National Committee on Marine Sciences (NCMS)
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- Optimized agar extraction from Gracilaria eucheumoides HarveyVillanueva, R. D.; Pagba, C. V.; Montaño, N. E. (Walter de Gruyter, 1997)A 33 factorial experimental design was utilized to determine the optimum alkali pretreatment conditions in the extraction of agar from Gracilaria eucheumoides. Three levels from each of three factors were considered: Temperature, 70, 80, 90 °C; NaOH concentration, 4, 7, 10% and; treatment duration, 0.5, 1, 2 h. The optimum conditions were found to be 90 °C, 10% and 2 h. The gel strength of the agar yielded under these conditions was 432 ± 43 g/cm2. The effects of the different alkali pretreatment conditions to the agar yield and 3, 6-anhydrogalactose and sulphate contents were also determined. Agar yield was higher at lower temperature, stronger alkali solution and shorter treatment duration. Higher 3, 6-ahydrogalactose content and lower sulphate level were obtained at higher temperature, higher alkali concentration and longer duration of treatment.