Sustainable Carotenoid Extraction from Macroalgae: Optimizing Microwave-Assisted Extraction Using Response Surface Methodology.

This study aimed at optimizing carotenoid extraction using the macroalga Himanthalia elongata (L.) S.F.Gray as a model. Firstly, traditional extraction procedures were employed, using various solvents and temperatures to enhance the extraction conditions. Once the most effective extraction conditions were identified, the study transitioned to a more efficient and environmentally friendly approach, microwave-assisted extraction (MAE). By applying a three-parameter (solid-to-solvent ratio, temperature, and time) Box-Behnken design, the optimal extraction conditions were found to be a solid-to-solvent ratio of 1/13.6 g/mL at 60 °C for 15 min. Under these conditions, the predicted and experimental carotenoid contents were 2.94 and 2.12 µg/mL, respectively. Furthermore, an HPLC-DAD method was developed and validated for the characterization of carotenoids. β-Carotene was the predominant carotenoid in H. elongata, alongside fucoxanthin. The optimized MAE method was applied to other seaweeds, including Fucus vesiculosus L., Codium tomentosum Stackhouse, Gracilaria gracilis (Stackhouse) Steentoft, L.M.Irvine & Farnham, and Eiseinia bicyclis (Kjellman) Setchell. Among all, F. vesiculosus exhibited the highest carotenoid content compared to the others. This study concludes that MAE under optimized conditions is an effective and sustainable approach for carotenoid extraction, providing significant yields of bioactive compounds such as β-carotene and fucoxanthin, which have promising applications in enhancing human health and nutrition.