Alginates are used as stabilizers in food and beverages industry. Previous study on the variable screening of extraction process showed a significant result of alginates extracted from Sargassum sp. This study aimed to optimize the extraction process, utilize and characterize Sodium alginate from locally found Sargassum piluleferum. Response Surface Methodology using Central Composite Design (CCD) of Experiment was employed in order optimize the extraction process. The optimum condition identified for the NaOCl concentration, Na2CO3 concentration and Extractant Ratio (Na2CO3:Samu) were 5.1%, 1.8% and 50:1 respectively. Having a yield of 19.43% in dry basis, 12% moisture, 90.14% purity, pH of 8.4, crude fiber of .16% and 210 mpa s viscosity. FTIR analysis shows similar results with the commercial sodium alginate. In order to test its stabilizing property, the optimum extracted Sodium alginate was added on a sweetpotato beverage and was able to hold and make the solutions stable at 1-1.5% Sodium alginate. Hence, the results of optimized extraction process demonstrated in this study, proves that alginates can be extracted from locally found Sargassum piluleferum.