Supercritical CO2 extraction of lingonberry (Vaccinium vitis-idaea) pomace: Optimization studies using response surface methodology, and extraction kinetics

The lipophilic extracts of lingonberry pomace have important applications in cosmetics, food-grade coatings and films, and other food engineering processes due to their antimicrobial, antioxidant, and hydrophobic properties. In this study, supercritical carbon dioxide extraction (Sc-CO 2 ) was employed to recover valuable lipophilic components from lingonberry pomace. Experiments were designed using the Design of Experiments (DOE) approach. To optimize the extraction conditions, Response Surface Methodology (RSM) was used at experimental ranges with pressure of 190–310 bar, temperature of 38–62 °C, and CO₂ flow rate of 9–21 g/min. Optimization showed that the highest yield of 4.22 wt% was achieved under conditions of 276 bar, 62 °C, and 21 g/min with an extraction time of 380 min. The extraction yield was significantly influenced by the linear effects of CO₂ flow rate and pressure, along with the negative quadratic effect of pressure. Temperature displayed only marginal influence, through its interaction with flow rate. The overall extraction curves (OEC) were developed and well described by spline fitting, and kinetic parameters and the mass transfer coefficients were derived from the experimental data. Both the kinetic parameters and calculated mass transfer coefficients were positively and predominantly influenced by CO 2 flow rate. The observed kinetic behaviour indicated that the extraction process was primarily limited by internal diffusion. These findings on extraction kinetics facilitate the estimation of initial batch cycle durations and provide a basis to define scale‑up criteria essential for process scale-up and subsequent economic evaluations. • Supercritical CO₂ extraction applied to lingonberry pomace. • Extraction parameters optimized using response surface methodology. • The yield of extracts reached 4.22 wt%, under 276 bar, 62 °C and 21 g/min. • Kinetic parameters and mass transfer coefficients were determined.