Characterization of Carrageenan Extracted from Hypnea bryoides in Oman
- 522 Downloads
Carrageenophyte red seaweed from Oman, Hypnea bryoides, extracted using three different processes: an aqueous, a mild alkaline, and a more vigorous alkaline extraction was investigated. The resulting extract precipitated by alcohol was subject to chemical and rheological measurements. The total carbohydrate [ranged from 36.78 to 41.65 g/100 g], and ash [39.04 to 43.11 g/100 g] were the most abundant components in H. bryoides and contrary to the two, lipid content was found at a minimum [ranging from 2.95 to 3.38 g/100 g]. Alkali treatment with NaOH allowed complete conversion of kappa (κ) carrageenan form as detected by FTIR analysis. Total yield by alkali treatments gave higher yields (33%) compared with aqueous treatments (12%). However, subsequent aqueous treatment produced mixed carrageenan (μ and κ) with higher molecular weight compared with the alkali treatments which produced single carrageenan form (κ) with molecular weight of 4.1 × 105 Da. The effects of thermal history on gel–sol and sol–gel transition were investigated by differential scanning calorimeter (DSC) and rheology on a pure sample and 1.5% κ-carrageenan mixture added with 30 mM KCl. Transition temperatures from DSC and rheology showed comparable results and were in good agreement with those previously reported.
KeywordsHypnea bryoides Algae Seaweed Phycocolloids FTIR
This work was supported by HM Sultan Qaboos Trust Fund (SR/AGR/FOOD/05/01, PI: B Soussi), University of Gothenburg and the Swedish Research Council (K2005-73-00536, PI: B. Soussi). The authors thank Barry P. Jupp for the valuable discussions; Rabea Al Maqbaly, and Suleiman Al Sheili for their technical assistance.
- Association of Official Analytical Chemists (2000) Official methods of analysis, 17th edn. Association of Official Analytical Chemists, MarylandGoogle Scholar
- Jupp B (2000) Potential economic seaweed in Oman: in the ministry of regional municipalities. Environment and Water Resources, Sultanate of OmanGoogle Scholar
- Jupp B (2002) Guidebook to the seaweeds of the sultanate of Oman, 1st edn. Mazoon Printing, Sultanate of OmanGoogle Scholar
- Mabeau S (1989) Lafiliere algue francaise en 1988: atouts et point de blovage. Oceanis 15:673–692Google Scholar
- McHugh D (2003) A guide to the seaweed industry. FAO Fisheries Technical Paper, No. 441. FAO, Rome, p 105Google Scholar
- Philip K, Campbell R (2006) Hydrocolloids from seaweed resources. CYBERCOLLOIDS, Strandhaven, Currabinny, Carrigaline, County Cork, Ireland. www.cybercolloids.net
- Scientific Committee on Food (2003) Opinion of the Scientific Committee on Food on Carrageenan, Opinion Expressed on 5 March 2003. European Commission Health and Consumer Protection Directorate-General, Brussels, BelgiumGoogle Scholar
- Tuvikene R, Truus K, Vaher M, Kailas T, Martin G, Kersen P (2006) Extraction and quantification of hybrid carrageenans from the biomass of the red algae Furcellaria lumbricalis and Coccotylus truncatus. Proc Estonian Acad Sci Chem 55(1):40–53Google Scholar