THE CONTENT AND THE PHYSICO-CHEMICAL CHARACTERISTICS OF ALGINATB EXTRACTED FROM THREE SPECIES OF BROWN ALGAE

Tlrree species of brown algae (Scrg<lr*t.tn cinen:nm, Hormophyca tril1tt,etra, and, Turhinuriu cortoille.s) harvested from Pari Island of the Seribu Islands, North Jakarta, in November 1992 were used for this study. fire alginate content of those brown algae were 13.41, 17.04, and 15.76%, respectively. Sensory evaluation, proximate analysis, and physico.chemical test were performed on alginate extract prepared from these brown algae and on commercial alginate product. Results showed no sigrrifican0 difference on properties of both products. Moreover, the alginate obtained fronr this study fulfrlled requirements established by Ekstra Farmakope Indonesia (1974) and the United States Pharmacopeia: the National tr'ormulary (f985).


INTRODUCTION
During the period of 1990-1996 Indonesia imported around 2,000 tons alginate per year which is equal to arorrnd US $8.6 millions ( Table  1). Alginate is a polysaccharide compound which can be extracted frorn brown algae (Phaeophyceae) (Bold & Wynne, 1985;Lewin, 1962;Stewart,  Year Quantity Value (1.000 ton) (million US$) Sargassurn spp., Hormophysa spp., and Turbinaria spp., was conducted. The physico-chemical characteristics of the alginate produced were compared with the commercial product and with the product requirements as stated in the Ekstra Farmakope Indonesia (1974). The results gained from this. study could provide useful information for the development of science and technology in Indonesian brown algae business.

Materials
Three species of fresh brown algae, i.e. Sar g assu m c ine r e urn, H or mop hy w tr ique tr a, and Turbinaria conoides were collected from Pari Island waters of Seribu Islands, Jakarta Bay, in November 1992. All chemicals used in this studv were classified as pure analytical grade.

Methods
Alginate was extracted by Le Gloachec-Herter method (Wheaton & Lawson, 1985;Soegiartono, L977). Fresh algae was washed using sea water to remove dirts and then sun dried. Alginate was released from plant tissue using I% CaCl, solution, and extracted with 1.5% Na., CO" solution. Clarification and oxidation *er" ih"o earried out by addition of lO% NaOCI solution, and the alginate was precipitatedby HCI solution at pH 2.3-3.2. Alginate was purified using alcohol before drying in the oven at 105 "C. The flow diagrarn of the process is shown in Figure 1 1974\. The species of brown algae which are generally rrsed as a sorrrce of alginate are Laminorio spp., Macr o c l stis spp., and As cophv lum spp. (Wheaton & Lawson, 1985 Proximate composition of the alginate product was analysed in triplicate by AOAC (1980) methods.
Sensory properties of the alginate including form, colour, odour and taste were evaluated by 10 panelists. The microbial load of the product was analysed according to Miwa & Low method ( 1992). Physico-chemical properties of alginate were determined aceording to the method described by "Ekstra Farmakope Indonesia" (L974) and the United States Pharmacopeia: the National Formulary (1985). Viscosity of alginate solution was determined using a viscometer.

RESULTS AND DISCUSSION
The results of proximate composition analysis of brown atgae (Phaeophyceae) are shown in the Drying 50-60"c w) in the dried raw materials is relatively high and it is hoped that mostly is alginate compound. The content of ash (32-39%, w/w) is high, it means that the raw materials contain a lot of minerals as impurities. The content of protein (5.20-6.20%, w/w) is relatively high but the fat content (0.50-L.15o/o, w/w) is relatively low. To get high grade of alginate product, other substances or impurities contained in the dried raw materials must be eliminated or reduced as low as possible through a sequence of treatments as shown in Figure 1.
The yields of alginate extracted from these three species ofbrown algae are shown in Table 3. The highest yield was obtained from Hormophysa triquetra (L7.04%), followed by Turbinaria conoides (I5.L6%) and Sorgossum cinereum (I3.4Lo/o). Sargassum spp. from other countries had an alginate content in the range of 9-32o/o (Atmadja, 1991). The alginate content of   (south coast of Java) ranged frorn 8.9 to I5.5% (Soegiartono, 1977 Durairatnam & Grero, 1969). The quality of alginate is also influenced by the extraction method and the pH of extracting solvent (Durairatnarn & Grero, 1969). The arnount and the ratio between rnannuronic and guluronic acid in the brown algae depend on algae species, season, and growth condition (Stewart, 1974 which alginate cornpounds can be slowly dissolved from plant tissue is 1.5% NarCO" solution. If the concentration of NarCO" is too high, the alginate polymer will be degraded. McDowell (1977) stated that the addition of acid or base which brings the pH of alginate solution to below 5 or above g will accelerate depolyrnerisation of the alginate. Based on the physical properties of alginate as shown in Table 4, the alginate product resulted from this study meets the reqtrirements as described by "Ekstra Farmakope Indonesia" (L974) and the United States Pharmacopeia: the National Forrnulary (1985). It means that alginate produced in this study could be classified as a good quality product. Nott':*)(l,rttttttlt'r'ittl Sorlitttrt Algirratt'**) llt'fi'rt'nt'o: El<stra l,'arrrrakolx. lrrrlrrresin (11)74) conoides, was 14,4I, 14.75, and 14.67%, respectively (Table 5). The ash contents was 12.83, 19.17 and 22.02%, respectively. The moisture and ash contents were relatively high but the values were stiil in the range as required by "Ekstra Farmakope Indonesia" (1974) and the United States Pharrnacopeia: the National Fonnulary ( 1985). Moisture content of alginate was less than 15% and ash content was in the range o1 1g-!4ttit.
Microbial analysis of the product showed that Salmonella and E. coli were absent. It means that the process practiced in this study was able to keep the product in hygienic condition. Thus, the product can be utilized for food or pharmaceutic al purposes.