Abstract
Four species of brown seaweeds, namely Sargassum baccularia, Sargassum binderi, Sargassum siliquosum and Turbinaria conoides, harvested from Port Dickson, Negeri Sembilan, Malaysia were analysed for ash content, alginate yield and alginate properties.
Seaweeds calcined at 450°C were found to have low amount of non-combustible residue as these were not contaminated by calcareous
animals. Alginate was extracted from these seaweeds by two methods: hot and cold. In the hot method, the storing time was
3 h and the processing temperature was 50°C, whilst in the cold method, the sample was stored overnight at room temperature.
Higher yield of alginate was obtained by the hot method compared to the cold method, but alginate extracted by the cold method
gave higher molecular weight. In the hot method, 49.9% of alginate was extracted from S. siliquosum, followed by T. conoides (41.4%), S. binderi (38.9%) and S. baccularia (26.7%). Alginate extracted from T. conoides has an average molecular weight, M
w, of 8.06 × 105 g mol−1, whereas alginate from S. siliquosum was the lowest in M
w (4.81 × 105 g mol−1) when the extraction was done at room temperature. Alginate extracted from S. baccularia was found to be very heat-sensitive. Its M
w has dropped more than 83%, from 7.52 × 105 to 1.23 × 105 g mol−1, when the extraction temperature was raised. The effect of heat on the extent of depolymerisation of the alginate molecule
of the other three brown seaweed species was less significant, with decrease in molecular weight ranging between 13% and 16%.
Seaweeds calcined at 450°C were found to have low amount of non-combustible residue as these were not contaminated by calcareous
animals. Alginate was extracted from these seaweeds by two methods: hot and cold. In the hot method, the storing time was
3 h and the processing temperature was 50°C, whilst in the cold method, the sample was stored overnight at room temperature.
Higher yield of alginate was obtained by the hot method compared to the cold method, but alginate extracted by the cold method
gave higher molecular weight. In the hot method, 49.9% of alginate was extracted from S. siliquosum, followed by T. conoides (41.4%), S. binderi (38.9%) and S. baccularia (26.7%). Alginate extracted from T. conoides has an average molecular weight, M
w, of 8.06 × 105 g mol−1, whereas alginate from S. siliquosum was the lowest in M
w (4.81 × 105 g mol−1) when the extraction was done at room temperature. Alginate extracted from S. baccularia was found to be very heat-sensitive. Its M
w has dropped more than 83%, from 7.52 × 105 to 1.23 × 105 g mol−1, when the extraction temperature was raised. The effect of heat on the extent of depolymerisation of the alginate molecule
of the other three brown seaweed species was less significant, with decrease in molecular weight ranging between 13% and 16%.
- Content Type Journal Article
- DOI 10.1007/s10811-010-9533-7
- Authors
- Swee-Yong Chee, Jalan Universiti Faculty of Science, Universiti Tunku Abdul Rahman Bandar Barat 31900 Kampar Perak Malaysia
- Ping-Keong Wong, Jalan Universiti Faculty of Science, Universiti Tunku Abdul Rahman Bandar Barat 31900 Kampar Perak Malaysia
- Ching-Lee Wong, Universiti Tunku Abdul Rahman Department of Science, Faculty of Engineering and Science Jalan Genting Kelang 53300 Kuala Lumpur Malaysia
- Journal Journal of Applied Phycology
- Online ISSN 1573-5176
- Print ISSN 0921-8971
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