Villanueva, R. D.Pagba, C. V.Montaño, N. E.2025-03-261997Villanueva, R. D., Pagba, C. V., & Montaño, N. E. (1997). Optimized agar extraction from <i>Gracilaria eucheumoides</i> Harvey. <i>Botanica Marina, 40</i>(1–6), 369–372. https://doi.org/10.1515/botm.1997.40.1-6.3690006-80551437-432310.1515/botm.1997.40.1-6.369https://repository.unesco.gov.ph/handle/123456789/196A 33 factorial experimental design was utilized to determine the optimum alkali pretreatment conditions in the extraction of agar from <i>Gracilaria eucheumoides</i>. 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.enMarine algaeAgarExtraction (Chemistry)AlkaliesArticleSDG 14 - Life below waterSDG 9 - Industry, innovation and infrastructureseaweedsseaweed processingChallenge 9: Skills, knowledge, and technology for all