Optimization of Supercritical Fluid Extraction of Essential Oil and Vitamin E from Discarded Tobacco Leaves Using Response Surface Methodology

Abstract

Discarded tobacco leaves, a substantial agricultural by-product, represent an underutilized reservoir of bioactive phytochemicals. This study investigated the application of Supercritical Fluid Extraction (SFE) using CO₂ as a green technology for the recovery of tobacco oleoresin and α-tocopherol (Vitamin E). A Box-Behnken Design (BBD) integrated with Response Surface Methodology (RSM) was employed to optimize critical process variables: extraction pressure, temperature, and time. Statistical analysis identified the model-predicted optimum conditions as 21.3 MPa, 45.8 °C, and 63.4 min, yielding a maximum oleoresin recovery of 1.36%. This empirical result exhibited high concordance with the model prediction, validating the robustness of the optimization. Gas Chromatography-Mass Spectrometry (GC-MS) analysis demonstrated the tunable selectivity of the SFE process. The relative content of the high-value antioxidant Vitamin E was preferentially enriched to 19.1% under density-controlled conditions (25 MPa and 40 °C), minimizing the co-extraction of impurities. These findings established SFE as a superior, eco-friendly strategy for the valorization of tobacco residues, offering a sustainable pathway for the production of functional ingredients for pharmaceutical and cosmetic applications.