in various kinds of fermentation as raw materials. However, the highly colored fermentation wastes can cause problems. The results of this study indicated that the ODS method, as described in this paper, can be used to eliminate this
waste problem.
After the juice was treated with ODS, the adsorbed
polyphenols were sequentially desorbed with 20 and 50%
ethanol solutions (Figure 1). The total concentration of the
polyphenols in each fraction was determined as mentioned
above and the results are shown in Table 3. The recoveries of
PF1 and PF2 were 28 and 7%, respectively. The main component of PF1 contains phenylpropanoids and their glucosides;
the main component of PF2 contains flavonoids and their Cglycosides (Yoshida and others 2000). These compounds exhibit strong antioxidant activity (Yoshida and others 2000).
The recovered polyphenols could be useful as antioxidants in
foods. Although more than 50% of the polyphenols moved to
the sugar fractions (SF and SWF), the remainder seemed to
have no negative effect on the color quality.
ODS treatment discharges little waste because ethanol is
1002
1010
122
170
167
Total
polyphenol
(mg)
*Polyphenol
recovery (%)
341
172
23
97
23
100
50
7
28
7
0.034
0.017
0.019
0.057
0.014
used for regenerating ODS. Thus it is possible to recover ethanol from PF1, PF2, and ethanol waste as described in Figure 1.
Conclusions
fective for clarification of sugarcane juice. A-sugar obtained from the juice had a pale color with 48 IU of color value. It may be possible to omit the refining step in the production of sugar. Even the color value of C-molasses
produced by this method was smaller than that of conventional raw sugar. Therefore, C-molasses could be used as a
raw material for fermentation without colored waste. The
polyphenols recovered from the ODS could conceivably be
used as an antioxidant in food. However, there are many
technical improvements needed before commercial practice.
Methods proposed in this study may realize a non-generated
waste, or green process, in the production of sugar.
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MS 20001596 Submitted 12/15/00, Revised 5/2/01, Accepted 5/24/01, Received
5/31/01
We express our deepest thanks to Chigasaki Laboratory, Mitsui Sugar Co. Ltd., for providing
MSX-1 Sugarcane Extract and to Dr. Y. D. Hang and Dr. G. S. Stoewsand for their helpful
advice and encouragement.
Author Okuno is with the Graduate School Science and Technology, and
author Tamaki is with the Faculty of Agriculture at Kobe University, 1
Rokkodaicho, Nada-ku, Kobe 657-8501, Japan. Direct inquiries to author
Tamaki (E-mail: tamaki@kobe-u.ac.jp).