Green Extraction and Sustainability Assessment of Total Carotenoids from Carrot (Daucus Carota) Peel Waste using Soybean Oil

The environmental and health impacts of organic solvent extraction for carotenoid recovery highlight the need for a greener, more sustainable process. This study investigates the use of soybean oil as a green, environmentally friendly alternative for recovering carotenoids from carrot (Daucus carota) peels, offering a zero-waste approach to conventional, often toxic organic solvents. A two-factor, three-level full factorial experimental design was employed to evaluate and optimize the temperature (30, 45, and 60 °C) and the liquid-solid (L/S) ratio (20, 30, and 40 mL:g). In addition, Total Carotenoid Content (TCC) was quantified with UV-Visible spectrophotometry. Statistical analyses showed that the L/S ratio primarily drove extraction efficiency (p < 0.01), thereby improving mass transfer and matrix penetration. Temperature (p < 0.01) and its interactions with the L/S ratio (p < 0.01) also significantly enhanced cell wall permeability. The model was reduced, as quadratic terms were insignificant (p > 0.05). The optimal predicted conditions of the reduced model yielded 77.49 ± 13.13µg β-carotene/g of dried peel at a 40 L/S ratio and 30 °C, with validation runs yielding 76.04 ± 3.71 13µg β-carotene/g of dried peel. A final score of 0.59 based on the Path2Green sustainability metrics suggests that the carotenoid extraction process is eco-friendly and low-impact, especially high (+1.00) in biomass utilization, post-treatment, scaling, transport, waste, purification, application, and the use of eco-friendly solvents. These findings demonstrate that soybean oil is an effective and sustainable solvent alternative for carotenoid recovery, offering a practical option for greener industrial processes.