ACTA OCEANOGRAPHICA T AIWANICA
SCIENCE REPORTS OF THE NATIONAL TAIWAN UNIVERSITY
NO.7, PP. 193-199, 5 TABLES, DECEMBER, 1977
STUDIES ON ALGIN FROM BROWN ALGAE OF TAIWAN1,!
II. Conditions for the extraction of algin from
Sargassum cristae/olium C. Agardh
HONG-NONG CHOU3 and YOUNG-MENG CHIANG3
ABSTRACT
We studied Sargassum cristaefolium for the factors which may affect the yield and viscosity of
sodium alginate in the process of extraction and found that the raw material which was dried in the
sun and stored in sealed, dry bottles gave the highest viscosity of alginate. The material extracted
with 1% solution of Na 2COa gave more and better quality of alginate than with 3% solution of
NaaCOa, which seemed to be too high for the extraction and also not to be as economical. The algae
which were washed with fresh water before being stored for six months showed no significant deterioration in the viscosity of alginate; treatment of the material with 1% formalin for 24 hours
before extraction raises the quality of alginate by increasing its viscosity and reducing its color.
Extraction of algin by heating raises the yield and viscosity but it also increases the pigments of the
product.
INTRODUCTION
As reported in the previous paper (Chou and Chiang, 1976), some species of Sargassum,
such as S. cristaefolium, S. duplicatum, S. siliquosum and S. sandei, which grow abundantly on
the coasts of Taiwan and its offshore islands are suitable for the industrial production of algin.
In order to find the most suitable process for alginate producton from Sargassum collected
from Taiwan, we carried out experiments on the extraction of alginate under various conditions,
and this is the report of these experiments.
MATERIAL AND METHODS
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Plants of Sargassum cristaefolium were collected at Patoutzu, near Keelung on 2 July, 1976.
All plants were about at the same growing stage of between 50 to 75 em long and bearing
receptacles.
Effects of NazCO a concentration and drying methods, storage conditions and length of storage
period of raw material on the yield and viscosity of sodium alginate: About 14 kg of fresh
material, after being washed with fresh water, was divided into two parts by weight for drying. One was dried in the sun (the outdoor temperature was 32"C at noon), the other W:lS
kept in an oven at a temperature of 46" ± 1"C). After drying for two days, the moisture content of the samples was 11.6% and 11.4% respectively.
The dried algae were cut into pieces of about 5 em long and part of them were stored in
a sealed bottle containing silica gel and the other were stored in a PE webbed bag respectively.
A sample of each set was extracted every other month during the following six months storage
1. Contribution No. 114, Institute of Oceanography, National Taiwan University.
2. This study was supported by Chinese-American Joint Commission on Rural Reconstruction
Grant 77-A31-0-933.
3. Institute of Oceanography, National Taiwan University, Taipei Taiwan, Republic of China.
193
194
Hong-Nang Chou and Young-Meng Chiang
period which followed and the extraction was made triplicately with different concentration
of NasCO a (0.5, 1.0 and 3.0%). The principal method of extraction was the same as described
in the preceeding paper (Chou and Chiang, 1976).
Effects of temperature and the treatment of formalin on the yield and viscosity of sodium
alginate: The sample was divided into parts, one was immersed in 1% formalin solution and
the other was placed in distilled water for 24 hours before extraction. Both the formalin and
distilled water soaked samples were extracted at 20°C (room temperature), and at 50°C and
70°C in a water bath. The procedure of the extraction was the same as mentioned above
except that for heating process. The soaking duration in Na 2COa at 50°C and 70°C was for
one hour for each solution instead of overnight.
The results were analysed by anova and t-test (Sokal and Rohlf, 1969).
RESULTS AND DISCUSSION
There was considerable variation in the quantity, quality and the color of algin depending
on the method of extraction, pretreatment of the raw material and the amount of chemicals
applied.
A. Effects of Na 2COa concentration: From Tables 1 and 2, we find that the material
extracted with 1% Na 2COa gave the highest yield (26.8%) of alginate and the alginate extracted
showed the highest viscosity (234 cp). Plants extracted with 3% Na2COa gave the lowest
yield (26%) and viscosity (163 cp) of sodium alginate. There was no significant difference in
the yield and viscosity of the alginate which was extracted with 1% and 0.5% Na2COa, but
the alginic acid gel extracted with 0.5% Na 2COa contained much more water than that extracted with 1% Na 2COa. Therefore it was more difficult to filter and to remove the water from
the gel extracted with 0.5% Na2COS after the acid treatment.
In the study of Sargassum pallidum, Tseng anh Ji (1962) found that a high concentration
of Na 2COS (3 to 5%) could cause the reduction of yield and viscosity of sodium alginate.
Mamapat (1969) also mentioned that higher concentrations of the extractive solution resulted
either in heavy losses in yield or in increased weights. The findings of their studies concurred
with our results. These facts prove that a high concentration of Na 2COa can cause degradation of algin and the reduction of yield. It also requires more acid to precipitate the gel
when a higher concentration of sodium carbonate has been applied. Therefore it is not feasible
to use higher concentrations of sodium carbonate for the extraction of algin.
B. Effects of drying: As shown in Tables 1 and 2, the sun dried material produced sodium
alginate with higher viscosity (241 cp) than that of the oven-dried (164 cp), but the yield of
the former (25.8%) was lower than that of the latter (27.2%).
The reason for the deterioration of the viscosity in the oven dried material was probably
due to the fact that the mass of algae could not dry quickly, and the inner part remained
moist long after the outer part was dry, and therefore the alginic acid in the thallus was degraded by oxidation and perhaps by the microbial activity during the drying period. The
reduction in the yield of the sun dried material was due to the loss of sodium alginate because
of the difficulty of filtrating a material of such high viscosity.
C. Effects of storage condition: The two storage conditions used in this experiment were:
first in a sealed, dry bottle and the other, in a bag webbed with plastic strings. The results
(Tables 1 and 2) obtained show that the material stored in the former condition gave less
yield (25.4%) but higher viscosity (248 cp) of algin than that stored under the latter condition
which gave the results of 27.6% and 157 cp respectively.
Tseng and Ji (1962) found that high temperature and high humidity will cause serious deterioration of algin in Sargassum, Ji and Shi (1962) further pointed out that the water content
of the raw material was not the only major factor in the degradation of algin during the stoTAO
Studies on Algin from Brown Algae of Taiwan
195
Table 1. Concentration of Na2COa> drying method, and storage condition of raw
material in relation to the yield of sodium alginate produced at different
period of storage. The variables were determined by the equation:
wt, of Na. Alg obtained (in dry base)
Yield ('Yo) =-wC-6Falgae extractea(iti-dry-base)*Factor A
Na 2COs concentration
for extraction in %
Factor B
duration of
storage in month
I
(wjw)
Factor C
drying method
________ -l~
~
D1 dried by
sun
sealed bottle
D2 dried by
Sa stored in plastic
oven
webbed bag
I
Factor
C*
B*
Factor
D*
1---
Cs
26.6
25.1
26.3
26.6
25.1
26.3
78.0
j
S2
27.7
30.5
Ii
::
~~:~
~;:~-I-~::r-r-::-~--I-------
I
28.4
27.4
30.5
iI
I
~~::
28.4
86.6
]
I
I
86.6
26.9
~~:~
, I
~~:~
S2
29.7
26.6
i
27.7
I
84.0
,
S1
23.8
I
24.8
24.1
I
72.7
i
S2
28.2
I
30.9
28.9
I
88.0
J
II::
--------~--
I
:~:~
--~ -~----2~~ --~;~.3--i -~1--;5.4-----~-
-- -,--- - - ------------1------ --I --- ---1------1
Ms
D
2
I
1_ D'_J= ::
I
I
Da
I,
II
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~::
26. 7
- ;::~ -1------
24. 9
21.1
71.5
25.1
80.5
--'-------7----'-------;-------1271.6
415.4
428.8
- I - - - - - - r - - --------27.6!
22.8
S2
25.1
30.3
S1
I
I
427.4
SUM
26.7
MEAN
D2
---- --
26.0
26.8
Factor C*
Factor D*
I
-- ~:; -I :::: -!
-,~-
----~
I
------1'-----
27.7
1---- -----
a
78.0
S1
,
I
-~-~-I~D
C2
1------- ---1---------;------,--
Da
I
C1
MEAN
SUM
--------------
-------~-------------r-
I
---+
S1
I
S2
I
Ma
Factor A*
I
I ---
J
26.5
SUM
MEAN
S1
299.2
310.0
609.2
25.4
S2
320.0
342.4
662.4
27.6
SUM
619.2
652.4
1271.6
25.8
27.2
MEAN
_
i S1 stored in
C 10.5
C 2 1.0
c, 3.0
Factor
-
Factor D
storage condition
I
26.5
196
Hong-Nong Chou and Young-Meng Chiang
Table 2. Concentration of Na 2CO a, drying method, and storage condition of raw
material in relation to the viscosity of sodium alginate produced at
different period of storage. The variables were determined with a viscometer (Model BM, Tokyo Keiki Seizosho Co, LTD) at 25'C in 1%
solution and measured in cpo
Factor
B*
Factor
C*
- - - _ .. -
- - - - - - - - - _..
-
Factor A*
Factor
D*
C1
__ ..
--
Sl
S2
D1
M1
_ .. _I
D2
- - '---,-'--
..., ' -
- - - - ---
SUM
-_._--
..
I
Ca
_-
MEAN
____ J
199
199
320
320
185
185
704
704
159
159
97
97
146
146
402
402
_
184
-
s,
S2
T-
--
--,------
265
268
194
237
782
675
281
220
155
74
661
429
212
--
-
--
-
--------I
:
287
185
191
.
136
____
I
Ma
-------------
373
141
-_._--
,
I
425
J
98
81
232
77
390
728
238
362
75
113
56
1203
369
135
141
347
162
402
37
3350
209
3751
234
2615
163
I
I
180
I
---------
-
-----:------------ ---------~._----_._ _
SUM
MEAN
Factor C*
3570
2213
5783
241
2372
1561
3933
164
------,._--'-_ ..-
--_.
__ ...... _--- -_.... -
5942
3774
9716
233
9716
202
SUM
-
Sl
S2
SUM
MEAN
._.-
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D2
Factor D*
* The same as
!
881
465
MEAN
-
- - - - - _ .. _ , - - - - -
248
157
202
in Table 1.
rage period of raw material, but the free oxygen might have also played an important role.
The results of this study also support these explanations.
The raw material stored in the bag could easily absorb the water from the outside and
furthermore, these would be more free oxygen in the bag than in the sealed bottle.
D. Effects of storage period: Generally the yield of the algin decreases gradually as the
storage period increase (Table 1). But the degree of reduction in yield depends on the storage
197
Studies on Algin from Brown Algae of Taiwan
conditions of the raw material. On the other hand, the viscosity of alginate was not affected
significantly by the duration of storage (Table 2). This result differs from that reported in
the preceeding paper (Chou and Chiang, 1976) where we found that the viscosity of alginate
extracted from Endarachne binghamiae deteriorated from 3680 cp to 75 cp after six months storage of the raw material. In the study of Sargassum pallidum, Tseng and Ji (1962) found that
the viscosity of alginate in raw material deteriorated during the storage. The differences in
these reports may be due to the difference in the species of algae used or perhaps due to the
differences in pretreatment of the raw material before storage. In this study we washed the
algae several times with fresh water so that there was little or no remaining salt on the algae
to effect the water content of the material and to cause the degradation of algin.
E. Effect of temperature: The result showed that the material extracted at 20'C gave the
lowest yield (25.9%) and viscosity (62 cp) of alginate (Tables 3 and 4). However the algae
extracted at 50'C and 70·C gave good yields and viscosity (Tables 3 and 4), but no significant
differences could be noticed between them.
Table 3. Temperature and the treatment of formalin in relation to the yield of
sodium alginate produced. The variables were measured with replication and in %.
A
B
Extractive
temperature
_____.__.
~-----_
26.5
28.7
24.6
..
MEAN
SUM
distilled H20 as control
1% formalin treatment
_------
25.0
32.0
32.9
----,
-~--- . ' - - - - - ,
-
22.7
29.4
29.5
!
..
1
" _ _1
29.2
35.3
35.1
_
25.9
31.4
30.5
130.4
125.4
122.1
169.7
28.3
SUM
MEAN
Table 4. Temperature and the treatment of formalin in relation to the viscosity
of sodium alginate produced. The variables were measured with replication and in cp,
B
I
Extractive
temperature I
A
1% formalin treatment
- -
-------
,
- -
'--.-
SUM
722
MEAN
120
distilled H 20 as control
.
-----
86
118
124
117
156
121
,
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.
22
85
46
22
116
124
415
69
c
MEAN
SUM
.
~
247
475
415
.. _..
_
62
119
104
1137
95
Undoubtly the heating process not only can make the extraction of algin easier by the
destruction of algal material, but also can extract some alginates of higher molecular weight
and also other polysaccharides, which were mixed with sodium alginate and helped to raise
the yield and viscosity of the product.
F. Effects of formalin treatment: The treatment of the raw material with formalin prior
to the extraction could not raise the yield but improved the quality of the alginate a lot
(Tables 3 and 4). The mean viscosity of alginate produced from the algae treated with for-
198
Hong-Nang Chou and Young-Meng Chiang
malin was much higher(120 cp) than that of the control (69 cp),
It is known that most brown algae contain various amounts of phenolic compounds
(fucosan) which is responsible for the brown color of their alkali extracts and alginates, and
that formaldehyde can react with the phenolic compounds to make them insoluble in acid and
alkali. Smidsrod, et al (1963 a) explained that the higher viscosity of alginate extracted from
algae treated with formalin was due to the process of oxidative degradation of alginate which
was caused by some reducing compounds present in the phenolic compounds being deterred by
the presence of formaldehyde. They (1963 b) found further that the addition of reducing substances increased the rate of degradation of alginate, and the process was retarded by pretreatment of algae with formaldehyde. The alginate extracted from the algae treated with formalin
was also paler than that of the control (Table 5).
Table 5. Temperature and the treatment of formalin in relation to the color of
sodium alginate produced. The color of sodium alignate in 1% solution
was determined with a Lovibond tintometer type D.
!
Temperature Treatment I
of extraction of formalinI
!
20°C
f,
I
50°C
70°C
{
{I
1%
0%
1%
0%
1%
0%
Replicates
Red
,
Yellow
;
Blue
I
------------------
1.7
8.4
2.0
9.7
3.6
11.2
4.1
39.0
5.0
50.7
11.0
59.0
0.0
0.8
0.2
0.9
0.2
0.8
Red
Yellow
____I ___~-
2.1
5.2
5.6
7.5
3.6
3.8
5.1
34.0
23.0
39.0
16.0
20.2
Blue
--,----._--
0.0
0.4
0.6
0.7
0.2
0.3
ACKNOWLEDGEMENTS
The authors are grateful to Dr. T. Y. Liu, chairman of Chemistry Department, Food
Industry Research and Development Institute for his valuable suggestions and permitting us to
use some of his instruments for this study. The assistance of the Fishery Division of ChineseAmerican Joint Commission on Rural Reconstrnction is also acknowledged.
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REFERENCES CITED
CHOU, H. N. and Y. M. CHIANG (1976) Studies on algin from grown algae of Taiwan. 1. Estimation
of yield and quality of algin. Acta Oceanogr. Taiwanica 6: 135-139.
JI, M. H. and S. Y. SHI (1962) Studies on algin from Sargassum. IV. The pretreatment before extraction of seaweed and the storage conditions for the seaweed and alginate. Studia Marina Sinica
1: 170-179.
MANAPAT, A. L. (1969) Alginic acid from some Philippine brown algae. Acta Manilana Ser, A(3):
36-45.
SMIDSROD, 0., HAUG, and B. LARSEN (1963a) The influence of reducing substances on the rate of
degradation of alginates. Acta Chern. Scand. 17: 1473-1474.
, (1963b) Degradation of alginate in the presence of reducing compounds. Acta Chern.
Scand, 17: 2628-2637.
SOKAL, R. R. and F. J. ROHLF (1969) Biometry, 776 pp: Freeman and Company, San Francisco.
TSENG, C. K. and M. H. JI (1962) Studies on the algin from Sargassum. 1. Conditions for the extraction of algin from Sargassum pallidum. Studia Marina Sinica I: 140-158.
Studies on Algin from Brown Algae of Tliiwan
199
稱瀑膠的研究 II.禍瀑膠之萃取條件
周定農
摘
?主永棉
要
在本實驗裹，我們測試 7一些在萃取過程中可能影響到馬尾藻禍藻膠收量與質地的因于。由馬尾
藻 s. cristaefolium 抽取揭藻膠的結果發現 : Na ZC03 的萃取濃度 以1% 較經濟且抽 出 之產 品 品質較
好;以在陽光下晒乾，密封乾燥財藏的原料藻頭，萃取所得的揭藻酸鍋品質最好;克分洗淨鹽份的原
料，在~'J藏六個月後，其揭藻酸品質不變。叉以 1 %福馬林處理原料 24小時，可增加黏度，減少色
素沉澱而提高產品品質;加溫萃取不但可增加產量，且可提高黏度，唯使產品顏色加深。
TAO