Seasonal Variations in the Yield, Gelling Properties, and Chemical Composition of Agars from Gracilaria eucheumoides and Gelidiella acerosa (Rhodophyta) from the Philippines
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R. D. Villanueva
Abstract
The yield, physical, and chemical properties of agars from two Philippine red seaweeds, Gracilaria eucheumoides and Gelidiella acerosa, were investigated on a bimonthly basis. The yield of agar from Gracilaria eucheumoides was at a maximum during the early rainy season (May, 29%) and at a minimum during the summer month of March (20%). In Gelidiella acerosa, a peak in agar yield was also recorded in May (21%), with generally higher yields recorded during the rainy than in the dry season. Agar gel strengths fluctuated from 225 to 430 g cm−2 and from 160 to 820 g cm−2 for Gracilaria eucheumoides and Gelidiella acerosa, respectively, and both agars exhibited strongest gels in July. Significant seasonal variations were observed in the gelling and melting temperatures of agar from Gracilaria eucheumoides, but not from Gelidiella acerosa. Sulphate content only varied slightly in agar samples from Gracilaria eucheumoides, while a higher sulphate content was found in Gelidiella acerosa agar during the dry season. Moreover, the sulphate content in G. acerosa agar fluctuated inversely with the 3,6-anhydrogalactose content. A FT-IR analysis showed a fairly constant spectrum for temporal Gracilaria eucheumoides agar while peaks attributed to S–O vibrations intensified in Gelidiella acerosa samples which were recorded to contain high sulphate residues and possess low gel strengths. Diagnosis of the FT-IR spectra in the 1000–400 cm−1 frequency range was also conducted in comparison with agarose and Gracilaria chilensis agar.
Copyright (c)1999 by Walter de Gruyter GmbH & Co. KG
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Articles in the same Issue
- Comparison of the Phytoplankton Assemblages of the South-Eastern Barents Sea and South-Western Kara Sea: Phytogeographical Status of the Regions
- Intertidal Fungi in Mangalore Harbour, Southern India
- Epiphyte Accrual on Posidonia oceanica (L.) Delile Leaves: Implications for Light Absorption
- The Benthic Marine Algae of Uruguay
- On the Evolution of Interactions between Marine Mesoherbivores and Algae
- Bioaccumulation of Hg, Cd, Pb and Zn in Four Marine Phanerogams and the Alga Caulerpa prolifera (Försskal) Lamouroux from the East Coast of Spain
- Differential Antibacterial Activity of Extracts from Selected Southern African Macroalgal Thalli
- Seasonal Variations in the Yield, Gelling Properties, and Chemical Composition of Agars from Gracilaria eucheumoides and Gelidiella acerosa (Rhodophyta) from the Philippines
- Coexistence of Agaroid and Carrageenan Structures in a Polysaccharide from the Red Seaweed Rhodomela larix (Turner) C. Ag.
- Life History of a Marine Dinoflagellate Pyrophacus steinii (Schiller) Wall et Dale
- Halogenated Secondary Metabolites of Laurencia similis (Rhodomelaceae, Rhodophyta)
