Seasonal variations in the composition and gel quality of agar from Gracilaria edulis in the Philippines
Issue Date
8-2007
Abstract
Agar from Gracilaria edulis collected in the Philippines is composed primarily of a repeating disaccharide unit of 4-linked 3,6-anhydro-α-L- galactopyranose (LA) and 3-linked 6-O-methyl-β-D-galactopyranose (G6M). Chemical and spectroscopic analyses further revealed partial (19-27 mol %) methylation at O-2 of the LA residues. Sulfate was attached to O-4 of G6M and/or G, with approximately 20% of these residues bearing the substituent. No pyruvate substituent was detected. A seasonal assessment of the composition, rheological and physical properties of Gracilaria edulis agar was undertaken. Constituent sugar analysis revealed a variable degree of methylation (80-91 mol % on O-6 of the G and 19-27 mol % on O-2 of the LA residues); the highest amounts of mono-O-methylated residues (G6M and LA2M) were found in the samples collected in the dry season while the lowest was obtained during the rainy season. The sample collected during the onset of the rainy season contained the lowest amount of sulfate (2.3%) while the cold season sample contained the highest sulfate content (3.2%). Seaweed samples collected during the onset of the rainy season exhibited the highest agar yield, gel strength, deformation, cohesiveness, and melting temperature. Gracilaria edulis agar possesses gel characteristics useful in the food industry. © 2007 by Walter de Gruyter.
Source or Periodical Title
Botanica Marina
ISSN
68055
Volume
50
Issue
3
Page
191-194
Document Type
Article
Language
English
Subject
Agar, FTIR spectroscopy, Gracilaria edulis, Monosaccharide constituent, Seasonality
Recommended Citation
Romero, Jumelita & Montaño, Marco & Merca, Florinia & Villanueva, Ronald & Liao, Ming-Long & Bacic, Antony. (2007). Seasonal variations in the composition and gel quality of agar from Gracilaria edulis in the Philippines. Botanica Marina - BOT MAR. 50. 191-194.
Identifier
https://doi.org/10.1515/BOT.2007.023