Determination of the nutritional and bioactive properties of selected marine brown algae (phaeophyta) and the potential as a herbal tea

Goh , Pei Nie (2008) Determination of the nutritional and bioactive properties of selected marine brown algae (phaeophyta) and the potential as a herbal tea. Masters thesis, University Malaysia Sabah.

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Abstract

Brown algae could be found growing as an extensive seaweed beds along the coastal areas in Sabah. Present investigation was initiated to better understand their chemical/nutritive contents and their possible utilization in neutraceutical product development. In this study, brown seaweeds Padina boryana, Dictyota dichotoma, Sargassum sp 1, Sargassum siliquosum, and Sargassum polycystum were harvested from Sepanggar Bay, Kota Kinabalu. The investigated biochemical aspects were moisture (78.9 ~ 91.60 %fw), ash (20.66 ~ 52.17 %dw), lipid (0.20 ~ 5.80 %dw), protein (9.15 ~ 25.76 %dw), alginate (4.07-13.95 %dw), and phenolic (0.64 ~ 3.14mg Phloroglucinol/ g dw); values showed variation among the species and/or among the sampling months in certain parameters. Each order in brown seaweed has distinctive features in the fatty acids composition. Detail analyses revealed palmitic acid as the highest type in Sargassum spp with a distinct variation. Other predominant acids present in Sargassum spp were C16:1, C18:1n9c, C22:1n9, C18:3n6, C18:2n6c, and C20:5n3. In Padina boryana, C8:0, C11:0, C20:0, C18:2n6t, C18:1n9c and C22: 1n9 were predominant while C22:2 and C18: 1n9c were predominant in Dictyota dichotoma. Good correlations were observed between the antioxidant activities and total phenolic content of the crude extracts. The strongest free radical-scavenging activity was exhibited by Padina boryana (59.84 ~ 85.53 %), followed by Sargassum spp. (10.3 ~ 52.53 %) and weakest activities being found in Dictyota dichotoma (2.78 ~ 8.37 %). Most of the algal extracts displayed variation activity against assay organisms in this study with 25 ~ 50 % activities against marine environmental bacterial, pathogenic strain and yeast. Dicytota dichotoma possess the greatest antibacterial potential (35 ~ 50 %), followed by Sargassum spp. (35 ~ 45 %) and Padina boryana (25 %). Isolation of the active compound from Sargassum duplicatum (which collected from Tanjung Menggalum, Kudat) was done via bioassay-guided isolation. A mixture of polyunsaturated fatty acids (8.6 %) which were oleic acid (C18: 1n9c) and eicosatrienoic acid (C20:3n6), was isolated and exhibited MIC value of 30μg/disc against Clostridium cellobioparum, Vibrio parahaemolyticus and Escherichia coli. Sargassum duplicatum was then subjected to three drying process, 1) room drying, 2) sun-drying, and 3) roasting, in an effort to develop seaweed tea. Desiccation of seaweeds does affect the total fatty acids where sun-dried seaweed has lower level (480.76 μg/g). The major fatty acids present in these processed seaweeds were similar with the fatty acids mentioned earlier in Sargassum. Roasted seaweed had greater extractability of protein and alginate as well as better antioxidant and antibacterial activities. On the contrary, room-dried seaweed tea infusion have better phenolic content and antioxidant potential but much lower compared to the commercial tea hich are green tea, Pu Er and Sabah tea.

Item Type:Thesis (Masters)
Uncontrolled Keywords:brown algae, seaweed bed, neutraceutical product, herbal tea, Sargassum, bioactive, nutritional
Subjects:Q Science > QK Botany
Divisions:SCHOOL > Borneo Marine Research Institute
ID Code:8948
Deposited By:IR Admin
Deposited On:06 May 2014 13:49
Last Modified:06 May 2014 13:49

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