Optimizing phytosterols extraction from Codium tomentosum using bio-based molecular solvents and accelerated solvent extraction

In the present work, a new approach comprising the use of accelerated solvent extraction (ASE) with bio-based molecular solvents for extracting phytosterols from the macroalga Codium tomentosum was developed. Preliminarily, four different solvents (ethanol, ethyl acetate, 2-methyltetrahydrofuran and propan-2-ol) at two distinct temperatures (40 and 100 °C) were tested, with ethyl acetate at 40 °C yielding the highest phytosterol content (63.0 ± 0.14 mg phytosterols/g extract). Subsequently, the extraction conditions, namely the temperature (40–100 °C), time of extraction (15–75 min) and biomass weight (0.2–0.7 g) were optimized using a Box-Behnken design and response surface methodology (RSM). The optimal extraction conditions to maximize the phytosterols content were determined to be time of 15 min, temperature of 40 °C and biomass weight of 0.4 g biomass, for which the experimental phytosterol content was achieved to be 70.3 ± 0.20 mg of phytosterols/g of extract. The extract obtained at the optimal ASE conditions was further compared with extracts obtained by two conventional extraction procedures. Finally, the environmental analysis footprint of the ASE process compared to conventional methods was carried out using the EcoScale methodology. Overall, our process resulted in a more enriched-phytosterols extract compared to Soxhlet and solid-liquid extractions, while at the same time significantly reducing the extraction time.