Characterization of carrageenan extracted from Hypnea bryoides in Oman.
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 × 10(5) 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.
College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman.
Ahmed Ali
AA
Al-Alawi
Insaaf Mohammed
IM
Al-Marhubi
Mohammed Said Moosa
MS
Al-Belushi
Bassam
B
Soussi
D002351:Carrageenan / Q000737:chemistry* / Q000378:metabolism*; D002850:Chromatography, Gel; D009792:Oceans and Seas; D009850:Oman; D012212:Rheology; D000461:Rhodophyta / Q000378:metabolism*
D002351:Carrageenan
Int J Biol Macromol. 2003 Jan 15;31(4-5):177-85
12568926
Eur J Pharm Sci. 2007 Jun;31(2):112-8
17448646
Biomol Eng. 2006 Sep;23(4):201-8
16757212
Colloids Surf B Biointerfaces. 2004 Nov 15;38(3-4):231-40
15542331
Biomol Eng. 2003 Jul;20(4-6):223-8
12919801
Bioresour Technol. 2006 Dec;97(18):2402-6
16311028