Enhanced green extraction of phytochemical compound from Eucheuma Cottonii using supercritical CO2 and Sub-critical water as a solvent: Optimization and kinetics modeling

Numerous active ingredients found in Eucheuma cottonii have applications in the food, cosmetic, and pharmaceutical industries, among others. Extraction is one of the biomass separation procedures that yields high purity. This work used supercritical CO2 and subcritical water as a solvent to extract phytochemical components from Eucheuma cottonii. Both solvents used are easily available, environmentally friendly, and affordable. Supercritical CO2 extraction is carried out at a temperature of 60 °C and a pressure of 25 MPa, while Sub-critical water extraction (SWE) is carried out at a temperature of 120 °C − 160 °C and a pressure of 3 MPa − 5 MPa. The yields of β-carotene and linoleic acid were 0.0019 μg/g sample and 0.0841 μg/g sample. Meanwhile, the results of SWE were kappa-carrageenan and total phenolic compounds with the largest yield of 55.8% at a temperature of 160 °C and 5 MPa. The data obtained were then analyzed for optimum operating conditions using Face-centered central composite design (FCCCD), where the optimum operating conditions correspond to the largest value of the TPC yield produced. In addition, the data were analyzed using extraction kinetics modeling, where the results showed agreement with first-order kinetics and the activation energy value was 20.563 KJ/mol.