| Autor: |
Andrés Lemus, Kimon T. Bird, D. Fritz Kapraun, Frank E. Koehn |
| Rok vydání: |
1991 |
| Předmět: |
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| Zdroj: |
Food Hydrocolloids. 5:469-479 |
| ISSN: |
0268-005X |
| DOI: |
10.1016/s0268-005x(09)80105-7 |
| Popis: |
Venezuela and the nearby islands have natural resources of three agarophyte species in the Gelidiales: Gelidium serrulatum, Gelidium floridanum and Pterocladia capillacea. Standing crop biomass for two of these species, G.serrulatum and P.capillacea, varies between 1.4–0.5 and kg dry wt/m2. The agar yield from G.serrulatum and G.floridanum ranges from 12 to 34%, depending on the method of extraction. Agar extraction of both species directly into 0.25 N NaOH provided significantly higher gel strengths (>1100 g/cm2) than either extraction in water or using an alkali pretreatment process of 1.0 N NaOH. Direct extraction of agar in 0.25 N NaOH led to an improvement of gel strength by almost three times that of extraction in water for G.serrulatum. Agar extractions from P. capillacea showed yields ranging from 12 to 32% (depending on extraction process) and gel strengths were highest in the samples extracted after pretreatment in 1.0 N NaOH. In all cases treatment with alkali led to a reduction in percent sulfate of agar and an increase in 3, 6-anhydrogalactose. Both chemical analyses and 13C NMR indicate that the agars from G.serrulatum and G.floridanum are pyruvated. This pyruvated agar did not partition out into different hydrophilic and hydrophobic fractions based on sequential ethanol extraction of G.serrulatum. The agar quality, yields and biomass data suggest that Venezuela could provide commercial quantities of these important agarophytes. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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