<![CDATA[This study aimed to optimize carrageenan extraction from sea grape (Caulerpa sp.) and to characterize physicochemical properties in comparison with commercial carrageenan using Ultrasonic-Assisted Extraction (UAE) and Microwave-Assisted Extraction (MAE) methods. Extraction optimization was conducted using Response Surface Methodology (RSM), a Box-Benhken Design was employed to evaluate the effects of sample amount, solvent concentration, and time on yield, viscosity, and sulfate content. The extracted carrageenan was then analyzed for yield, moisture content, ash content, sulfate content, viscosity, water holding capacity (WHC), and solubility. The results showed that the optimum extraction conditions for the MAE method were obtained at a sample size of 40 g, a solvent concentration of 10%, and an extraction time of 40 minutes, resulting in a predicted carrageenan yield of 15.23%, 3.66 cP viscosity, and 27.61% sulfate content. Experimental validation under the predicted optimum conditions yielded an extraction yield of 14.53%, viscosity of 3.68 cP, and sulfate content of 24.71%. Meanwhile, the UAE method achieved optimum conditions at a sample size of 20 g, a solvent concentration of 9.11%, and an extraction time of 40 minutes, with a predicted yield of 11.01%, 3.54 cP viscosity, and 18.55% sulfate content. Experimental validation under the predicted optimum conditions yielded an extraction yield of 13.12%, viscosity of 3.60 cP, and sulfate content of 17.30 %. Under these conditions, the extracted carrageenan showed a water content of 9.34–9.94%, ash content of 53.01–54.72%, sulfate content of 17.30–24.21%, viscosity of 3.60–3.68 cP, water holding capacity (WHC) of 102.93–110.61 g/g, and solubility ranging from 71.80% to 95.23% depending on temperature. Compared to commercial carrageenan, the extracted product exhibits a much lower viscosity but a comparable sulfate content that is still within the standard range.]]>
